RESEARCH CENTRE

Inria Saclay Centre
at Institut Polytechnique de
Paris

IN PARTNERSHIP WITH:

Institut Polytechnique de Paris

2023
ACTIVITY
REPORT

Project-Team
QURIOSITY

Quantum Information Processing and
Communication

IN COLLABORATION WITH: Laboratoire Traitement et
Communication de l’Information

DOMAIN

Algorithmics, Programming, Software
and Architecture

THEME

Algorithmics, Computer Algebra and
Cryptology

Contents

Project-Team QURIOSITY

1 Team members, visitors, external collaborators

2 Overall objectives

3 Research program

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3.1 Research axis 1: Quantum cryptography complexity and hardware frontiers . . . .
3.1.1 Everlasting security from a quantum-computational hybrid model
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3.1.2 Device-independent cryptography . . . . . . . . . . . . . . . . . . . . . . . .
3.1.3 Quantum-enhanced leakage-resilience
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3.1.4 Real-world quantum cryptography . . . . . . . . . . . . . . . . . . . . . . .
3.2 Research axis 2: Multimode photonic systems for quantum information processing
and communications .
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3.2.1 Quantum coherent communications and digital signal processing . . . . . .
3.2.2 Quantum information processing with a programmable frequency processor
3.2.3 Quantum information processing using multimode programmable linear
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3.3 Research axis 3: Mathematical foundations of quantum information . . . . . . . . .
3.3.1 Convex relaxations of quantum optimization problems . . . . . . . . . . . .
Fundamental properties of entropies . . . . . . . . . . . . . . . . . . . . . . .
3.3.2
3.3.3 Complexity and entanglement properties of quantum Gibbs states . . . . .
3.3.4 Mathematical analysis of quantum memories . . . . . . . . . . . . . . . . . .
3.3.5 Tomography of complex quantum systems . . . . . . . . . . . . . . . . . . .
Formal tools for higher-order quantum computation . . . . . . . . . . . . .
3.3.6
3.3.7 Causal structure in quantum theory . . . . . . . . . . . . . . . . . . . . . . .

circuits .

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4 Application domains

5 Social and environmental responsibility

5.1 Footprint of research activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Impact of research results

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6 Highlights of the year

6.1 Five papers selected at QIP 2024 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 Awards and Grants .
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6.3 Quantum Hardware Security Workshop . . . . . . . . . . . . . . . . . . . . . . . . .

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7 New results

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7.1 Research axis 1: Quantum cryptography complexity and hardware frontiers . . . .
7.1.1 Prove the security of hybrid quantum-computational cryptographic proto-
cols by a reduction to a quantum to classical communication complexity
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7.1.2 New self-testing constructions for device-independent cryptography . . . .
7.1.3 Tight finite-size security proof for quantum key distribution protocols . . .
7.2 Research axis 2: Multimode photonic systems for quantum information processing
and communications .
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7.2.1 Quantum Coherent Communication and Digital Signal Processing . . . . .
7.2.2 Parallelizable Synthesis of Arbitrary Single-Qubit Gates with Linear Optics
and Time-Frequency Encoding . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.3 Limitations of GKP-LDPC concatenated codes . . . . . . . . . . . . . . . . .
7.3 Research axis 3: Mathematical foundations of quantum information . . . . . . . . .
7.3.1 Higher-Order quantum computation . . . . . . . . . . . . . . . . . . . . . .
7.3.2 Causal models in quantum theory . . . . . . . . . . . . . . . . . . . . . . . .

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7.3.3 Learning complex quantum states . . . . . . . . . . . . . . . . . . . . . . . .
7.3.4 Complexity of quantum Gibbs states . . . . . . . . . . . . . . . . . . . . . . .
Improved quantum algorithm design from polynomial optimization . . . .
7.3.5

8 Bilateral contracts and grants with industry

8.1 Bilateral contracts with industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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8.2 Grants with industry .

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9 Partnerships and cooperations
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9.1 European initiatives .
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9.1.1 Horizon Europe .
9.1.2 Digital Europe .
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9.1.3 Other european programs/initiatives . . . . . . . . . . . . . . . . . . . . . .
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9.3 Regional initiatives .

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10 Dissemination

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10.1 Promoting scientific activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1.1 Scientific events: organisation . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1.2 Scientific events: selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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10.1.3 Journal .
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10.1.4 Invited talks .
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10.1.5 Leadership within the scientific community . . . . . . . . . . . . . . . . . .
10.1.6 Scientific expertise .
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10.1.7 Research administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.2 Teaching - Supervision - Juries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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10.3.1 Articles and contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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10.3.2 Interventions .

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11 Scientific production

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11.1 Major publications
11.2 Publications of the year .
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Project QURIOSITY

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Project-Team QURIOSITY

Creation of the Project-Team: 2023 January 01

Keywords

Computer sciences and digital sciences

A3.4. – Machine learning and statistics

A4.2. – Correcting codes

A4.3. – Cryptography

A4.3.4. – Quantum Cryptography

A4.6. – Authentication

A5.9. – Signal processing

A6.1.2. – Stochastic Modeling

A6.5. – Mathematical modeling for physical sciences

A7.1. – Algorithms

A7.1.4. – Quantum algorithms

Other research topics and application domains

B5.11. – Quantum systems

B6.2. – Network technologies

B9.1. – Education

B9.10. – Privacy

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Inria Annual Report 2023

1 Team members, visitors, external collaborators

Research Scientist

• Cambyse Rouze [INRIA, ISFP, from Sep 2023]

Faculty Members

• Romain Alléaume [Team leader, Télécom Paris - IP Paris, Professor, HDR]

• Peter Brown [Télécom Paris, Associate Professor]

• Augustin Vanrietvelde [Télécom Paris, Associate Professor]

Post-Doctoral Fellow

• Thomas Van Himbeeck [Telecom Paris]

PhD Students

• Jan Kochanowski [IP Paris, from Nov 2023]

• Francesco Mazzoncini [Telecom Paris]

• Tristan Nemoz [Telecom Paris]

• Thomas Pousset [Télécom Paris]

• Guillaume Ricard [Telecom Paris]

• Pierre Enguerrand Verdier [Orange, CIFRE]

Interns and Apprentices

• Ali Almasi [IP Paris, from Sep 2023, PhD Track student]

• Evdokia Gneusheva [École Polytechnique, Intern, until Mar 2023]

Administrative Assistant

• Natalia Alves [Inria]

External Collaborators

• Pablo Arrighi [Université Paris-Saclay, Team Leader, Inria Team QuACS, HDR]

• Roger Colbeck [University of York, Professor, University of York, HDR]

• Nicolas Fabre [Telecom Paris]

• Omar Fawzi [Inria, Team Leader of QInfo at ENS Lyon, HDR]

• Sylvain Gigan [Ecole Normale Supérieure, HDR]

• Yves Jaouën [Telecom Paris, HDR]

• Robert König [Technical University Münich, Professor, HDR]

• David Peres Garcia [ Universidad Complutense de Madrid , Professor, HDR]

• Cambyse Rouze [Technical University Münich, from Apr 2023 until Aug 2023]

Project QURIOSITY

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• Daniel Stilck França [Inria, Inria Research Scientist at QInfo, ENS Lyon]

• Simone Warzel [Technical University Münich, Professor, HDR]

• Mirjam Weilenmann [University of Geneva]

2 Overall objectives

QURIOSITY’s ambition is to extend the application horizon of quantum information science by
addressing novel questions positioned at the intersection between theoretical research in quantum
information and the engineering of quantum devices, with a focus on approaches combining
digital and quantum photonics technologies.
The overarching goal of the project-team will be to push forward our ability to harness and exploit
high-dimensional complex quantum systems for quantum information processing and quantum
communications purposes.

Leveraging a dual approach combining fundamental research in quantum information with
quantum photonics expertise, QURIOSITY will strive to take advantage of and develop strong
synergies with the unique quantum ecosystem of Saclay and to pursue objectives that have the po-
tential to bring radical advances to several application domains of quantum technologies, ranging
from cryptography to computing:

• Design quantum-enhanced cryptographic hardware, leveraging concepts based on computa-

tional hardness and quantum information.

• Conceive and engineer photonic-based processors and systems capable of achieving quantum

advantage in computation or communication tasks.

• Develop efficient quantum information processing schemes implementable on near-term
hardware and advance the theoretical framework to understand the fundamental limits of
noisy quantum information processing.

3 Research program

The research program that we aim to lead in the QURIOSITY project-team intends to embrace
a relatively wide area of theoretical questions, ranging from quantum cryptography, that we
ambition to combine with complexity-based schemes and establish as a framework to enhance
hardware security, to the mathematical foundations of quantum information and quantum com-
puting. Conversely, we also intend to develop research capable of leveraging photonics and digital
information processing technologies to design systems capable of producing high-dimensional and
controllable quantum states of light in order to push forward the frontiers of quantum information
processing advantage.

3.1 Research axis 1: Quantum cryptography complexity and hardware frontiers

This axis aims to identify and solve frontier research topics in quantum cryptography, from
two main perspectives. First by exploring the interplay between security models - including
computational ones - and theoretical quantum cryptography, allowing to build protocols with
stronger security properties and lesser resource requirements. Second by laying a special emphasis
on interplay between quantum cryptography and hardware security, with the need to develop
extended techniques for quantum cryptographic hardware security certification, but also the idea
to strengthen hardware security and its resilience to information leakage by resorting to quantum
cryptographic constructions.

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Inria Annual Report 2023

3.1.1 Everlasting security from a quantum-computational hybrid model

We proposed in 2015 a security model that we later coined a Quantum Computational Timelock
(QCT) security model. It consists in assuming that computationally secure encryption may only
be broken after time much longer than the coherence time of quantum memories available at
the time of protocol execution. The QCT security model opens the possibility to propose new
quantum cryptographic constructions and in particular to make use of encoding and security proof
techniques that strongly depart from “traditional” quantum conjugate coding that is a central
ingredient in most quantum cryptographic protocols.

Figure 1: QCT security model: Assumption (a): Short-term secure encryption during time tcomp,
during which Alice and Bob can exchange an ephemeral classical secret S. Assumption (b): Time-
limited quantum memory, with coherence time tcoh ≪ tcomp.

The QCT security model opens towards a rich variety of fascinating questions, that we have
certainly not all identified. In the coming years we intend to push forward the theoretical analysis
of several of these questions, that relate to the computational frontiers of quantum cryptography.
One ongoing direction consists in studying key agreement constructions whose security can be
reduced to distributed computational problems that exhibit an exponential separation in terms of
quantum or classical communication complexity.

As an alternative way to build secure protocols in the QCT model, we also intend to investigate
pseudo-random quantum states, which can be seen as a computational variant of a t-design, i.e.
an ensemble of quantum states characterized by the fact that t copies of one sampled state are
statistically indistinguishable from t copies of a states picked uniformly at random. Interestingly,
construction of pseudo-random states can be based on quantum-secure one-way functions, and
therefore from the first assumption. This line of work will also allow us to consider realistic
and pratical constructions of quantum cryptographic schemes based on computational and /or
quantum-hardware security assumptions. We also intend to study constructions for quantum
physically uncloneable functions qPUFs and their aplication.

3.1.2 Device-independent cryptography

Device-independent cryptography allows one to perform quantum cryptography with reduced
or even no trust assumptions on the quantum hardware. It remains a challenge experimentally
and pushing the performance (in terms of key rate, or trust reduction) of device-independent
cryptography defines an active research frontier for quatum cryptography. Recent implementations
of DI-QKD1 [47, 56, 56] have shown that whilst it is now feasible, it has a relatively low rate and
can only be executed over a short distance. By improving the theoretical methods for analyzing
various protocols and security proofs and by improving the protocol design we can look to boost
the rates of these protocols and push them towards a more viable technology. Examples of such
improvements include protocol design modifications [51, 40] and improved methods to calculate
rates [28, 29], [50]. Our goals are to develop better designed protocols and security proofs (assessing

1DI-QKD stand for Device-Independent Quantum Key Distribution

Project QURIOSITY

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their performance in experiments) and to investigate the fundamental limitations of DI protocol
rates Overall pushing the practicality of DI forwards and improving our understanding of its
limitations.

As a complementary line of research we will also investigate prospects of semi-device-independent

protocols as a viable near-term alternative to device-independent security. Proposed protocols
rely on assumptions of system energy [49], dimension bounds and bounded distrust [52] amongst
others. We will investigate alternative assumptions and derive resulting protocols to be analyzed
and subsequently implemented. We will also apply the semi-device-independent framework to
the problem of hardware verification, designing tests to establish that the hardware is functioning
correctly whilst placing limited trust on the components.

3.1.3 Quantum-enhanced leakage-resilience

We will also investigate some questions placed at the intersection between classical hardware
security and quantum cryptography, namely how to prove the security of a cryptographic protocols
when implemented using hardware, such as processors or storage, that may leak some of the
security-sensitive information.

We intend to tackle leakage-resilience cryptography from a new viewpoint, that will consist in
integrating quantum cryptographic constructions as a base layer within cryptographic systems, in
order to obtain security guarantees even in presence of information leakage with strictly weaker
assumptions than existing classical leakage-resilience protocols. We will first consider simple
cryptographic protocols such as One-Time-Pad encryption or authentication protocols relying on
Physically Uncloneable Functions PUFs. We intend for example to investigate how the use of
hybrid classical-quantum cryptographic hardware, comprising quantum channels to interconnect
processors or secure storage sites, can lead to cryptographic protocols with provable security under
some realistic information leakage models.

3.1.4 Real-world quantum cryptography

40 year of quantum cryptography (QC) have lead to major theoretical and technological advances,
with fundamental impact on the field of information security. Market adoption however remains
limited, with major challenges that practical QC still needs to be overcome in order to become
widely used in real-world applications. We identify in particular two main challenges: 1) cryp-
tographic advantage, namely the design of protocols for which the use of QC in combination
with classical cryptography gives a competitive edge over classical cryptography only; 2) security
certification of quantum cryptographic implementations. QURIOSITY intends to actively contribute
to lift these barriers and to foster the development of real-world quantum cryptography and in
particular to the uptake of a French and European industry. The development of a QC industry is
indeed becoming an important topic, with strategic investments from leading scientific countries
(China, Korea, Japan, UK, etc. ) including also notably the EU27 supporthing the EuroQCI initiat-
ive. On the other hand, the adoption of quantum cryptography for real-world application remains
often considered with skepticism by representatives of the cybersecurity community, stressing the
dire need of cross-disciplinary vision combining best-in-class classical and quantum cryptography
expertise.

Regarding cryptographic advantage, our conviction is that one should not aim at construc-
tions where quantum cryptography would just functionally replace classical cryptography, but
on the other hand to identify applications where the use of QC combined with post-quantum
cryptography (PQC) can present strict security gain over PQC alone.

Regarding security certification, it has become a central challenge in particular in the context
of the EuroQCI initiative aiming at developing a pan-European quantum communication infra-
structure, together with an industry, in the next 10 years It constitutes a complex task, requiring
the collaboration of experts from different fields. In future years, we intend to tackle this question
from different angles: on the theory side, we intend to propose a shift in the security objective
towards everlasting security, and demonstrate how this can make the security certification of key
establishment based on QKD combined with ephemeral post-quantum cryptography primitives

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Inria Annual Report 2023

much more tractable. On the system engineering side and in resonance with Section 3.2, we intend
to identify and close implementation security gaps in modern CV-QKD systems relying on digital
signal processing, notably the complex interplay between calibration procedure and finite-size
security, but also between Nyquist pulse shaping and leakage.

3.2 Research axis 2: Multimode photonic systems for quantum information

processing and communications

Building a quantum processor that we could use to solve real-world problems with practical
benefits might constitute one of the most burning scientific and technological challenges of the
beginning of the 21st century. Very interestingly, recent results indicate that quantum optical circuits
constitute a very promising approach for quantum information processing, in particularly high-
dimensional linear optics systems, which can form a (weaker) non-universal quantum computing
platform, and yet efficiently perform tasks intractable for a classical computer, such as Boson
Sampling [17].

We will actively investigate new theoretical questions related to quantum information pro-
cessing with high-dimensional photonic system, and their interplay with technology and experi-
ments.

3.2.1 Quantum coherent communications and digital signal processing

Quantum Key Distribution (QKD) systems are among the most advanced quantum communica-
tions technologies available today. QKD therefore provides an ideal platform to test novel system
designs and validate quantum communication technology over real networks Leveraging essential
features of modern optical communication systems, and in particular high sampling rates and
digital signal processing [43], quantum coherent communications systems constitute a recent and
promising route towards high-rates, highly integrated and cost-effective quantum communic-
ation systems. They rely on two central ingredients: -Spectrally efficient modulation formats
and coherent detection, exploiting phase and intensity information and able to operate a very
high rates (> GHz) even with shot-noise limited receivers. - Digital signal processing that takes
advantage of the high sampling rates to digitally evaluate and compensate many impairments of
the communications such as optical carrier phase noise or polarization mode dispersion, using
dedicated algorithms.

In collaboration with Prof. Yves Jaouen from the GTO team of Telecom Paris,and working
on a state-of-the-art experimental platform, QURIOSITY has designed and demonstrated for the
first time DSP-enhanced quantum communications, with noise control performances that allow
to successfully run QKD over metropolitan distances while being jointly deployed over classical
coherent optical link [21]. We have also filed a patent about this general concept and our inventive
system design.

In the future, we then aim to leverage digital signal processing and machine learning (ML)
techniques to characterize and mitigate noise in order to push further our ability to operate
quantum communications over existing optical fibers, in coexistence with classical signals.

As a complementary line of research, we intend to theoretically study multimode quantum
coherent communications using multimode shaping of the local oscillator, taking inspiration from
[30]. We also intend to explore the possibility to rely on CV multimode encoding as a way to
experimentally implement new quantum cryptographic constructions in the hybrid quantum
computational security models introduced in Section 3.1.

3.2.2 Quantum information processing with a programmable frequency processor

In collaboration with the teams of Nadia Belabas and Pascale Senellart at C2N and in the context of
the ParisQCI project, we study how to combine high-dimensional photonic gates in the frequency
domain, to efficiently synthesize high-dimensional unitary transformations. Leveraging on the
possibility to parallelize single-qubit unitaries, that we have recently analyzed [5] we intend to

Project QURIOSITY

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study how such systems could be leveraged for optical quantum information processing, and in
particular for quantum metrology. In the future, we will also investigate how to scale the platform
to perform information processing with high-dimensional quantum states, opening the possibility
to achieve quantum computational advantage, but also implementation routes for the hybrid
quantum-computational cryptographic protocols in the QCT model, studied in Section 3.1

Figure 2: Multimode programmable linear optical circuit and associated experimental devices
(Spatial Light Modulators: SLM, Multimode fibers: MMF, Detection of single photons multipixel
APDs). This experimental platform, implemented, at the international state of the art in the
team of Sylvain Gigan, at LKB, allows to create, in a programmable way, an arbitrary unitary
transformation on quantum states of light, in high dimension. (Credit: Complex Quantum Optics
team, LKB, ENS Paris).

3.2.3 Quantum information processing using multimode programmable linear circuits

In collaboration with the team of Sylvain Gigan at ENS Ulm, and in the context of Francesco
Mazzoncini’s PhD that we co-supervise, we aim to use a multimode programmable linear circuit,
built around a multimode fiber (cf. Figure 2) to perform some fundamental tests and demonstra-
tions of quantum communication advantage, related to fundamental problems such as the Vector
in a Subspace [48].

The prospects of this work are very promising: first they could lead to the first experimental
demonstration of a exponential communication complexity gap between one-way quantum com-
munication and two-way classical communications and may also open towards the possibility for
experimentally robust Bell inequality violations [45], with applications for quantum cryptography
and also in quantum computing.

3.3 Research axis 3: Mathematical foundations of quantum information

Quantum information and computation are built upon the mathematical frameworks of functional
analysis and information theory. Developing our understanding of the mathematical underpin-
nings of these theories can in turn lead to new insights and applications. At QURIOSITY, one of our
aims is to explore quantum information theory through the lens of the underlying mathematics. In
a nutshell, we will parallelly develop new analytic and numerical tools for the study of quantum
entropic quantities and complex quantum systems made of spin or bosonic degrees of freedom.
We will in turn consider these systems to design new, physically motivated models of noise-robust
quantum computing.

3.3.1 Convex relaxations of quantum optimization problems

Convex optimization concerns the optimization of convex functions over convex sets. This family
of optimization problems has several particularly nice properties, including the guarantee of global
optima, which makes them particularly appealing from both the perspective of the mathematics
and the applications. They are widely applicable to many domains of science but in particular
they arise rather naturally in the context of quantum theory as many of the relevant objects (states,
channels and measurements) form convex sets.

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Inria Annual Report 2023

We will aim to develop and apply techniques in convex optimization theory to problems
within quantum information and quantum computing. Recent examples of our work in this
area include [28, 29] where we developed semidefinite programming relaxations for entropic
optimization problems relevant to device independent cryptography. Continuing this line of
research we aim to extend these techniques to other entropic quantities beyond the relative entropy,
for instance to the Petz and sandwiched families of Rényi divergences. We also have the ambitious
goal of understanding and characterizing what classes of functions, relevant in the context of
quantum theory, are amenable to such semidefinite programming approximations. In other words,
what optimization problems in quantum information theory and quantum computing can we
approximate?

A well-known example concerns strengthenings of the monotonicity of the relative entropy
under the action of a quantum channel or a Markovian evolution known as strong data processing
and modified logarithmic Sobolev inequalities. These fundamental inequalities are known to be
hard to prove analytically, even for simple random walks on n-cycles, and convex relaxation tech-
niques were recently successfully used to approximate them [37]. We are currently collaborating
with Omar Fawzi and Daniel Stilck França from QINFO to adapt these numerical tools to the
quantum realm. In the future, we will consider extending these tools to the infinite dimensional
bosonic setting in order to approach long-standing conjectures such as the entropy photon number
inequality [39]. This research direction will complement analytic approaches presented in Section
3.3.2.

3.3.2 Fundamental properties of entropies

Entropies are fundamental quantities in quantum information theory, obtaining operational mean-
ings in terms of rates of various tasks [36]. By improving our understanding of these quantities,
we can in turn gain new insights into the various applications in which they appear.

For example, new chain rules for Rényi entropies [35] led to a versatile framework for crypto-
graphic security proofs [20]. The result, known as the entropy accumulation theorem, effectively
gives sufficient conditions under which the entropy of a large system can be accurately described
by the entropy of its individual systems. At QURIOSITY we aim to understand under which
conditions does entropy accumulate in this manner? By understanding the minimal require-
ments for entropy to accumulate we can understand the minimal requirements under which a
randomness based cryptographic protocol functions securely. Moreover, we aim to investigate
the connection between the entropy accumulation theorem and the related works of the quantum
probability estimation framework [57]. This is an alternative method to break large entropies down
into smaller quantities and reports several advantages over the entropy accumulation theorem.
Understanding how advantages from one technique can be transferred to the other will lead to
much stronger theoretical results and would have immediate applications to improve security
proofs and rates of cryptographic protocols, leading to more practical technologies.

Other types of decompositions of entropic quantities of interacting complex systems into
smaller components involving marginals over subsystems include generalizations of the famous
strong subadditivity of the relative entropy known as approximate tensor-stability of the relative
entropy. These are at the core of most successful methods for finding the speed of convergence
of Gibbs sampling algorithms based on the modified logarithmic Sobolev inequality. In previous
work, we successfully extended these notions to the quantum realm [38] and applied them to
problems in network quantum information theory [25, 33] and open complex quantum systems
[31, 22]. Extensions and refinements of these concepts will lead to new breakthroughs in both
fields (see Sections 3.3.3 and 3.3.4).

3.3.3 Complexity and entanglement properties of quantum Gibbs states

A complexity theoretical definition of the quantum phase of a state ψ consists in taking the vicinity
of states which are reachable from ψ after applying a local evolution during a short period of time.
A topologically ordered phase has the property that the time required to reach it starting from a
trivial (i.e. product) state scales extensively with the system size. In other words, topological order

Project QURIOSITY

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can be described in terms of circuit depth lower bounds. The classification of quantum phases of
matter is by now a very well-established field with far-reaching applications e.g. to the construction
of good quantum error-correcting codes exploiting the properties of topologically ordered phases.
However, a more realistic description of a quantum mechanical system is in terms of a finite
temperature Gibbs state describing its thermal equilibrium with a large environment. Despite their
practical relevance, until recently Gibbs states were primarily studied by mathematical physicists,
and many fundamental questions regarding their use in quantum information processing remain
open. We propose to investigate the complexity of quantum Gibbs states through the scope of their
finite temperature phase transitions. Additionally to its fundamental value, this research direction
will undoubtedly lead to several important practical applications, as described in section 3.3.4.

In the setting of classical Gibbs measures, analogous questions have been intensively studied
from the perspective of Markov chain Monte Carlo algorithms (MCMC). On regular lattices, the
analysis of the speed of convergence of MCMC for lattice spin systems is by now well-understood
through the study of correlations at equilibrium. The generalization to general interaction graphs
is still a very active field of research in theoretical computer science, probability theory and
mathematical physics [32]. The problem becomes even harder in the quantum regime, where
purely quantum mechanical effects, e.g. long-range entanglement, may cause the quantum Markov
chain to slow down in an unpredicted manner. For the important case of commuting interactions,
which include most hitherto studied Hamiltonians for the purpose of quantum error-correction,
and for physical dynamics generated by the weak coupling of the system with a large environment
(Davies dynamics), general results were obtained through spectral methods. However the latter
are not powerful enough to distinguish evolutions generating topologically ordered states from
rapidly mixing ones. Instead, more involved techniques, e.g. entropic inequalities, are needed.
In [24, 31, 23, 22], we were able to prove rapid mixing by extending one of the most successful
classical approaches to prove rapid mixing based on the modified logarithmic Sobolev inequality
and the approximate tensor-stability of the relative entropy (cf Section 3.3.2). Extending this novel
powerful approach, we plan to conduct a systematic joint study of mixing times and thermal
stability of topological quantum order in low lattice dimensions. We will conduct this research in
collaboration with Daniel Stilck França from QINFO with whom we co-authored [31]. We also see
a clear connection with the research focus of Daniel Malz who was recently recruited as a junior
professor at Inria Saclay, the mathematical and theoretical condensed matter physicists at CPhT, as
well as the team PEIPS at CMAP (X).

3.3.4 Mathematical analysis of quantum memories

In parallel to the previous research plan, we will conduct a mathematical analysis on the storage of
quantum information and the concept of self-correction in complex quantum systems. Early work
on the storage time of candidates of self-correcting quantum memories relied on the connection
to the energy barrier of the system, that is the energy the system must reach for a logical error to
occur, via an empirical principle called the Arrhenius law. More recently, the energy barrier was
rigorously related to spectral properties of the evolution, whereas some no-go theorems showed
the impossibility of an exact mathematical formulation of the Arrhenius law. Here instead, we
plan to relate the memory lifetime of a device directly to properties of its thermal equilibrium state.
We currently work on this research direction in the setting of lattice spin systems with Anthony
Leverrier and Ivan Bardet from the team COSMIQ through the development of spectral methods,
and plan to extend our framework to lattices with bosonic degrees of freedom in the near future.
We also plan to initiate a dialogue with Jean-René Chazottes from CPhT (X) on refinements of our
techniques using concentration and entropic inequalities which already proved their usefulness
in the study of hitting times of classical Markov chains and their metastability. One of our long–
term goals is to find systems with thermally stable entanglement, both stable against thermal
fluctuations and robust against local perturbations. Such a theoretical result would be of very high
practical interest since experimental implementations are inevitably subject to noise and errors.

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Inria Annual Report 2023

3.3.5 Tomography of complex quantum systems

As the size of quantum devices continues to increase beyond what can be easily simulated clas-
sically, new challenges have appeared concerning the robust and efficient characterization of
their states. This often necessitates the preparation and destructive measurement of exponen-
tially many copies of the quantum system, as well as the storage of measurement outcomes in a
classical memory. Recently, new methods of tomography have been proposed which precisely
leverage this important simplification to develop efficient state learning algorithms. One highly
relevant development in this direction is that of classical shadows [41, 42]. In we propose a better
solution by combining classical shadows with new insights from the emerging field of quantum
optimal transport. Our current first step only applies to topologically trivial quantum states
such as high-temperature Gibbs states or outputs of shallow quantum circuits, and more effort
is needed to adapt and generalize our algorithm to non-trivial phases. We envision three new
major contributions: First, we will develop constrained versions of concentration inequalities in
order to develop efficient tomography algorithms of complex quantum states, assuming the prior
knowledge of their phase. This line of research is original even in the classical setting where works
on constrained entropic inequalities only very recently appeared in the literature. The expertise of
Jean-René Chazottes from CPhT (X) will prove crucial to the success of this project. Second, we
will extend the framework of shadow tomography to CV quantum systems. The main difficulties
here are two-fold: first, CV systems are infinite-dimensional in nature, and hence some physical
constraints need to be imposed on the states that one can hope to learn, such as their energy.
Moreover, the set of measurements (homodyne/heterodyne) available in photonic experiments
further limits the type of observables that one can hope to predict. In order to ensure the wide
applicability of the method and test the resulting algorithm, we will rely on the already established
interactions of IQA with the groups of experimentalists at IP Paris and Saclay, and initiate a fruitful
dialogue with start-up like Quandela and Pasqal. In the future, we will use these methods to
devise hardware-oriented noise-learning algorithms for many-body systems. For this, we plan to
get in touch with the experts on statistical learning among IP Paris, and in particular at LIX.

3.3.6 Formal tools for higher-order quantum computation

The theoretical study of quantum computation and its advantages has, in the past decade, opened
to a new perspective: higher-order quantum computation, i.e. the way in which one can transform
black-box quantum gates by inserting them into computation architectures. This is useful to
study the ways in which one can query subroutines in quantum computation, a pratice that
is bound to become ubiquitous, for example in delegated quantum computing. The study of
higher-order quantum computation has already led to promising as well as disconcerting results,
such as about the difficulty of formally defining a quantum version of the computational ‘if’
clause [19], or the fact that one might be able to query two unknown gates in a ‘superposed
order of application’, using a computation architecture called the quantum switch [34]. Using
the latter leads to computational advantages for certain tasks [18]. However, the mathematical
study of higher-order quantum processes quickly encounters thorny formal issues related to their
non-trivial compositional structure.

Overcoming these issues would require the development of a specific and robust type system,
stipulating which inputs a given higher-order quantum process admits and which output it
produces. Despite recent advances [44], currently available type systems are not detailed enough to
provide a fully compositional view of higher-order quantum computation. Our work thus focuses
on refining them, through the encoding of sectorial structure, i.e. information about how quantum
channels behave with respect to certain direct-sum decompositions of their input and output
spaces, using the recently developed framework of routed quantum circuits [53, 54]. Progress in
this direction will pave the way to computer manipulation of complex higher-order processes, for
instance to numerically optimise the advantage they yield.

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3.3.7 Causal structure in quantum theory

Many of the peculiarities of quantum theory can be tracked down to it not matching our classical
notion of causal structure [55]; this leads to the question of how one could develop a quantum
notion of causal structure, on which some progress has been achieved recently [26]. Exploring
quantum theory from a causal perspective yields potential progress in understanding its structure
and potential applications, in particular for the aforementioned higher-order quantum processes,
whose performances are directly connected to their causal structure. In that regard, a particularly
important conjecture to prove is that of causal decompositions [46], which puts forward a tentative
equivalence between a unitary channel’s causal structure (operational data about which of its
inputs can affect which of its outputs) and its compositional structure (mathematical data about
how it can be written as the composition of sub-channels). If such a conjecture (which has not been
proven yet in the general case) were to be true, it would yield a remarkable mathematical lever on
the relationship between the operational and formal sides of quantum theory. We investigate this
conjecture mathematically with the aim to prove it in more and more general cases; this involves
abstract mathematical methods employing C* algebras. More generally, we explore how the latter
might provide a useful formal basis for considerations of causality in a quantum context.

4 Application domains

QURIOSITY positions its activity at the - fruitfull - frontier between theoretical research in quantum
computer science and mathematics, and quantum technology engineering and applications.

We in particular believe that useful quantum inventions and technologies are going to emerge
from the current investments in quantum information sciences and technologies, much before
large scale (and error corrected) quantum computers can be built.

Our research programs opens in particular towards such perspective, on different aspects:

• The development of more efficient and higher security quantum cryptographic protocols.

• The ability to leverage quantum cryptography principles and tecnnologies to strengthen

hardware security.

• The design of cost-effective quantum communications systems that can tightly integrated

into modern communication infrastructures, making them widely deployable.

• The design of better quantum memories and therefore larger quantum computer as well as

quantum networks.

5 Social and environmental responsibility

5.1 Footprint of research activities

QURIOSITY members are individually, and collectively making efforts to reduce their carbon
footprint, in particular by taking the plane much less than before the Covid period. Augustin Van-
rietvelde and Peter Brown will moreover act as carbon footprint delegates for QURIOSITY, and
report to a working group at LTCI level, whose objective will be to increase the global awareness
on carbon footprint, and steer the discussions to help decide on collective regulatory measures.

5.2

Impact of research results

Scientific publication QURIOSITY aims at publishing high-impact papers in high profile journals
such as Nature, Science, Physical Review, Quantum, IEEE Transactions on Information Theory, as
well as top conferences in our field such as QIP, QCrypt, TQC as well as Crypto, EuroCrypt, CHES.

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Inria Annual Report 2023

Innovation Telecom Paris currently holds 5 granted patents: 3 on hybrid quantum computa-
tional cryptography (axis 3.1) and 2 on quantum coherent communications (axis 3.2). We plan
to patent technological innovations, including foundamental proposals for which we see a clear
implementation route and possible exploitation paths.

Teaching QURIOSITY intends to play a vigorous role in the training of the future generation of
quantum engineers and researchers. IQA and Romain Alléaume have been at the forefront of such
development by opening the Quantum Engineering M2 Program in 2017. At Saclay level, and in
collaboration notably with the QuACs Inria team but also with active Saclay quantum industry,
we have the mid-term ambition to launch a master program on quantum computer science and
engineering.

6 Highlights of the year

6.1 Five papers selected at QIP 2024

After less than a year of existence QURIOSITY has obtained oustanding results at QIP 2024 in terms
of selected contributions, with 4 members of QURIOSITY that are co-authors of 5 accepted papers:

1. Thomas van Himbeeck and Peter Brown. A tight and general finite-size security proof for

quantum key distribution.

2. Jan Kochanowski, Alvaro Alhambra, Ángela Capel and Cambyse Rouzé. Spectral gap implies

rapid mixing for commuting Hamiltonians

3. Robert König and Cambyse Rouzé. Limitations of local update recovery in stabilizer-GKP

codes: a quantum optimal transport approach.

4. Emilio Onorati, Cambyse Rouzé, Daniel Stilck Franca and James Watson. Efficient learning

of ground and thermal states within phases of matter.

5. Emilio Onorati, Cambyse Rouzé, Daniel Stilck França and James Watson. Provably Efficient

Learning of Phases of Matter

6.2 Awards and Grants

Starting Packages Cambyse Rouzé, Mirjam Weilenmann and Augustin Vanrietvelde have each
been awarded a starting package in the context of the ANR ExcellenceS Program, on the STEP2
project sucessfully presented by IP Paris.

Best Poster Award Tristan Nemoz has been granted the Best Poster Award (category Information
Communication Electronics) at IP PAris PhD Day, on December 10 2023.

6.3 Quantum Hardware Security Workshop

The 2-day workshop held at University of Edinburgh on Novepber 23-24 and organized between
QURIOSITY (Romain Alléaume, Peter Brown, Francesco Mazzoncini, Tristan Nemoz) and the team
of Elham Kashefi at Quantum Software Lab (Elham Kashefi, Mina Doosti, Myrto Arapinis, Yao Ma,
Abbas Poshtvan, Chrirag Wadhwa) has been extremly fruitful both scientifically and in the quality
and friendlyness of the exchanges. We can see strong convergence, and possible synergies and
collaborations, between our visions of the role that Quantum Cryptography can play in Hardware
Security, as also expressed in 3.1 )

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13

7.1 Research axis 1: Quantum cryptography complexity and hardware frontiers

7.1.1 Prove the security of hybrid quantum-computational cryptographic protocols by a reduc-

tion to a quantum to classical communication complexity gap

Participants: Romain Alléaume, Peter Brown, Francesco Mazzoncini.

In [11], we introduce an explicit construction for a key distribution protocol in the Quantum
Computational Timelock (QCT) security model, where one assumes that computationally secure
encryption may only be broken after a time much longer than the coherence time of available
quantum memories. Taking advantage of the QCT assumptions, we build a key distribution
protocol called HM-QCT from the Hidden Matching problem for which there exists an exponential
gap in one-way communication complexity between classical and quantum strategies. We establish
that the security of HM-QCT against arbitrary i.i.d. attacks can be reduced to the difficulty of
solving the underlying Hidden Matching problem with classical information. Legitimate users,
on the other hand, can use quantum communication, which gives them the possibility of sending
multiple copies of the same quantum state while retaining an information advantage. This leads
to an everlasting secure key distribution scheme over n bosonic modes. Such a level of security
is unattainable with purely classical techniques. Remarkably, the scheme remains secure with
√
up to
log(n) input photons for each channel use, extending the functionalities and potentially
outperforming QKD rates by several orders of magnitudes.

n

7.1.2 New self-testing constructions for device-independent cryptography

Participants: Lewis Wooltorton, Peter Brown, Roger Colbeck.

In [16, 15] we developed new constructions to certify properties of quantum systems using
Bell-tests. In [16] we provide a method to stitch together bipartite Bell-inequalties to construct
useful multipartite Bell-inequalities. We show that these new inequalities inherit certain self-testing
prop erties of the original inequalities and we use this to produce protocols that achieve maximal
device-independent randomness generation. In [15] we explore the complicated relationship
between nonlocality and secret-key, showing that perfect secret key-rates can be achieved in
device-independent quantum key distribution protocols with correlations that are arbitrarily close
to classical. This involves developing a compact expression of a parameterized Bell-inequality that
represents all possible self-tests of the maximally entangled state

7.1.3 Tight finite-size security proof for quantum key distribution protocols

Participants: Thomas Van Himbeeck, Peter Brown.

We have developed a new security proof framework for standard quantum key-distribution
(QKD) protocols. The framework is: (i) generic, applying to all possible round based QKD
protocols; (ii) tight, providing key-rates that are optimal for any given finite number of rounds
up to leading order correction and (iii) computable, we develop convex optimization methods
to compute the key-rates. This is achieved in part through the development of new entropic
quantities that enable tight accounting of finite-size corrections. We expect the work to have
significant impact on the future development of QKD protocols and security proofs.

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Inria Annual Report 2023

7.2 Research axis 2: Multimode photonic systems for quantum information

processing and communications

7.2.1 Quantum Coherent Communication and Digital Signal Processing

Participants: Romain Alléaume, Gjuillaume Ricard, Nicolas Fabre,

Thomas Pousset, Yves Jaouën.

Building up on [21], we are performing a systematic analysis and model of excess noise in
a quantum coherent communication channel, jointly operated with a classical coherent channel,
taking into account the effect of digital signal processing. We are moreover validating our results
with digital simulation along with experimental system demonstration. We are moreover studying
how Kramers-Krönig coherent detection can be used in quantum communications.

7.2.2 Parallelizable Synthesis of Arbitrary Single-Qubit Gates with Linear Optics and Time-

Frequency Encoding

Participants: Romain Alléaume, Guillaume Ricard, Antoine Henry, Nadia Bela-

bas.

In [5], we propose novel methods for the exact synthesis of single-qubit unitaries with high
success probability and gate fidelity, considering both time-bin and frequency-bin encodings.
The proposed schemes are experimentally implementable with a spectral linear-optical quantum
computation (S- LOQC) platform, composed of electro-optic phase modulators and phase-only
programmable filters (pulse shapers). We further investigate the parallelization of arbitrary single-
qubit gates over multiple qubits with a compact experimental setup, both for spectral and temporal
encodings. Our analysis positions spectral S-LOQC as a promising platform to conduct massively
parallel single qubit operations, with potential applications to quantum metrology and quantum
tomography.

7.2.3 Limitations of GKP-LDPC concatenated codes

Participants: Robert König, Cambyse Rouze.

In [10], we established an analytic upper bound on the fault-tolerance threshold for concaten-
ated GKP-stabilizer codes with local update recovery. Our bound applies to noise channels that
are tensor products of one-mode beamsplitters with arbitrary environment states, capturing, in
particular, photon loss occurring independently in each mode. It shows that for loss rates above a
threshold given explicitly as a function of the locality of the recovery maps, encoded information
is lost at an exponential rate.

7.3 Research axis 3: Mathematical foundations of quantum information

7.3.1 Higher-Order quantum computation

Participants: Augustin Vanrietvelde, Octave Mestoudjian.

We are developing fine-grained type systems for the certification of quantum computation
architectures, in particular those involving quantum control (quantum versions of the "if" clause)
and indefinite causal order (application of operations in a superposed order).

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7.3.2 Causal models in quantum theory

Participants: Augustin Vanrietvelde, Pablo Arrighi, Octave Mestoudjian.

We are investigating the relationship (and in particular the potential equivalence) between the
causal structure of quantum dynamics and their compositional structure. We are finishing a proof
(to be published soon) that there is an equivalence between the two in the case of local dynamics
over a 1D array of quantum systems, at any range.

7.3.3 Learning complex quantum states

Participants: Marco Fanizza, Niklas Galke, Josep Lumbreras, Cambyse Rouzé,
Andreas Winter, Emilio Onorati, Daniel Stilck França, James D
Watson, Tim Möbus, Andreas Bluhm, Matthia C Caro, Abert H
Werner, Cambyse Rouzé.

In [12, 12, 13, 27], we have developed robust, sample and computationally efficient quantum
algorithms for tomography and learning of states and noise on many-body discrete and continuous
variables quantum systems, including thermal and ground states of spin and Bosonic Hamiltonians,
finitely correlated states, and Pauli noise channels with unknown underlying local structure.

7.3.4 Complexity of quantum Gibbs states

Participants:

Ivan Bardet, Ángela Capel, Li Gao, Angelo Lucia, David Peres-
García, Cambyse Rouzé, Jan Kochanowski, Alvaro Alhambra,
Paul Gondolf.

We have kept on working on the complexity of Gibbs sampling algorithms and its applications
to the stability of quantum simulation and the characterization of self-correcting quantum memor-
ies [22], [23]. In particular, we have extended our previous result on the rapid mixing of Gibbs
samplers from 2-local to k-local interacting systems (the article is being finalized). In particular,
we resolved an old open problem, namely whether the existence of a dissipative gap implies
rapid mixing of the thermalization process. As regards to applications to quantum memories,
our result implies that the entire class of quantum double models (including the 2D Toric code)
reaches thermal equilibrium in logarithmic time, while the previous best thermalization time
scaled linearly with the system size.

7.3.5 Improved quantum algorithm design from polynomial optimization

Participants: Thomas Van Himbeeck, Peter Brown.

A recently developed quantum algorithm known as the Quantum Singular Value Transform
(QSVT) was shown to encompass the standard quantum algorithms, Shor/Grover etc., as special
cases. Using the fact that the QSVT provides a correspondence between polynomials and certain
families of quantum circuits, we develop methods to optimize these circuits (and hence the
resulting algorithms) in terms of polynomial optimization and its resulting SDP relaxations. We
also show to scale up these optimizations to large-scale circuits, demonstrating its usefulness at
scales necessary for quantum advantage.

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Inria Annual Report 2023

8 Bilateral contracts and grants with industry

8.1 Bilateral contracts with industry

Orange Innvovation

Participants: Romain Alléaume, Yves Jaouën, Guillaume Ricard, Pierre-

Enguerrand Verdier.

• CIFRE with Orange Innovation (Chatillon) on Discrete Variable Quantum Key Distribution

and Time Multiplexing, PhD Student: Pierre-Enguerrand Verdier.

• CIFRE with Orange Innovation (Lannion) on Continous Variable Quantum Key Distribution

and Wavelenght Division Multiplexing, PhD student: Marco Andersohn.

8.2 Grants with industry

Paris Region PhD Grant, collaboration with Quandela Doctoral project of Guillaume Ricard,
on Quatum Coherent Communications and Digital Signal Processing, Funded by Paris funded
by Paris Region (region Ile-de France) in the context of the Paris Region PhD call, with a planned
collaboration with Quandela on noise mitigation in optical coherent quantum communications.

9 Partnerships and cooperations

9.1 European initiatives

9.1.1 Horizon Europe

Quantum Secure Network Partnership

Participants: Romain Alléaume, Peter Brown, Tristan Nemoz, Francesco Mazzo-
ncini, Guillaume Ricard, Thomas Van Himbeeck, Thomas Pousset,
Nicolas Fabre, Yves Jaouën.

Partner Institutions: The Quantum Secure Networks Partnership (QSNP) aims at creating a sus-
tainable European ecosystem in quantum cryptography and communication. Its 42 partners
are world-leading academic groups, research and technology organizations (RTOs), quantum
component and system spin-offs, cybersecurity providers, integrators, and telecommunica-
tion operators. The Partnership thus has the expertise in all technology development phases,
from new designs to field deployment, making it ideal to carry out the future Specific Grant
Agreement (SGA) projects.

1. ICFO-The Institute of Photonic Sciences, Spain, (Coordinator)

2. Centre National de la Recherche Scientifique, France

3. Institut Polytechnique de Paris, France

4. Technical University of Denmark, Denmark

5. Universidad Politécnica de Madrid, Spain

6. Friedrich-Alexander University Erlangen-Nuremberg, Germany

7. QuTech, at the Technical University Delft, Netherlands

8. Università di Padova, Italy

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9. AIT Austrian Institute of Technology, Austria

10. Palacky University Olomouc, Czech Rep.

11. Instituto Superior Técnico, Portugal

12. Universidade de Vigo, Spain

13. Katholieke Universiteit Leuven, Belgium

14. Universität Wien, Austria

15. Université libre de Bruxelles, Belgium

16. University of Warsaw, Poland

17. University of Malta, Malta

18. Institute of Communications and Computer Systems, Greece

19. Universität Paderborn, Germany

20. Inria Cosmiq team, France

21. National and Kapodistrian University of Athens (NKUA),Greece

22. Instituto De Telecomunicacoes, Portugal

23. Politecnico di Bari, Italy,

24. Fraunhofer Heinrich-Hertz-Institut, Germany

25. Commissariat à l’Energie Atomique et aux Energies Alternatives, France

26. Technische Universiteit Eindhoven, Netherland

27. Interuniversity Microelectronics Centre, Belgium

28. University College Cork, Ireland

29. QuSide, Spain

30. LuxQuanta, Spain

31. Micro Photon Devices, Italy

32. ThinkQuantum, Italy

33. VPIphotonics GmbH, Germany

34. Alea Quantum Technologies ApS, Denmark

35. Q*Bird, Nertherlands

36. Cryptonext Security, France

37. Nokia Bell Labs, France

38. Nextworks, Italy

39. Deutsche Telekom, Germany

40. Telefónica, Spain

41. TIM S.p.A, Italy

42. Orange SA,France

Contract ID: HORIZON-CL4-2022-QUANTUM-04-SGA

Information on the Contract: Special Grant Agreement in the context of a Federated Grant Agree-
ment related to the Quantum Communications Pillar of the European Quantum Technology
Flagship.

Duration: March 2023 – August 2026

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Inria Annual Report 2023

Description: The Quantum Secure Networks Partnership (QSNP) is structured around three main
Science and Technology (ST) pillars. The first two pillars, “Next Generation Protocols” and
“Integration”, focus on frontier research and innovation led mostly by academic partners and
RTOs. The third ST pillar “Use cases and Applications” aims at expanding the industrial
and economic impact of QSN technologies and is mostly driven by companies. In order
to achieve the specific objectives within each pillar and ensure that know-how transfer
and synergy between them are coherent and effective, QSNP has established ST activities
corresponding to the three main layers of the technology value chain, “Components and
Systems”, “Networks” and “Cryptography and Security”. Future SGA projects will be able
to efficiently rely on this framework, in such a way that the ultimate objective of developing
quantum communication technology for critical European infrastructures, such as EuroQCI,
and private information and communication market sectors, will be achieved. QSNP will
contribute to achieving European sovereignty in quantum technology for cybersecurity. At
the same time, it will generate significant economic benefits to the whole society, including
training a new generation of scientists and engineers, and the creation of high-tech jobs in
the rapidly growing quantum industry.

Role of QURIOSITY: QURIOSITY has important participations on Quantum Coherent Commu-
nications System Design (WP2), Theory of Quantum Cryptography and in particular on
Device-Independent Quantum Crypography (WP3), Hybrid Quantum-Computational Cryp-
tography (WP4 and WP6).

• Romain Alléaume leads one of the 3 pillars of the project, devoted to Integration (at
hardware, middleware and cryptographic applications levels) and is member of the
Executive Board of QSNP

• Romain Alléaume leads WP6 on Quantum and Classical Cryptography Integration.

• Romain Alléaume leads IP Paris contribution to WP4 on Quantum Cryptographic

Protocols beyond QKD.

• Peter Brown leads IP Paris contribution to WP3 on Device-Independent QKD and

QRNG.

• Several teams from IP Paris participates to the project: QURIOSITY, GTO, C2 at Telecom

Paris and GRACE at LIX/Ecole Polytechnique.

9.1.2 Digital Europe

FranceQCI

Participants: Romain Alléaume, Peter Brown, Tristan Nemoz, Francesco Mazzo-
ncini, Guillaume Ricard, Thomas Van Himbeeck.

Partner Institutions:

1. Orange SA,France (Coordinator)

2. Institut-Mines-Telecom (IMT), France

3. Airbus Defense and Space, France

4. Thales SIX, France

5. CryptoNext Security, France

6. CNRS, France

7. Thales Alenia Space, France

8. CNRS Université Cote d’Azur, France

9. Sorbonne Université, France

10. WeLinQ SAS, France

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11. VeriQloud, France

12. Direction des Services de la Navigation Aérienne, DSNA, France

Contract ID: Project: 101091675 — FranceQCI — DIGITAL-2021-QCI-01

Information on the Contract: Call DIGITAL-2021-QCI-01-DEPLOY-NATIONAL, Topic 1 from the

Digital Europe Call on Quantum Communication Infrastructures.

Duration: January 2023 – June 2025

Description: The objective of the project is to test use cases of quantum communication tech-
nologies and to deploy advanced national quantum systems with existing communication
networks in support of national QCI initiatives.

Role of QURIOSITY: Quriosity, represented as IMT, contributes to network design and deploy-
ment (WP2), to security studies (WP3), and leads the activity on training (WP7) by coordinat-
ing the first executive education training offfer (in France) on quantum communication and
cryptography, in collaboration with Sorbonne University and Orange Innovation.

9.1.3 Other european programs/initiatives

PETRUS

Participants: Romain Alléaume.

Partner Institutions:

1. Deutsche Telekom

2. Airbus Defense and Space, France

3. Thales SIX, France

4. Austrian Institute of Technology, AIT, Austria

Contract ID: DIGITAL-2021-QCI-01 Digital European Program under grant agreement no. PET-

RUS 101091719.

Information on the Contract: PETRUS is the Coordination and Support Action for the national

Quantum Communication Infrastructures.

Duration: July 2023 – December 2025

Description: The European Quantum Communication Infrastructure (EuroQCI)is to be rolled
out in the EU Member States over the coming years. PETRUS supports the Digital Europe
Program projects that aim to form the basis for a European industrial ecosystem for secure
quantum technologies. PETRUS brings together former consortium leaders of the most relev-
ant studies and projects on EuroQCI, bundles their experience and expertise and includes
top experts from industry and the academic quantum community.

Role of QURIOSITY: Romain Alléaume acts as Scientific Expert for the project.

9.2 National initiatives
PEPR QCommTestbed

Participants: Romain Alléaume, Peter Brown, Nicolas Fabre, Yves Jaouën,

Tristan Nemoz, Thomas Pousset, Thomas Van Himbeeck.

Partner Institutions:

1. Institut-Mines-Telecom (IMT), France

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Inria Annual Report 2023

2. CNRS Université Cote d’Azur, France

3. Sorbonne Université, France

4. CEA Leti, France

5. C2N, France

6. Université Paris-Cité, France

Contract ID: PC 4.3 « QCommTestbed » (Quantum communication testbeds)

Duration: 01/07/2022 – 30/06/2027

Description: The objective of the QcommTestbed project is to lay the foundations for fiber optic
and free-space quantum networks on a regional and longer-term national scale, making
it possible to connect systems including quantum elements (transmitters and receivers,
processors, sensors) via repeater nodes. The project also aims to make decisive advances
in the TRL of quantum communication systems, and also in their security evaluation and
testing, to pave the way for their wider adoption and ubiquituous deployment.

Role of QURIOSITY:

• Demonstration of ITS secure communication over a single fiber, based

on joint CV-QKD and classical communication integration.

• Performance and Cost of Long-Term Secure Storage based on CV-QKD

• Vulnerability analysis of a QKD (VAN) system. Definition of an evaluation methodology

(based on the Common Criteria.

• Experimental Demonstration of Mulimode Frequency-encoded Key Distribution in the

QCT model

9.3 Regional initiatives

ParisRegionQCI

Participants: Romain Alléaume, Francesco Mazzoncini, Thomas Van Himbeeck.

Partner Institutions:

1. Orange SA,France (Coordinator)

2. LTCI, Telecom Paris, France

3. Thales SIX, France

4. Thales Research and Technology (TRT), France

5. CryptoNext Security, France

6. CNRS, France

7. LIP6, Sorbonne Université, France

8. VeriQloud, France

9. NOKIA Bell Labs, France

10. Kets Quantum, UK

11. Laboratoire Charles Fabry, France

Information on the Contract: Project funded as a SIRTEQ Synergy action, funded by Paris Region

Duration: January 2021 – Dec 2023

Description: The ParisRegionQCI project revolves around the development and operation of a
fiber network quantum in Paris Region (Île-de-France ). The creation of such a network is
envisaged as part of the project H2020 “OpenQKD”, which is a precursor of the “European
Quantum Communication Infrastructure”, EuroQCI, planned as part of the next framework
program of the European Commission, and which will include terrestrial and space segments.

Project QURIOSITY

21

Role of QURIOSITY: Quriosity, as part of Telecom Paris has been to contributes to network design
and deployment, and to lead the security study, with a focus on the security advantage that
could (or could not) be achieved using QKD, in different cryptographic constructions aiming
to ensure secure communication security services.

10 Dissemination

10.1 Promoting scientific activities

10.1.1 Scientific events: organisation

Member of the organizing committees

• Romain Alléaume member of the organization committee of the LTCI Research Day, Nov 24

2023.

• Romain Alléaume co-organized the Quantum Hardware Security Workshop at Edinburgh,

with the Quantum Software Lab, 22-23 November 2023.

10.1.2 Scientific events: selection

Member of the conference program committees

• Romain Alléaume TPC of TPC IEEE ICC’23 - SAC-11 QCIT Track

• Cambyse Rouzé TPC of QIP 2024

Reviewer

• Romain Alléaume for TQC (subreviewer)

10.1.3 Journal

Reviewer - reviewing activities

• Romain Alléaume for Science Advances

10.1.4 Invited talks

• Peter Brown, Tight finite-size security proof of QKD, 5th edition of security of QKD workshop,

IQC Waterloo, Canada. (September 2023).

• Peter Brown, On the computation of device-independent quantities, 5th edition of security of

QKD workshop, IQC Waterloo, Canada. (September 2023).

• Peter Brown, Tight finite-size security proof of QKD, Workshop on Gaussian and non-

Gaussian Quantum Correlations, Copenhagen Denmark (November 2023).

• Romain Alléaume, Quantum Secure Network Partnership Integration Pillar, CLP Days, ICFO,

Barcelona (25 Mai 2023).

• Romain Alléaume, Slow Information, Workshop On Quantum Ecology, Leyzin Switzerland

(July 2023).

10.1.5 Leadership within the scientific community

• Romain Alléaume is one of the 3 Pillar Leaders, WP6 Leader and a member of the Executive

Board of the Quantum Secure Network Partnership Flagship Project.

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Inria Annual Report 2023

10.1.6 Scientific expertise

• Romain Alléaume, Member of the Alliance Quantum Evaluation Committee, at NSERC, in
charge of scientific evaluation of Canada Quantum Grants Applications (4 sessions per year).

• Romain Alléaume, Member of the Evaluation Committee attributing the Plan Quantique
PHD Grants, for the Paris Centre for Quantum Technologies (Sorbonne University, March 14
2023).

• Romain Alléaume, Member of the Evaluation Committee for IP Paris PhD Track in Qauntum

Science and Technology, February, 14 2023.

• Romain Alléaume, Member of the Evaluation Committee for the admission of Polytecniciens,

at Telecom Paris (double degree)

• Romain Alléaume, Member of the recruitement committee for the position at Ecole Polytech-

nique, Professor Monge in Quantum Computing, May 17, 2023

• Romain Alléaume, Member of the recruitement committee for the Assistant/Associate
Professor position in Quantum Computing and Quantum Information Procesing at Telecom
Paris, May 9, 2023

10.1.7 Research administration

• Romain Alléaume, Member of Comité Directeur of the Network and Computer Science

Departement of Telecom Paris (Infres), acting as Infres Research Delegate, (2023-)..

• Romain Alléaume, Deputy director of Laboratoire de Traitement and Communication de

l’Information LTCI and member of LTCI board (bureau) (2023-).

• Romain Alléaume, Member of Conseil Scientifique du LTCI (2023-).

• Romain Alléaume, Member of Conseil du LTCI (2021-).

• Romain Alléaume, Member of IP Paris IDIA Department bureau, (2023-).

• Romain Alléaume, Member of the Committee in charge of supervising STEP2 program (ANR
ExcellenceS program) funding allocation in Foundation of Computer Science (including
Quantum Computer Science).

• Romain Alléaume is (2020–) an executive committee member of the Quantum center of Saclay.
The center coordinates the French strategy for quantum technologies at the scale of Univ.
Paris-Saclay and Institut Polytechnique de Paris.

10.2 Teaching - Supervision - Juries

All teaching durations are given in hetd = "heures équivalent TD".

10.2.1 Teaching

L3 courses, at Telecom Paris

• Romain Alléaume is teaching in PHY101: Introduction to Quantum Technologies. Courses: 9

hetd ∼110 students, TD: 27 hetd ∼25 students.

• Peter Brown, Francesco Mazzoncini, Tristan Nemoz, Thomas Van Himbeeck, Programming a

real quantum computer, 6+6+6+6 hetd, 9 students.

Project QURIOSITY

23

M1 courses at Telecom Paris

• Peter Brown, Continuous Optimization and Numerical Analysis, ∼30 students, 24 hetd.

• Peter Brown and Romain Alléaume, Introduction to quantum information and quantum

computing, ∼25 students, 13.5 + 18 hetd.

M2 courses in the Quantum Engineering Program at Telecom Paris, (in collaboration with
ARTeQ, ENS Paris-Saclay)

• Romain Alléaume coordinates (2017-) the Quantum Engineering Program, a Access PhD Pro-
gram (M2 level) on Quantum Maths and TCS, and Quantum Technologies, that is currently
held in collaboration with ARTeQ (ENS Paris-Saclay) and M2 QDCS (Université Paris-Saclay).

• Peter Brown and Romain Alléaume, Quantum information tutorials, ∼10 students, M2 QEng,

6+6 hetd.

• Peter Brown and Romain Alléaume, Quantum information and quantum cryptography, M2

QEng Telecom Paris and ARTeQ, ∼30 students, 27+22.5 hetd.

• Cambyse Rouzé has started a new Quantum Computing course for the students of QEng

and ARTeQ.

– This course on the exploration of near-term quantum advantage delves into contem-
porary advancements in the theory of quantum computing and quantum information
processing. It covers a spectrum of topics, ranging from demonstrating quantum ad-
vantage in sampling tasks with a specific focus on BosonSampling experiments, to
exploring variational quantum algorithms tailored for solving constrained satisfaction
problems and their interplay with adiabatic quantum algorithms. Additionally, parti-
cipants were introduced to quantum state tomography, with the study of cutting-edge
shadow tomography algorithms.
– Taught 16 hetd, for ∼30 students

Teaching in other contexts and programs

• Romain Alléaume taught a short course on Quantum Cryptography Theory in the M1

Quantum Technologies atCentrale-Supélec 4,5 hetd, to ∼25 students.

• Peter Brown gave an Invited lecture at Padova QCOMMS summer school (May 2023) on

Device-independent quantum key distribution.

• Thomas Van Himbeeck gave an Invited lecture at Padova QCOMMS summer school (May

2023) on Finite-size effects in quantum key distribution.

10.2.2 Supervision

PhD Supervisions

• Tristan Nemoz, Computational models in quantum cryptography (Romain Alléaume and

Peter Brown), (2022-)

• Tristan Le Roy Deloison, Device-independent Quantum Key Distribution (Omar Fawzi

[QINFO] and Peter Brown), (2023-)

• Guillaume Ricard, Quantum Coherent Communications and Digital Signal Processing, (Ro-

main Alléaume and Yves Jaouën), (2021-)

• Francesco Mazzoncini, Communications quantiques multimodes et cryptographie hybride,

(Romain Alléaume and Sylvain Gigan [ENS Paris]), (2020-).

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Inria Annual Report 2023

• Pierre-Enguerrand Verdier, Cryptographie quantique à variables discrètes : caractérisation
de systèmes, déploiement opérationnel sur réseaux télécom et applications, (Thomas Rivera
[Orange] and Romain Alléaume), (2022-).

• Thomas Pousset, Protocoles de communications quantiques en variables temps-fréquence,

(Nicolas Fabre and Romain Alléaume), (2023-).

• Octave Mestoudjian, La notion de sous-système en informatique quantique, (Pablo Arrighi

(équipe Inria Quacs) and Augustin Vanrietvelde), (2023-).

• Jan Kochanowski, Analytic and algorithmic approaches on strong data processing in complex

quantum systems, (Omar Fawzi [QINFO] and Cambyse Rouzé), (2023-)

Master, PhD Track and L3 Students supervisions

• Rola Saidi, Evaluating crosstalk on quantum computers, QEng PRIM M2 project, (Peter Brown).

• Kriss Lady Stephanie Gutierrez Anco, Rényi intrinsic randomness, QEng PRIM M2 project,

(Peter Brown).

• Tristan Philippe, Ressource theory of quantum antecents to LWE, QEng PRIM M2 project,

(Romain Alléaume).

• Thomas Vinet, Distinguishing unitary gates using controlization, QEng PRIM M2 project,

(Augustin Vanrietvelde)

• Idris Delsol, Quantum error correction using Cat Qubits, QEng PRIM M2 project, (Cambyse

Rouzé)

• Ali Almasi, Positive but not completely positive maps, M1 PhD Track research project,

(Peter Brown)

• Timothé Bramas, Programming a LDPC-based Error Correction stack for CV-QKD, ENSTA

M1 research internship, (Romain Alléaume)

• Evdokia Gneusheva, Secret key-rates vs. entanglement, Polytechnique Bachelor L3 research

internship, (Peter Brown)

10.2.3 Juries

PhD juries

(Apart from our own students PhD juries)

• Romain Alléaume, Rapporteur for the PhD Defense of Yao Ma, Quantum Hardware Security

and Near-term Applications December 4 2023, Sorbonne University.

• Peter Brown, Examinator for the PhD Defense of Xavier Valcarce, Device independent
certification: quantum resources and quantum key distribution, Université Paris Saclay, May
17 2023.

10.3 Popularization

10.3.1 Articles and contents

• Romain Alléaume, Peter Brown, Cambyse Rouzé contributed to the writing of a wide

audience presentation article of Quriosity, for the Inria website.

• Romain Alléaume was interviewed by Isabelle Mauriac, for Telecom Paris Ideas, on the

scaling of quantum advantage, leading to short video and a podcast .

Project QURIOSITY

10.3.2 Interventions

25

• Romain Alléaume gave a talk "Nouvelles Quantiques de Télécom Paris", and participated to

an invited panel at the Prix des Technologlies Numériques, October 17, 2023.

• Romain Alléaume gave a presentation to a delegation from University of Hannover, on

Quantum Research activites at Quriosity, on March 12, 2023.

• Romain Alléaume gave an invited talk, on Quriosity, at Telecom Paris Journées Partenaires

Entreprises, on March 16, 2023;

• Romain Alléaume gave a talk on Quantum Computing to MEDEF Essonne, at ENS-Paris

Saclay, on October 20, 2023.

11 Scientific production

11.1 Major publications

[1] F. Mazzoncini, B. Bauer, P. Brown and R. Alléaume. Hybrid Quantum Cryptography from
Communication Complexity. 27th Nov. 2023. URL: https://telecom-paris.hal.scienc
e/hal-04328448.

[2] G. de Palma, M. Marvian, C. Rouzé and D. Stilck Franca. ‘Limitations of variational quantum
algorithms: a quantum optimal transport approach’. In: PRX Quantum 4 (23rd Jan. 2023),
p. 010309. DOI: 10.1103/PRXQuantum.4.010309. URL: https://hal.science/hal-
03675790.

[3] L. Wooltorton, P. Brown and R. Colbeck. Device-independent quantum key distribution with
arbitrarily small nonlocality. 18th Sept. 2023. URL: https://hal.science/hal-04267174.

11.2 Publications of the year

International journals

[4] L. Gao and C. Rouzé. ‘Coarse Ricci curvature of quantum channels’. In: Journal of Functional
Analysis (Jan. 2024), p. 110336. DOI: 10.1016/j.jfa.2024.110336. URL: https://hal
.science/hal-04406061.

[5] A. Henry, R. Raghunathan, G. Ricard, B. Lefaucher, F. Miatto, N. Belabas, I. Zaquine and
R. Alléaume. ‘Parallelizable Synthesis of Arbitrary Single-Qubit Gates with Linear Optics
and Time-Frequency Encoding’. In: Physical Review A 107.6 (June 2023), p. 062610. DOI:
10.1103/PhysRevA.107.062610. URL: https://hal.science/hal-03876857.

[6] C. Hirche, C. Rouzé and D. S. França. ‘Quantum Differential Privacy: An Information Theory
Perspective’. In: IEEE Transactions on Information Theory 69.9 (Sept. 2023), pp. 5771–5787. DOI:
10.1109/TIT.2023.3272904. URL: https://hal.science/hal-04386711.

[7] G. de Palma, M. Marvian, C. Rouzé and D. Stilck Franca. ‘Limitations of variational quantum
algorithms: a quantum optimal transport approach’. In: PRX Quantum 4 (23rd Jan. 2023),
p. 010309. DOI: 10.1103/PRXQuantum.4.010309. URL: https://hal.science/hal-
03675790.

Reports & preprints

[8] M. Caro, T. Gur, C. Rouzé, D. Stilck Franca and S. Subramanian. Information-theoretic general-
ization bounds for learning from quantum data. 9th Nov. 2023. URL: https://hal.science
/hal-04280232.

[9] M. Fanizza, N. Galke, J. Lumbreras, C. Rouzé and A. Winter. Learning finitely correlated states:
stability of the spectral reconstruction. 2023. URL: https://hal.science/hal-04410005.

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Inria Annual Report 2023

[10] R. Koenig and C. Rouzé. Limitations of local update recovery in stabilizer-GKP codes: a quantum
optimal transport approach. 2023. DOI: 10.48550/arXiv.2309.16241. URL: https://te
lecom-paris.hal.science/hal-04257028.

[11] F. Mazzoncini, B. Bauer, P. Brown and R. Alléaume. Hybrid Quantum Cryptography from
Communication Complexity. 27th Nov. 2023. URL: https://telecom-paris.hal.scienc
e/hal-04328448.

[12] E. Onorati, C. Rouzé, D. S. França and J. Watson. Provably Efficient Learning of Phases of Matter
via Dissipative Evolutions. 13th Nov. 2023. DOI: 10 . 48550 / arXiv . 2311 . 07506. URL:
https://hal.science/hal-04386728.

[13] C. Rouzé and D. S. França. Efficient learning of the structure and parameters of local Pauli noise
channels. 2023. DOI: 10.48550/arXiv.2307.02959. URL: https://hal.science/ha
l-04386732.

[14] A. Tavakoli, A. Pozas-Kerstjens, P. Brown and M. Araújo. Semidefinite programming relaxations

for quantum correlations. 2023. URL: https://hal.science/hal-04267171.

[15] L. Wooltorton, P. Brown and R. Colbeck. Device-independent quantum key distribution with
arbitrarily small nonlocality. 18th Sept. 2023. URL: https://hal.science/hal-04267174.
[16] L. Wooltorton, P. Brown and R. Colbeck. Expanding bipartite Bell inequalities for maximum
multi-partite randomness. 14th Aug. 2023. URL: https://hal.science/hal-04267172.

11.3 Cited publications

[17] S. Aaronson and A. Arkhipov. ‘The computational complexity of linear optics’. In: Proceedings

of the forty-third annual ACM symposium on Theory of computing. 2011, pp. 333–342.

[18] M. Araújo, F. Costa and ˙C. Brukner. ‘Computational advantage from quantum-controlled
ordering of gates’. In: Physical review letters 113.25 (2014), p. 250402. DOI: 10.1103/PhysRe
vLett.113.250402. arXiv: 1401.8127 [quant-ph].

[19] M. Araújo, A. Feix, F. Costa and ˙C. Brukner. ‘Quantum circuits cannot control unknown
operations’. In: New Journal of Physics 16.9 (2014), p. 093026. DOI: 10.1088/1367-2630/16
/9/093026. arXiv: 1309.7976 [quant-ph].

[20] R. Arnon-Friedman, F. Dupuis, O. Fawzi, R. Renner and T. Vidick. ‘Practical device-independent

quantum cryptography via entropy accumulation’. In: Nature communications 9.1 (2018),
p. 459.

[21] R. Aymeric, Y. Jaouën, C. Ware and R. Alléaume. ‘Symbiotic joint operation of quantum and

classical coherent communications’. In: arXiv preprint arXiv:2202.06942 (2022).

[22]

[23]

[24]

[25]

[26]

I. Bardet, Á. Capel, L. Gao, A. Lucia, D. Pérez-García and C. Rouzé. ‘Entropy decay for
Davies semigroups of a one dimensional quantum lattice’. In: arXiv preprint arXiv:2112.00601
(2021).

I. Bardet, Á. Capel, L. Gao, A. Lucia, D. Pérez-García and C. Rouzé. ‘Rapid thermalization of
spin chain commuting Hamiltonians’. In: arXiv preprint arXiv:2112.00593 (2021).

I. Bardet, Á. Capel and C. Rouzé. ‘Approximate Tensorization of the Relative Entropy for
Noncommuting Conditional Expectations’. In: Annales Henri Poincaré 23.1 (2021), pp. 101–
140.

I. Bardet, M. Junge, N. Laracuente, C. Rouzé and D. S. França. ‘Group Transference Tech-
niques for the Estimation of the Decoherence Times and Capacities of Quantum Markov
Semigroups’. In: IEEE Transactions on Information Theory 67.5 (2021), pp. 2878–2909. DOI:
10.1109/TIT.2021.3065452.
J. Barrett, R. Lorenz and O. Oreshkov. ‘Quantum causal models’. In: (). DOI: 10.48550/ar
Xiv.1906.10726. arXiv: 1906.10726 [quant-ph].

[27] S. Becker, N. Datta, L. Lami and C. Rouzé. ‘Classical shadow tomography for continuous

variables quantum systems’. In: arXiv preprint arXiv:2211.07578 (2022).

Project QURIOSITY

27

[28] P. Brown, H. Fawzi and O. Fawzi. ‘Computing conditional entropies for quantum correla-

tions’. In: Nature communications 12.1 (2021), pp. 1–12.

[29] P. Brown, H. Fawzi and O. Fawzi. ‘Device-independent lower bounds on the conditional

von Neumann entropy’. In: arXiv preprint arXiv:2106.13692 (2021).

[30] Y. Cai, J. Roslund, G. Ferrini, F. Arzani, X. Xu, C. Fabre and N. Treps. ‘Multimode entangle-
ment in reconfigurable graph states using optical frequency combs’. In: Nature communications
8.1 (2017), pp. 1–9.

[31] Á. Capel, C. Rouzé and D. S. França. ‘The modified logarithmic Sobolev inequality for
quantum spin systems: classical and commuting nearest neighbour interactions, (QIP talk,
presented at ICMP)’. In: arXiv:2009.11817 (2020).

[32] Z. Chen, K. Liu and E. Vigoda. ‘Optimal Mixing of Glauber Dynamics: Entropy Factorization
via High-Dimensional Expansion’. In: Proceedings of the 53rd Annual ACM SIGACT Symposium
on Theory of Computing. STOC 2021. Virtual, Italy: Association for Computing Machinery,
2021, 1537?1550. DOI: 10.1145/3406325.3451035. URL: https://doi.org/10.1145
/3406325.3451035.

[33] H.-C. Cheng, N. Datta and C. Rouzé. ‘Strong Converse Bounds in Quantum Network
Information Theory’. In: IEEE Transactions on Information Theory 67.4 (2021), pp. 2269–2292.
DOI: 10.1109/TIT.2021.3058166.

[34] G. Chiribella, G. M. D’Ariano, P. Perinotti and B. Valiron. ‘Quantum computations without
definite causal structure’. In: Physical Review A 88.2 (2013), p. 022318. DOI: 10.1103/Phys
RevA.88.022318. arXiv: 0912.0195 [quant-ph].

[35] F. Dupuis, O. Fawzi and R. Renner. ‘Entropy accumulation’. In: Communications in Mathemat-

ical Physics 379 (2020), pp. 1–47.

[36] P. Faist. ‘The Entropy Zoo’. In: https://phfaist.com/entropyzoo ().
[37] O. Faust and H. Fawzi. ‘Sum-of-Squares proofs of logarithmic Sobolev inequalities on finite

Markov chains’. In: arXiv preprint arXiv:2101.04988 (2021).

[38] L. Gao and C. Rouzé. ‘Complete Entropic Inequalities for Quantum Markov Chains’. In:
Archive for Rational Mechanics and Analysis 245.1 (May 2022), pp. 183–238. DOI: 10.1007/s0
0205-022-01785-1. URL: https://doi.org/10.1007%5C%2Fs00205-022-01785-
1.

[39] S. Guha, B. I. Erkmen and J. H. Shapiro. ‘The Entropy Photon-Number Inequality and its
consequences’. In: 2008 Information Theory and Applications Workshop. 2008, pp. 128–130. DOI:
10.1109/ITA.2008.4601037.

[40] T. A. Hahn and E. Y.-Z. Tan. ‘Fidelity Bounds for Device-Independent Advantage Distillation’.

In: arXiv preprint arXiv:2105.03213 (2021).

[41] H.-Y. Huang, R. Kueng and J. Preskill. ‘Predicting many properties of a quantum system from
very few measurements’. In: Nature Physics 16.10 (June 2020), pp. 1050–1057. DOI: 10.1038
/s41567-020-0932-7. URL: https://doi.org/10.1038/s41567-020-0932-7.

[42] H.-Y. Huang, R. Kueng, G. Torlai, V. V. Albert and J. Preskill. ‘Provably efficient machine
learning for quantum many-body problems’. In: arXiv preprint arXiv:2106.12627 (2021).

[43] K. Kazuro. ‘Fundamentals of Coherent Optical Fiber Communications’. In: in Journal of

Lightwave Technology vol. 34, N¬∞1 (2016).

[44] A. Kissinger and S. Uijlen. ‘A categorical semantics for causal structure’. In: Logical Methods
in Computer Science Volume 15, Issue 3 (2019). DOI: 10.23638/LMCS- 15(3:15)2019.
arXiv: 1701.04732 [quant-ph].

[45] S. Laplante, M. Laurière, A. Nolin, J. Roland and G. Senno. ‘Robust Bell inequalities from

communication complexity’. In: Quantum 2 (2018), p. 72.

[46] R. Lorenz and J. Barrett. ‘Causal and compositional structure of unitary transformations’.
In: Quantum 5 (2021), p. 511. DOI: 10.22331/q-2021-07-28-511. arXiv: 2001.07774
[quant-ph].

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[47] D. Nadlinger, P. Drmota, B. Nichol, G. Araneda, D. Main, R. Srinivas, D. Lucas, C. Ballance,
K. Ivanov, E. Tan et al. ‘Device-independent quantum key distribution’. In: arXiv preprint
arXiv:2109.14600 (2021).

[48] O. Regev and B. Klartag. ‘Quantum one-way communication can be exponentially stronger
than classical communication’. In: Proceedings of the forty-third annual ACM symposium on
Theory of computing. 2011, pp. 31–40.

[49] D. Rusca, T. Van Himbeeck, A. Martin, J. B. Brask, W. Shi, S. Pironio, N. Brunner and H.
Zbinden. ‘Self-testing quantum random-number generator based on an energy bound’. In:
Physical Review A 100.6 (2019), p. 062338.

[50] E. Y.-Z. Tan, R. Schwonnek, K. T. Goh, I. W. Primaatmaja and C. C.-W. Lim. ‘Computing secure
key rates for quantum cryptography with untrusted devices’. In: npj Quantum Information 7.1
(2021), pp. 1–6.

[51] E. Y.-Z. Tan, P. Sekatski, J.-D. Bancal, R. Schwonnek, R. Renner, N. Sangouard and C. C.-W.
Lim. ‘Improved DIQKD protocols with finite-size analysis’. In: arXiv preprint arXiv:2012.08714
(2020).

[52] A. Tavakoli. ‘Semi-device-independent framework based on restricted distrust in prepare-

and-measure experiments’. In: Physical Review Letters 126.21 (2021), p. 210503.

[53] A. Vanrietvelde, H. Kristjánsson and J. Barrett. ‘Routed quantum circuits’. In: Quantum 5 (July

2021), p. 503. DOI: 10.22331/q-2021-07-13-503. arXiv: 2011.08120 [quant-ph].

[54] A. Vanrietvelde, N. Ormrod, H. Kristjánsson and J. Barrett. ‘Consistent circuits for indefinite

causal order’. In: (June 2022). arXiv: 2206.10042 [quant-ph].

[55] C. J. Wood and R. W. Spekkens. ‘The lesson of causal discovery algorithms for quantum
correlations: causal explanations of Bell-inequality violations require fine-tuning’. In: New
Journal of Physics 17.3 (Mar. 2015), p. 033002. DOI: 10.1088/1367-2630/17/3/033002.
URL: http://dx.doi.org/10.1088/1367-2630/17/3/033002.

[56] W. Zhang, T. van Leent, K. Redeker, R. Garthoff, R. Schwonnek, F. Fertig, S. Eppelt, V.
Scarani, C. C.-W. Lim and H. Weinfurter. ‘Experimental device-independent quantum key
distribution between distant users’. In: arXiv preprint arXiv:2110.00575 (2021).

[57] Y. Zhang, H. Fu and E. Knill. ‘Efficient randomness certification by quantum probability

estimation’. In: Physical review research 2.1 (2020), p. 013016.
<scratchpad>
- Main topic: Research Centre (QURIOSITY) - Quantum Information Processing and Communication
- Key points:
  - QURIOSITY is a research centre focusing on quantum information processing and communication
  - The centre aims to extend the application horizon of quantum information science
  - Research areas include quantum cryptography, quantum communication, and quantum computing
  - The centre is in partnership with various institutions, including Institut Polytechnique de Paris and Inria
- Structure: The document appears to be a research centre's annual report, organized into sections on activity, theme, contents, application domains, social and environmental responsibility, highlights of the year, new results, bilateral contracts and grants, partnerships and cooperations, dissemination, and scientific production.
- Potential artifacts to ignore: web-related elements, such as links, HTML tags, and unnecessary formatting
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<final_summary>
QURIOSITY is a research centre that focuses on quantum information processing and communication, aiming to extend the application horizon of quantum information science. The centre is organized into three research axes: quantum cryptography complexity and hardware frontiers, multimode photonic systems for quantum information processing and communications, and mathematical foundations of quantum information. QURIOSITY is in partnership with various institutions and has received funding for bilateral contracts and grants, as well as partnerships and cooperations with European initiatives and national initiatives. The centre has made significant contributions to the field of quantum information science, including the development of new quantum cryptographic protocols and the study of multimode photonic systems for quantum information processing and communications. Overall, QURIOSITY is a leading research centre in the field of quantum information science, with a strong focus on advancing our understanding of quantum information processing and communication.
QURIOSITY is a research centre that focuses on quantum information processing and communication, aiming to extend the application horizon of quantum information science. The centre is organized into three research axes: quantum cryptography complexity and hardware frontiers, multimode photonic systems for quantum information processing and communications, and mathematical foundations of quantum information. QURIOSITY is in partnership with various institutions and has received funding for bilateral contracts and grants, as well as partnerships and cooperations with European initiatives and national initiatives. The centre has made significant contributions to the field of quantum information science, including the development of new quantum cryptographic protocols and the study of multimode photonic systems for quantum information processing and communications. Overall, QURIOSITY is a leading research centre in the field of quantum information science, with a strong focus on advancing our understanding of quantum information processing and communication.