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0704.0101
The birth of string theory
In this contribution we go through the developments that in the years 1968 to 1974 led from the Veneziano model to the bosonic string.
hep-th
0704.0102
Duality and Tameness
We prove a duality theorem for certain graded algebras and show by various examples different kinds of failure of tameness of local cohomology.
math.AC math.AG
0704.0103
Generalized regularly discontinuous solutions of the Einstein equations
The physical consistency of the match of piecewise-$C^0$ metrics is discussed. The mathematical theory of gravitational discontinuity hypersurfaces is generalized to cover the match of regularly discontinuous metrics. The mean-value differential geometry framework on a hypersurface is introduced, and corresponding co...
gr-qc
0704.0104
A geometric realization of sl(6,C)
Given an orientable weakly self-dual manifold X of rank two, we build a geometric realization of the Lie algebra sl(6,C) as a naturally defined algebra L of endomorphisms of the space of differential forms of X. We provide an explicit description of Serre generators in terms of natural generators of L. This construct...
math.DG math.RT
0704.0105
Rigid subsets of symplectic manifolds
We show that there is an hierarchy of intersection rigidity properties of sets in a closed symplectic manifold: some sets cannot be displaced by symplectomorphisms from more sets than the others. We also find new examples of rigidity of intersections involving, in particular, specific fibers of moment maps of Hamilto...
math.SG
0704.0106
Multiple Parton Scattering in Nuclei: Quark-quark Scattering
Modifications to quark and antiquark fragmentation functions due to quark-quark (antiquark) double scattering in nuclear medium are studied systematically up to order \cal{O}(\alpha_{s}^2)$ in deeply inelastic scattering (DIS) off nuclear targets. At the order $\cal{O}(\alpha_s^2)$, twist-four contributions from quar...
hep-ph nucl-th
0704.0107
Experimental modeling of physical laws
A physical law is represented by the probability distribution of a measured variable. The probability density is described by measured data using an estimator whose kernel is the instrument scattering function. The experimental information and data redundancy are defined in terms of information entropy. The model cos...
physics.data-an
0704.0108
Reducing SAT to 2-SAT
Description of a polynomial time reduction of SAT to 2-SAT of polynomial size.
cs.CC
0704.0109
Half-metallic silicon nanowires
From first-principles calculations, we predict that transition metal (TM) atom doped silicon nanowires have a half-metallic ground state. They are insulators for one spin-direction, but show metallic properties for the opposite spin direction. At high coverage of TM atoms, ferromagnetic silicon nanowires become metal...
cond-mat.mtrl-sci cond-mat.other
0704.0110
On Equivariant Embedding of Hilbert C^* modules
We prove that an arbitrary (not necessarily countably generated) Hilbert $G$-$\cla$ module on a G-C^* algebra $\cla$ admits an equivariant embedding into a trivial $G-\cla$ module, provided G is a compact Lie group and its action on $\cla$ is ergodic.
math.OA
0704.0111
Invariance and the twisted Chern character : a case study
We give details of the proof of the remark made in \cite{G2} that the Chern characters of the canonical generators on the K homology of the quantum group $SU_q(2)$ are not invariant under the natural $SU_q(2)$ coaction. Furthermore, the conjecture made in \cite{G2} about the nontriviality of the twisted Chern charact...
math.QA math.KT
0704.0112
Placeholder Substructures III: A Bit-String-Driven ''Recipe Theory'' for Infinite-Dimensional Zero-Divisor Spaces
Zero-divisors (ZDs) derived by Cayley-Dickson Process (CDP) from N-dimensional hypercomplex numbers (N a power of 2, at least 4) can represent singularities and, as N approaches infinite, fractals -- and thereby,scale-free networks. Any integer greater than 8 and not a power of 2 generates a meta-fractal or "Sky" whe...
math.RA
0704.0113
Langmuir blodgett assembly of densely aligned single walled carbon nanotubes from bulk materials
Single walled carbon nanotubes exhibit advanced electrical and surface properties useful for high performance nanoelectronics. Important to future manufacturing of nanotube circuits is large scale assembly of SWNTs into aligned forms. Despite progress in assembly and oriented synthesis, pristine SWNTs in aligned and ...
cond-mat.mtrl-sci
0704.0114
Quantum Phase Transition in the Four-Spin Exchange Antiferromagnet
We study the S=1/2 Heisenberg antiferromagnet on a square lattice with nearest-neighbor and plaquette four-spin exchanges (introduced by A.W. Sandvik, Phys. Rev. Lett. {\bf 98}, 227202 (2007).) This model undergoes a quantum phase transition from a spontaneously dimerized phase to N\'eel order at a critical couplin...
cond-mat.str-el
0704.0115
Smooth maps with singularities of bounded K-codimensions
We will prove the relative homotopy principle for smooth maps with singularities of a given {\cal K}-invariant class with a mild condition. We next study a filtration of the group of homotopy self-equivalences of a given manifold P by considering singularities of non-negative {\cal K}-codimensions.
math.GT
0704.0116
Stringy Jacobi fields in Morse theory
We consider the variation of the surface spanned by closed strings in a spacetime manifold. Using the Nambu-Goto string action, we induce the geodesic surface equation, the geodesic surface deviation equation which yields a Jacobi field, and we define the index form of a geodesic surface as in the case of point parti...
math-ph hep-th math.MP
0704.0117
Lower ground state due to counter-rotating wave interaction in trapped ion system
We consider a single ion confined in a trap under radiation of two traveling waves of lasers. In the strong-excitation regime and without the restriction of Lamb-Dicke limit, the Hamiltonian of the system is similar to a driving Jaynes-Cummings model without rotating wave approximation (RWA). The approach we develope...
quant-ph
0704.0118
Strained single-crystal Al2O3 grown layer-by-layer on Nb (110) thin films
We report on the layer-by-layer growth of single-crystal Al2O3 thin-films on Nb (110). Single-crystal Nb films are first prepared on A-plane sapphire, followed by the evaporation of Al in an O2 background. The first stages of Al2O3 growth are layer-by-layer with hexagonal symmetry. Electron and x-ray diffraction meas...
cond-mat.supr-con cond-mat.mtrl-sci
0704.0119
Quasi-quartet crystal electric field ground state in a tetragonal CeAg$_2$Ge$_2$ single crystal
We have successfully grown the single crystals of CeAg$_2$Ge$_2$, for the first time, by flux method and studied the anisotropic physical properties by measuring the electrical resistivity, magnetic susceptibility and specific heat. We found that CeAg$_2$Ge$_2$ undergoes an antiferromagnetic transition at $T_{\rm N}$...
cond-mat.str-el
0704.0120
Strong Phase and $D^0-D^0bar$ mixing at BES-III
Most recently, both BaBar and Belle experiments found evidences of neutral $D$ mixing. In this paper, we discuss the constraints on the strong phase difference in $D^0 \to K\pi$ decay from the measurements of the mixing parameters, $y^\prime$, $y_{CP}$ and $x$ at the $B$ factories. The sensitivity of the measurement ...
hep-ex hep-ph
0704.0121
Meta-Stable Brane Configuration of Product Gauge Groups
Starting from the N=1 SU(N_c) x SU(N_c') gauge theory with fundamental and bifundamental flavors, we apply the Seiberg dual to the first gauge group and obtain the N=1 dual gauge theory with dual matters including the gauge singlets. By analyzing the F-term equations of the superpotential, we describe the intersectin...
hep-th
0704.0122
Spinor dipolar Bose-Einstein condensates; Classical spin approach
Magnetic dipole-dipole interaction dominated Bose-Einstein condensates are discussed under spinful situations. We treat the spin degrees of freedom as a classical spin vector, approaching from large spin limit to obtain an effective minimal Hamiltonian; a version extended from a non-linear sigma model. By solving the...
cond-mat.other
0704.0123
Nonlinear Dynamics of the Phonon Stimulated Emission in Microwave Solid-State Resonator of the Nonautonomous Phaser Generator
The microwave phonon stimulated emission (SE) has been experimentally and numerically investigated in a nonautonomous microwave acoustic quantum generator, called also microwave phonon laser or phaser (see previous works arXiv:cond-mat/0303188 ; arXiv:cond-mat/0402640 ; arXiv:nlin.CG/0703050) Phenomena of branching a...
nlin.CD cond-mat.other physics.optics
0704.0124
Proper J-holomorphic discs in Stein domains of dimension 2
We prove the existence of global Bishop discs in a strictly pseudoconvex Stein domain in an almost complex manifold of complex dimension 2.
math.CV
0704.0125
Anisotropic thermo-elasticity in 2D -- Part I: A unified approach
In this note we develop tools and techniques for the treatment of anisotropic thermo-elasticity in two space dimensions. We use a diagonalisation technique to obtain properties of the characteristic roots of the full symbol of the system in order to prove $L^p$--$L^q$ decay rates for its solutions.
math.AP
0704.0126
I-V characteristics of the vortex state in MgB2 thin films
The current-voltage (I-V) characteristics of various MgB2 films have been studied at different magnetic fields parallel to c-axis. At fields \mu0H between 0 and 5T, vortex liquid-glass transitions were found in the I-V isotherms. Consistently, the I-V curves measured at different temperatures show a scaling behavior ...
cond-mat.supr-con
0704.0127
Magnetic Fingerprints of sub-100 nm Fe Nanodots
Sub-100 nm nanomagnets not only are technologically important, but also exhibit complex magnetization reversal behaviors as their dimensions are comparable to typical magnetic domain wall widths. Here we capture magnetic "fingerprints" of 1 billion Fe nanodots as they undergo a single domain to vortex state transitio...
cond-mat.mtrl-sci
0704.0128
An online repository of Swift/XRT light curves of GRBs
Context. Swift data are revolutionising our understanding of Gamma Ray Bursts. Since bursts fade rapidly, it is desirable to create and disseminate accurate light curves rapidly. Aims. To provide the community with an online repository of X-ray light curves obtained with Swift. The light curves should be of the qua...
astro-ph
0704.0129
On the total disconnectedness of the quotient Aubry set
In this paper we show that the quotient Aubry set associated to certain Lagrangians is totally disconnected (i.e., every connected component consists of a single point). Moreover, we discuss the relation between this problem and a Morse-Sard type property for (difference of) critical subsolutions of Hamilton-Jacobi e...
math.DS math-ph math.AP math.MP
0704.0130
New simple modular Lie superalgebras as generalized prolongs
Over algebraically closed fields of characteristic p>2, prolongations of the simple finite dimensional Lie algebras and Lie superalgebras with Cartan matrix are studied for certain simplest gradings of these algebras. Several new simple Lie superalgebras are discovered, serial and exceptional, including superBrown an...
math.RT
0704.0131
Vacuum Structure and Potential
Based on overall experimental observations, especially the pair processes, I developed a model structure of the vacuum along with a basic-particle formation scheme begun in 2000 (with collaborator P-I Johansson). The model consists in that the vacuum is, briefly, filled of neutral but polarizable vacuuons, consisting...
physics.gen-ph
0704.0132
Counterflow of electrons in two isolated quantum point contacts
We study the interaction between two adjacent but electrically isolated quantum point contacts (QPCs). At high enough source-drain bias on one QPC, the drive QPC, we detect a finite electric current in the second, unbiased, detector QPC. The current generated at the detector QPC always flows in the opposite direction...
cond-mat.mes-hall
0704.0133
PAH emission and star formation in the host of the z~2.56 Cloverleaf QSO
We report the first detection of the 6.2micron and 7.7micron infrared `PAH' emission features in the spectrum of a high redshift QSO, from the Spitzer-IRS spectrum of the Cloverleaf lensed QSO (H1413+117, z~2.56). The ratio of PAH features and rest frame far-infrared emission is the same as in lower luminosity star f...
astro-ph
0704.0134
Causal dissipative hydrodynamics for QGP fluid in 2+1 dimensions
In 2nd order causal dissipative theory, space-time evolution of QGP fluid is studied in 2+1 dimensions. Relaxation equations for shear stress tensors are solved simultaneously with the energy-momentum conservation equations. Comparison of evolution of ideal and viscous QGP fluid, initialized under the same conditions...
nucl-th
0704.0135
A Single Trapped Ion as a Time-Dependent Harmonic Oscillator
We show how a single trapped ion may be used to test a variety of important physical models realized as time-dependent harmonic oscillators. The ion itself functions as its own motional detector through laser-induced electronic transitions. Alsing et al. [Phys. Rev. Lett. 94, 220401 (2005)] proposed that an exponenti...
quant-ph
0704.0136
Compounding Fields and Their Quantum Equations in the Trigintaduonion Space
The 32-dimensional compounding fields and their quantum interplays in the trigintaduonion space can be presented by analogy with octonion and sedenion electromagnetic, gravitational, strong and weak interactions. In the trigintaduonion fields which are associated with the electromagnetic, gravitational, strong and we...
physics.gen-ph
0704.0137
Topological defects, geometric phases, and the angular momentum of light
Recent reports on the intriguing features of vector vortex bearing beams are analyzed using geometric phases in optics. It is argued that the spin redirection phase induced circular birefringence is the origin of topological phase singularities arising in the inhomogeneous polarization patterns. A unified picture of ...
quant-ph
0704.0138
Circular and non-circular nearly horizon-skimming orbits in Kerr spacetimes
We have performed a detailed analysis of orbital motion in the vicinity of a nearly extremal Kerr black hole. For very rapidly rotating black holes (spin a=J/M>0.9524M) we have found a class of very strong field eccentric orbits whose angular momentum L_z increases with the orbit's inclination with respect to the equ...
gr-qc astro-ph
0704.0139
The Blue Straggler Population of the Globular Cluster M5
By combining high-resolution HST and wide-field ground based observations, in ultraviolet and optical bands, we study the Blue Stragglers Star (BSS) population of the galactic globular cluster M5 (NGC 5904) from its very central regions up to its periphery. The BSS distribution is highly peaked in the cluster center,...
astro-ph
0704.0140
Entanglement entropy of two-dimensional Anti-de Sitter black holes
Using the AdS/CFT correspondence we derive a formula for the entanglement entropy of the anti-de Sitter black hole in two spacetime dimensions. The leading term in the large black hole mass expansion of our formula reproduces exactly the Bekenstein-Hawking entropy S_{BH}, whereas the subleading term behaves as ln S_{...
hep-th
0704.0141
Towards self-consistent definition of instanton liquid parameters
The possibility of self-consistent determination of instanton liquid parameters is discussed together with the definition of optimal pseudo-particle configurations and comparing the various pseudo-particle ensembles. The weakening of repulsive interactions between pseudo-particles is argued and estimated.
hep-ph
0704.0142
Some aspects of the nonperturbative renormalization of the phi^4 model
A nonperturbative renormalization of the phi^4 model is considered. First we integrate out only a single pair of conjugated modes with wave vectors +/- q. Then we are looking for the RG equation which would describe the transformation of the Hamiltonian under the integration over a shell Lambda - d Lambda < k < Lambd...
cond-mat.stat-mech
0704.0143
Instanton Liquid at Finite Temperature and Chemical Potential of Quarks
Instanton liquid in heated and strongly interacting matter is studied using the variational principle. The dependence of the instanton liquid density (gluon condensate) on the temperature and the quark chemical potential is determined under the assumption that, at finite temperatures, the dominant contribution is giv...
hep-ph
0704.0144
Eternal inflation and localization on the landscape
We model the essential features of eternal inflation on the landscape of a dense discretuum of vacua by the potential $V(\phi)=V_{0}+\delta V(\phi)$, where $|\delta V(\phi)|\ll V_{0}$ is random. We find that the diffusion of the distribution function $\rho(\phi,t)$ of the inflaton expectation value in different Hubbl...
hep-th astro-ph gr-qc
0704.0145
Singularity Resolution in Isotropic Loop Quantum Cosmology: Recent Developments
Since the past Iagrg meeting in December 2004, new developments in loop quantum cosmology have taken place, especially with regards to the resolution of the Big Bang singularity in the isotropic models. The singularity resolution issue has been discussed in terms of physical quantities (expectation values of Dirac ob...
gr-qc
0704.0146
Vortices in Bose-Einstein Condensates: Theory
Vortices are pervasive in nature, representing the breakdown of laminar fluid flow and hence playing a key role in turbulence. The fluid rotation associated with a vortex can be parameterized by the circulation $\Gamma=\oint {\rm d}{\bf r}\cdot{\bf v}({\bf r})$ about the vortex, where ${\bf v}({\bf r})$ is the fluid ...
cond-mat.other
0704.0147
A POVM view of the ensemble approach to polarization optics
Statistical ensemble formalism of Kim, Mandel and Wolf (J. Opt. Soc. Am. A 4, 433 (1987)) offers a realistic model for characterizing the effect of stochastic non-image forming optical media on the state of polarization of transmittedlight. With suitable choice of the Jones ensemble, various Mueller transformations -...
physics.optics physics.class-ph quant-ph
0704.0148
Reexamination of spin decoherence in semiconductor quantum dots from equation-of-motion approach
The longitudinal and transversal spin decoherence times, $T_1$ and $T_2$, in semiconductor quantum dots are investigated from equation-of-motion approach for different magnetic fields, quantum dot sizes, and temperatures. Various mechanisms, such as the hyperfine interaction with the surrounding nuclei, the Dresselha...
cond-mat.mtrl-sci
0704.0149
Construction of initial data for 3+1 numerical relativity
This lecture is devoted to the problem of computing initial data for the Cauchy problem of 3+1 general relativity. The main task is to solve the constraint equations. The conformal technique, introduced by Lichnerowicz and enhanced by York, is presented. Two standard methods, the conformal transverse-traceless one an...
gr-qc
0704.0150
Magnetism and Thermodynamics of Spin-1/2 Heisenberg Diamond Chains in a Magnetic Field
The magnetic and thermodynamic properties of spin-1/2 Heisenberg diamond chains are investigated in three different cases: (a) J1, J2, J3>0 (frustrated); (b) J1, J3<0, J2>0 (frustrated); and (c) J1, J2>0, J3<0 (non-frustrated). The density matrix renormalization group (DMRG) technique is invoked to study the properti...
cond-mat.str-el
0704.0151
Extraction of physical laws from joint experimental data
The extraction of a physical law y=yo(x) from joint experimental data about x and y is treated. The joint, the marginal and the conditional probability density functions (PDF) are expressed by given data over an estimator whose kernel is the instrument scattering function. As an optimal estimator of yo(x) the conditi...
physics.data-an physics.comp-ph
0704.0152
Kinetic equation for finite systems of fermions with pairing
The solutions of the Wigner-transformed time-dependent Hartree--Fock--Bogoliubov equations are studied in the constant-$\Delta$ approximation. This approximation is known to violate particle-number conservation. As a consequence, the density fluctuation and the longitudinal response function given by this approximati...
nucl-th
0704.0153
Reciprocal Symmetry and Classical Discrete Oscillator Incorporating Half-Integral Energy Levels
Classical oscillator differential equation is replaced by the corresponding (finite time) difference equation. The equation is, then, symmetrized so that it remains invariant under the change d going to -d, where d is the smallest span of time. This symmetric equation has solutions, which come in reciprocally related...
physics.gen-ph
0704.0154
Hadrons in Medium -- Theory confronts experiment
In this talk we briefly summarize our theoretical understanding of in-medium selfenergies of hadrons. With the special case of the $\omega$ meson we demonstrate that earlier calculations that predicted a significant lowering of the mass in medium are based on an incorrect treatment of the model Lagrangian; more consi...
nucl-th hep-ph nucl-ex
0704.0155
A computer program for fast non-LTE analysis of interstellar line spectra
The large quantity and high quality of modern radio and infrared line observations require efficient modeling techniques to infer physical and chemical parameters such as temperature, density, and molecular abundances. We present a computer program to calculate the intensities of atomic and molecular lines produced i...
astro-ph
0704.0156
Nonlinear force-free coronal magnetic field extrapolation scheme based on the direct boundary integral formulation
This paper has been withdrawn by the authors.
astro-ph
0704.0157
Alternative Approaches to the Equilibrium Properties of Hard-Sphere Liquids
An overview of some analytical approaches to the computation of the structural and thermodynamic properties of single component and multicomponent hard-sphere fluids is provided. For the structural properties, they yield a thermodynamically consistent formulation, thus improving and extending the known analytical res...
cond-mat.stat-mech cond-mat.soft physics.chem-ph
0704.0158
Complexities of Human Promoter Sequences
By means of the diffusion entropy approach, we detect the scale-invariance characteristics embedded in the 4737 human promoter sequences. The exponent for the scale-invariance is in a wide range of $[ {0.3,0.9} ]$, which centered at $\delta_c = 0.66$. The distribution of the exponent can be separated into left and ri...
q-bio.OT
0704.0159
Evidence for an excitonic insulator phase in 1T-TiSe$_{2}$
We present a new high-resolution angle-resolved photoemission study of 1\textit{T}-TiSe$_{2}$ in both, its room-temperature, normal phase and its low-temperature, charge-density wave phase. At low temperature the photoemission spectra are strongly modified, with large band renormalisations at high-symmetry points of ...
cond-mat.str-el cond-mat.soft
0704.0160
Oxygen-rich droplets and the enrichment of the ISM
We argue that the discrepancies observed in HII regions between abundances derived from optical recombination lines (ORLs) and collisionally excited lines (CELs) might well be the signature of a scenario of the enrichment of the interstellar medium (ISM) proposed by Tenorio-Tagle (1996). In this scenario, the fresh o...
astro-ph
0704.0161
Soft modes and NTE in Zn(CN)2 from Raman spectroscopy and first principles calculations
We have studied Zn(CN)2 at high pressure using Raman spectroscopy, and report Gruneisen parameters of the soft phonons. The phonon frequencies and eigen vectors obtained from ab-initio calculations are used for the assignment of the observed phonon spectra. Out of the eleven zone-centre optical modes, six modes exhib...
cond-mat.mtrl-sci
0704.0162
Estimation of experimental data redundancy and related statistics
Redundancy of experimental data is the basic statistic from which the complexity of a natural phenomenon and the proper number of experiments needed for its exploration can be estimated. The redundancy is expressed by the entropy of information pertaining to the probability density function of experimental variables....
physics.data-an physics.comp-ph
0704.0163
Effective potentials for quasicrystals from ab-initio data
Classical effective potentials are indispensable for any large-scale atomistic simulations, and the relevance of simulation results crucially depends on the quality of the potentials used. For complex alloys like quasicrystals, however, realistic effective potentials are practically inexistent. We report here on our ...
cond-mat.mtrl-sci
0704.0164
On smooth foliations with Morse singularities
Let $M$ be a smooth manifold and let $\F$ be a codimension one, $C^\infty$ foliation on $M$, with isolated singularities of Morse type. The study and classification of pairs $(M,\F)$ is a challenging (and difficult) problem. In this setting, a classical result due to Reeb \cite{Reeb} states that a manifold admitting ...
math.GT
0704.0165
Frobenius-Schur indicators for semisimple Lie algebras
Let g be a finite dimensional complex semisimple Lie algebra, and let V be a finite dimensional represenation of g. We give a closed formula for the mth Frobenius-Schur indicator, m>1, of V in representation-theoretic terms. We deduce that the indicators take integer values, and that for a large enough m, the mth ind...
math.QA math.RT
0704.0166
Supersymmetry breaking metastable vacua in runaway quiver gauge theories
In this paper we consider quiver gauge theories with fractional branes whose infrared dynamics removes the classical supersymmetric vacua (DSB branes). We show that addition of flavors to these theories (via additional non-compact branes) leads to local meta-stable supersymmetry breaking minima, closely related to th...
hep-th
0704.0167
Low Energy Aspects of Heavy Meson Decays
I discuss low energy aspects of heavy meson decays, where there is at least one heavy meson in the final state. Examples are $B -\bar{B}$ mixing, $B \to D \bar{D}$, $B \to D \eta'$, and $B \to D \gamma$. %and $B \to D W $ (Isgur-Wise function). The analysis is performed in the heavy quark limit within heavy-light chi...
hep-ph
0704.0168
Radiative losses and cut-offs of energetic particles at relativistic shocks
We investigate the acceleration and simultaneous radiative losses of electrons in the vicinity of relativistic shocks. Particles undergo pitch angle diffusion, gaining energy as they cross the shock by the Fermi mechanism and also emitting synchrotron radiation in the ambient magnetic field. A semi-analytic approach ...
astro-ph
0704.0169
Very strong and slowly varying magnetic fields as source of axions
The investigation on the production of particles in slowly varying but extremely intense magnetic field in extended to the case of axions. The motivation is, as for some previously considered cases, the possibility that such kind of magnetic field may exist around very compact astrophysical objects.
hep-ph
0704.0170
Symmetry disquisition on the TiOX phase diagram
The sequence of phase transitions and the symmetry of in particular the low temperature incommensurate and spin-Peierls phases of the quasi one-dimensional inorganic spin-Peierls system TiOX (TiOBr and TiOCl) have been studied using inelastic light scattering experiments. The anomalous first-order character of the tr...
cond-mat.str-el cond-mat.mtrl-sci
0704.0171
Discovery of a point-like very-high-energy gamma-ray source in Monoceros
The complex Monoceros Loop SNR/Rosette Nebula region contains several potential sources of very-high-energy (VHE) gamma-ray emission and two as yet unidentified high-energy EGRET sources. Sensitive VHE observations are required to probe acceleration processes in this region. The H.E.S.S. telescope array has been used...
astro-ph
0704.0172
Thermal entanglement of qubit pairs on the Shastry-Sutherland lattice
We show that temperature and magnetic field properties of the entanglement between spins on the two-dimensional Shastry-Sutherland lattice can be qualitatively described by analytical results for a qubit tetramer. Exact diagonalization of clusters with up to 20 sites reveals that the regime of fully entangled neighbo...
cond-mat.mes-hall cond-mat.str-el
0704.0173
Bonding of H in O vacancies of ZnO
We investigate the bonding of H in O vacancies of ZnO using density functional calculations. We find that H is anionic and does not form multicenter bonds with Zn in this compound.
cond-mat.mtrl-sci
0704.0174
Reparametrization Invariance, the controversial extraction of $\alpha$ from $B\to\pi\pi$ and New Physics
The extraction of the weak phase $\alpha$ from $B\to\pi\pi$ decays has been controversial from a statistical point of view, as the frequentist vs. bayesian confrontation shows. We analyse several relevant questions which have not deserved full attention and pervade the extraction of $\alpha$. Reparametrization Invari...
hep-ph hep-ex
0704.0175
Solar System Constraints on Gauss-Bonnet Mediated Dark Energy
Although the Gauss-Bonnet term is a topological invariant for general relativity, it couples naturally to a quintessence scalar field, modifying gravity at solar system scales. We determine the solar system constraints due to this term by evaluating the post-Newtonian metric for a distributional source. We find a mas...
astro-ph gr-qc hep-th
0704.0176
Switching mechanism of photochromic diarylethene derivatives molecular junctions
The electronic transport properties and switching mechanism of single photochromic diarylethene derivatives sandwiched between two gold surfaces with closed and open configurations are investigated by a fully self-consistent nonequilibrium Green's function method combined with density functional theory. The calculate...
cond-mat.other cond-mat.mtrl-sci
0704.0177
Robust manipulation of electron spin coherence in an ensemble of singly charged quantum dots
Using the recently reported mode locking effect we demonstrate a highly robust control of electron spin coherence in an ensemble of (In,Ga)As quantum dots during the single spin coherence time. The spin precession in a transverse magnetic field can be fully controlled up to 25 K by the parameters of the exciting puls...
physics.optics
0704.0178
Equation of state for dense hydrogen and plasma phase transition
We calculate the equation of state of dense hydrogen within the chemical picture. Fluid variational theory is generalized for a multi-component system of molecules, atoms, electrons, and protons. Chemical equilibrium is supposed for the reactions dissociation and ionization. We identify the region of thermodynamic in...
physics.plasm-ph
0704.0179
Experimental nonclassicality of single-photon-added thermal light states
We report the experimental realization and tomographic analysis of novel quantum light states obtained by exciting a classical thermal field by a single photon. Such states, although completely incoherent, possess a tunable degree of quantumness which is here exploited to put to a stringent experimental test some of ...
quant-ph
0704.0180
Neutron Skin and Giant Resonances in Nuclei
Some aspects, both experimental and theoretical, of extracting the neutron skin $\Delta R$ from properties of isovector giant resonances are discussed. Existing proposals are critically reviewed. The method relying on the energy difference between the GTR and IAS is shown to lack sensitivity to $\Delta R$. A simple e...
nucl-th
0704.0181
Genetic Optimization of Photonic Bandgap Structures
We investigate the use of a Genetic Algorithm (GA) to design a set of photonic crystals (PCs) in one and two dimensions. Our flexible design methodology allows us to optimize PC structures which are optimized for specific objectives. In this paper, we report the results of several such GA-based PC optimizations. We s...
physics.optics physics.comp-ph
0704.0182
Huge magneto-crystalline anisotropy of x-ray linear dichroism observed on Co/FeMn bilayers
We present an x-ray spectromicroscopic investigation of single-crystalline magnetic FeMn/Co bilayers on Cu(001), using X-ray magnetic circular (XMCD) and linear (XMLD) dichroism at the Co and Fe L3 absorption edges in combination with photoelectron emission microscopy (PEEM). Using the magnetic coupling between the f...
cond-mat.mtrl-sci
0704.0183
Temperature Dependence of the Tensile Properties of Single Walled Carbon Nanotubes: O(N) Tight Binding MD Simulation
This paper examines the effect of temperature on the structural stability and mechanical properties of 20 layered (10,10) single walled carbon nanotubes (SWCNTs) under tensile loading using an O(N) tight binding molecular dynamics (TBMD) simulation method. We observed that (10,10) tube can sustain its structural stab...
cond-mat.mtrl-sci
0704.0184
Gamma-ray emitting AGN and GLAST
I describe the different classes of Active Galactic Nuclei (AGN) and the basic tenets of unified schemes. I then review the properties of the extragalactic sources detected in the GeV and TeV bands, showing that the vast majority of them belong to the very rare blazar class. I further discuss the kind of AGN GLAST is...
astro-ph
0704.0185
Potfit: effective potentials from ab-initio data
We present a program called potfit which generates an effective atomic interaction potential by matching it to a set of reference data computed in first-principles calculations. It thus allows to perform large-scale atomistic simulations of materials with physically justified potentials. We describe the fundamental p...
cond-mat.mtrl-sci
0704.0186
Dark energy and neutrino model in SUSY -- Remarks on active and sterile neutrinos mixing --
We consider a Mass Varying Neutrinos (MaVaNs) model in supersymmetric theory. The model includes effects of supersymmetry breaking transmitted by the gravitational interaction from the hidden sector, in which supersymmetry was broken, to the dark energy sector. Then evolutions of the neutrino mass and the equation of...
hep-ph
0704.0187
The transverse proximity effect in spectral hardness on the line of sight towards HE 2347-4342
We report the discovery of 14 quasars in the vicinity of HE2347-4342, one of the two quasars whose intergalactic HeII forest has been resolved with FUSE. By analysing the HI and the HeII opacity variations separately, no transverse proximity effect is detected near three foreground quasars of HE2347-4342: QSOJ23503-4...
astro-ph
0704.0188
Biased random walks on combs
We develop rigorous, analytic techniques to study the behaviour of biased random walks on combs. This enables us to calculate exactly the spectral dimension of random comb ensembles for any bias scenario in the teeth or spine. Two specific examples of random comb ensembles are discussed; the random comb with nonzero ...
cond-mat.other
0704.0189
Monoid generalizations of the Richard Thompson groups
The groups G_{k,1} of Richard Thompson and Graham Higman can be generalized in a natural way to monoids, that we call M_{k,1}, and to inverse monoids, called Inv_{k,1}; this is done by simply generalizing bijections to partial functions or partial injective functions. The monoids M_{k,1} have connections with circuit...
math.GR
0704.0190
The Reliability on the Direction of the Incident Neutrino for the Fully Contained Events and Partially Contained Events due to QEL in the Super-Kamiokande
In the SK analysis of the neutrino events for [Fully Contained Events] and [Partially Contained Events] on their zenith angle distribution, it is assumed that the zenith angle of the incident neutrino is the same as that of the detected charged lepton. In the present paper, we examine the validity of [the SK assumpti...
hep-ex astro-ph hep-ph
0704.0191
Intricate Knots in Proteins: Function and Evolution
A number of recently discovered protein structures incorporate a rather unexpected structural feature: a knot in the polypeptide backbone. These knots are extremely rare, but their occurrence is likely connected to protein function in as yet unexplored fashion. Our analysis of the complete Protein Data Bank reveals s...
physics.bio-ph physics.data-an q-bio.BM
0704.0192
Star Formation in Galaxies with Large Lower Surface Brightness Disks
We present B, R, and Halpha imaging data of 19 large disk galaxies whose properties are intermediate between classical low surface brightness galaxies and ordinary high surface brightness galaxies. We use data taken from the Lowell 1.8m Perkins telescope to determine the galaxies' overall morphology, color, and star ...
astro-ph
0704.0193
Domain Wall Dynamics near a Quantum Critical Point
We study the real-time domain-wall dynamics near a quantum critical point of the one-dimensional anisotropic ferromagnetic spin 1/2 chain. By numerical simulation, we find the domain wall is dynamically stable in the Heisenberg-Ising model. Near the quantum critical point, the width of the domain wall diverges as $(\...
cond-mat.mtrl-sci cond-mat.stat-mech
0704.0194
Quantum mechanical approach to decoherence and relaxation generated by fluctuating environment
We consider an electrostatic qubit, interacting with a fluctuating charge of single electron transistor (SET) in the framework of exactly solvable model. The SET plays a role of the fluctuating environment affecting the qubit's parameters in a controllable way. We derive the rate equations describing dynamics of the ...
cond-mat.mes-hall quant-ph
0704.0195
Group-theoretical properties of nilpotent modular categories
We characterize a natural class of modular categories of prime power Frobenius-Perron dimension as representation categories of twisted doubles of finite p-groups. We also show that a nilpotent braided fusion category C admits an analogue of the Sylow decomposition. If the simple objects of C have integral Frobenius-...
math.QA math.RT
0704.0196
Remarks on N_c dependence of decays of exotic baryons
We calculate the N_c dependence of the decay widths of exotic eikosiheptaplet within the framework of Chral Quark Soliton Model. We also discuss generalizations of regular baryon representations for arbitrary N_c.
hep-ph
0704.0197
Analysis of random Boolean networks using the average sensitivity
In this work we consider random Boolean networks that provide a general model for genetic regulatory networks. We extend the analysis of James Lynch who was able to proof Kauffman's conjecture that in the ordered phase of random networks, the number of ineffective and freezing gates is large, where as in the disorder...
nlin.CG
0704.0198
Theory of polariton mediated Raman scattering in microcavities
We calculate the intensity of the polariton mediated inelastic light scattering in semiconductor microcavities. We treat the exciton-photon coupling nonperturbatively and incorporate lifetime effects in both excitons and photons, and a coupling of the photons to the electron-hole continuum. Taking the matrix elements...
cond-mat.str-el cond-mat.other
0704.0199
Decomposition numbers for finite Coxeter groups and generalised non-crossing partitions
Given a finite irreducible Coxeter group $W$, a positive integer $d$, and types $T_1,T_2,...,T_d$ (in the sense of the classification of finite Coxeter groups), we compute the number of decompositions $c=\si_1\si_2 cdots\si_d$ of a Coxeter element $c$ of $W$, such that $\si_i$ is a Coxeter element in a subgroup of ty...
math.CO math.GR
0704.0200
Electromagnetic polarizabilities and the excited states of the nucleon
The electromagnetic polarizabilities of the nucleon are shown to be essentially composed of the nonresonant $\alpha_p(E_{0+})=+3.2$, $\alpha_n(E_{0+})=+4.1$,the $t$-channel $\alpha^t_{p,n}=-\beta^t_{p,n}=+7.6$ and the resonant $\beta_{p,n}(P_{33}(1232))=+8.3$ contributions (in units of $10^{-4}$fm$^3$. The remaining ...
hep-ph nucl-ex