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2008-02-08
Large deviations of lattice Hamiltonian dynamics coupled to stochastic thermostats
We discuss the Donsker-Varadhan theory of large deviations in the framework of Hamiltonian systems thermostated by a Gaussian stochastic coupling. We derive a general formula for the Donsker-Varadhan large deviation functional for dynamics which satisfy natural properties under time reversal. Next, we discuss the chara...
0802.1104v2
2008-02-12
Coherence Conservation of a Qubit Coupled to a Thermal Dissipating Environment
It is shown that quantum coherence is conserved in a principal system in the case that the system is coupled to a fast dissipating environment [arXiv:0709.0562]. The phenomenon is called the quantum wipe effect. Here, this effect is reviewed and the analytical proof for a model system consisting of a one-qubit system c...
0802.1596v1
2008-02-13
The supersymmetric solutions and extensions of ungauged matter-coupled N=1,d=4 supergravity
We find the most general supersymmetric solutions of ungauged N=1,d=4 supergravity coupled to an arbitrary number of vector and chiral supermultiplets, which turn out to be essentially pp-waves and strings. We also introduce magnetic 1-forms and their supersymmetry transformations and 2-forms associated to the isometri...
0802.1799v2
2008-02-18
Spin-orbit coupling and crystal-field splitting in the electronic and optical properties of nitride quantum dots with a wurtzite crystal structure
We present an $sp^3$ tight-binding model for the calculation of the electronic and optical properties of wurtzite semiconductor quantum dots (QDs). The tight-binding model takes into account strain, piezoelectricity, spin-orbit coupling and crystal-field splitting. Excitonic absorption spectra are calculated using the ...
0802.2436v1
2008-02-20
Theoretical and experimental investigations of Coulomb blockade in coupled quantum dot systems
Two strongly coupled quantum dots are theoretically and experimentally investigated. In the conductance measurements of a GaAs based low-dimensional system additional features to the Coulomb blockade have been detected at low temperatures. These regions of finite conductivity are compared with theoretical investigation...
0802.2799v1
2008-02-26
Decoherence by a spin thermal bath: Role of the spin-spin interactions and initial state of the bath
We study the decoherence of two coupled spins that interact with a spin-bath environment. It is shown that the connectivity and the coupling strength between the spins in the environment are of crucial importance for the decoherence of the central system. For the anisotropic spin-bath, changing the connectivity or coup...
0802.3828v1
2008-03-06
Quantum information processing in a spin-bus system of coupled chains
The effective Heisenberg interaction of long distance is constructed in spin qubits connected to a bus of two strongly coupled chains. Universal quantum computation can be realized on the basis of the bus which always keeps frozen at the ground state. It is found that the effective interaction is primarily determined b...
0803.0768v1
2008-03-07
Strong electron-phonon interaction in multiband superconductors
We discuss the effects of anisotropy on superconducting critical temperature and order parameter in a strongly coupled regime. The multiband representation is used as a model for anisotropy. We show that strong coupling effects in multiband superconductors lead to pair-breaking due to interband coupling because soft ph...
0803.1103v1
2008-03-10
Four point function of R-currents in N=4 SYM in the Regge limit at weak coupling
We compute, in N=4 super Yang-Mills theory, the four point correlation function of R-currents in the Regge limit in the leading logarithmic approximation at weak coupling. Such a correlator is the closest analog to photon-photon scattering within QCD, and there is a well-defined procedure to perform the analogous compu...
0803.1423v2
2008-03-11
Gauge and Yukawa couplings in 6D supersymmetric SU(6) models
We study six-dimensional (6D) SU(6) supersymmetric models where the doublet-triplet splitting, quark-lepton mass relations and gaugino-mediated supersymmetry breaking are taken into account. We find that effective 4D gauge coupling constants have highly nontrivial behavior between two compactification scales. It is sho...
0803.1537v1
2008-03-13
Resonances for a Hydrogenic System or a Harmonic Oscillator Strongly Coupled to a Field
We calculate resonances which are formed by a particle in a potential which is either Coulombian or quadratic when the particle is strongly coupled to a massless boson, taking only two energy levels into consideration. From these calculations we derive how the moving away of the particle from its attraction center goes...
0803.1973v1
2008-03-14
An alternative scaling solution for high-energy QCD saturation with running coupling
A new type of approximate scaling compatible with the Balitsky-Kovchegov equation with running coupling is found, which is different from the previously known running coupling geometric scaling. The corresponding asymptotic traveling wave solution is derived. Although featuring different scaling behaviors, the two solu...
0803.2167v1
2008-03-18
Superconductivity in a model of two Hubbard chains coupled with ferromagnetic exchange interaction
We study the ground-state properties of the double-chain Hubbard model coupled with ferromagnetic exchange interaction by using the weak-coupling theory, density-matrix renormalization group technique, and Lanczos exact-diagonalization method. We determine the ground-state phase diagram in the parameter space of the fe...
0803.2590v1
2008-03-18
Efficient output coupling of intracavity high harmonic generation
We demonstrate a novel technique for coupling XUV harmonic radiation out of a femtosecond enhancement cavity. We use a small-period diffraction grating etched directly into the surface of a dielectric mirror. For the fundamental light, this element acts as a high reflector. For harmonic wavelengths, it acts as a diffra...
0803.2672v1
2008-03-19
On Matter Coupling in 5D Kaluza-Klein Model
We analyze some unphysical features of the geodesic approach to matter coupling in a compactified Kaluza-Klein scenario, like the q/m puzzle and the huge massive modes. We propose a new approach, based on Papapetrou multipole expansion, that provides a new equation for the motion of a test particle. We show how this eq...
0803.2807v1
2008-03-20
Short chaotic strings and their behaviour in the scaling region
Coupled map lattices are a paradigm of higher-dimensional dynamical systems exhibiting spatio-temporal chaos. A special case of non-hyperbolic maps are one-dimensional map lattices of coupled Chebyshev maps with periodic boundary conditions, called chaotic strings. In this short note we show that the fine structure of ...
0803.2991v2
2008-03-20
Non-minimally coupled vector curvaton
It is shown that a massive Abelian vector boson field can generate the curvature perturbation in the Universe, when coupled non-minimally to gravity, through an RA^2 coupling. The vector boson acts as a curvaton field imposing the curvature perturbation after the end of inflation, without generating a large-scale aniso...
0803.3041v2
2008-03-20
A Lindblad model for a spin chain coupled to heat baths
We study a XY model which consists of a spin chain coupled to heat baths. We give a repeated quantum interaction Hamiltonian describing this model. We compute the explicit form of the associated Lindblad generator in the case of the spin chain coupled to one, two and several heat baths. We further study the properties ...
0803.3060v1
2008-03-25
Universality in Globally Coupled Maps and Flows
We show that universality in chaotic elements can be lifted to that in complex systems. We construct a globally coupled Flow lattice (GCFL), an analog of a globally coupled Map lattice (GCML). We find that Duffing GCFL shows the same behavior with GCML; population ratio between synchronizing clusters acts as a bifurcat...
0803.3589v1
2008-03-28
Kondo-Dicke resonances in electronic transport through triple quantum dots
Electronic transport through a triple quantum dot system, with only a single dot coupled directly to external leads, is considered theoretically. The model includes Coulomb correlations in the central dot, while such correlations in the two side-coupled dots are omitted. The infinite-U mean-field slave-boson approach i...
0803.4154v1
2008-03-31
Quark-meson coupling model with the cloudy bag
Using the volume coupling version of the cloudy bag model, the quark-meson coupling model is extended to study the role of pion field and the properties of nuclear matter. The extended model includes the effect of gluon exchange as well as the pion-cloud effect, and provides a good description of the nuclear matter pro...
0803.4362v1
2008-04-01
Strong electron-phonon coupling of the Fe breathing mode of LaO_{1-x}F_xFeAs
The electron-phonon coupling of LaO$_{1-x}$F$_x$FeAs is re-investigated on the basis of density functional theory in local density approximation. The implications of the $(\pi,\pi)$ nesting of the Fermi surfaces are carefully studied and found to lead to a non-standard electron-phonon coupling of the corresponding Fe i...
0804.0186v2
2008-04-02
A strong coupling expansion for N=4 SYM theory and other SCFT's
Recent progress towards understanding a strong coupling expansion for various superconformal field theories in four dimensions is described. First, the case of the maximally supersymmetric Yang Mills theory is analyzed, as well as many calculations that can be done directly at strong coupling and matched to the AdS dua...
0804.0383v1
2008-04-11
Running Coupling Effects in Small-x QCD
We study effects of the running of the coupling in QCD at small Bjorken-x and in particular the ones related to gluon saturation. After introducing the steps taken to the derivation of the next to leading order nonlinear evolution equation, we discuss the infrared sensitivity of the Pomeron intercept, the energy depend...
0804.1918v1
2008-04-15
Interface-driven magnetocapacitance in a broad range of materials
Triggered by the revival of multiferroic materials, a lot of effort is presently undergoing as to find a coupling between a capacitance and a magnetic field. We show in this report that interfaces are the right way of increasing such a coupling provided free charges are localized on these two-dimensional defects. Start...
0804.2416v1
2008-04-22
A triple quantum dot in a single wall carbon nanotube
A top-gated single wall carbon nanotube is used to define three coupled quantum dots in series between two electrodes. The additional electron number on each quantum dot is controlled by top-gate voltages allowing for current measurements of single, double and triple quantum dot stability diagrams. Simulations using a ...
0804.3441v1
2008-04-30
Quantum dynamics in nonequilibrium environments
We present a formalism for studying the behaviour of quantum systems coupled to nonequilibrium environments exhibiting nonGaussian fluctuations. We discuss the role of a qubit as a detector of the statistics of environmental fluctuations, as well as nonMarkovian effects in both weak and strong coupling limits. We also ...
0804.4869v2
2008-05-05
Inferring coupling strength from event-related dynamics
We propose an approach for inferring strength of coupling between two systems from their transient dynamics. This is of vital importance in cases where most information is carried by the transients, for instance in evoked potentials measured commonly in electrophysiology. We show viability of our approach using nonline...
0805.0532v2
2008-05-08
Spin-Electric Coupling in Molecular Magnets
We study the triangular antiferromagnet Cu$_3$ in external electric fields, using symmetry group arguments and a Hubbard model approach. We identify a spin-electric coupling caused by an interplay between spin exchange, spin-orbit interaction, and the chirality of the underlying spin texture of the molecular magnet. Th...
0805.1158v1
2008-05-08
The viability of theories with matter coupled to the Ricci scalar
Recently there has been a proposal for modified gravitational f(R) actions which include a direct coupling between the matter action and the Ricci scalar, R. Of particular interest is the specific case where both the action and the coupling are linear in R. It is shown that such an action leads to a theory of gravity w...
0805.1160v2
2008-05-08
On the non-minimal gravitational coupling to matter
The connection between $f(R)$ theories of gravity and scalar-tensor models with a "physical" metric coupled to the scalar field is well known. In this work, we pursue the equivalence between a suitable scalar theory and a model that generalises the $f(R)$ scenario, encompassing both a non-trivial scalar curvature term ...
0805.1241v2
2008-05-08
Modified gravity with R-matter couplings and (non-)geodesic motion
We consider alternative theories of gravity with a direct coupling between matter and the Ricci scalar We study the relation between these theories and ordinary scalar-tensor gravity, or scalar-tensor theories which include non-standard couplings between the scalar and matter. We then analyze the motion of matter in su...
0805.1249v2
2008-05-17
Resolving disagreement for eta/s in a CFT plasma at finite coupling
The ratio of shear viscosity to entropy density in a strongly coupled CFT plasma can be computed using the AdS/CFT correspondence either from equilibrium correlation functions or from the Janik-Peschanski dual of the boost invariant plasma expansion. We point out that the previously found disagreement for eta/s at fini...
0805.2683v1
2008-05-22
On Asymptotic Stability of Solitary Waves in Discrete Schrödinger Equation Coupled to Nonlinear Oscillator
The long-time asymptotics is analyzed for finite energy solutions of the 1D discrete Schr\"odinger equation coupled to a nonlinear oscillator. The coupled system is invariant with respect to the phase rotation group. For initial states close to a solitary wave, the solution converges to a sum of another solitary wave a...
0805.3403v1
2008-05-22
Beyond the Chameleon Mechanism
As a result of non-linear self-interactions, in chameleon theories where the field couples to matter much more strongly than gravity does, the fifth force between two bodies with thin-shell is independent of their coupling to the field. As a consequence the bounds on the coupling coming from terrestrial tests of gravit...
0805.3430v1
2008-05-26
Coupling of electrons to the electromagnetic field in a localized basis
A simple formula is obtained for coupling electrons in a complex system to the electromagnetic field. It includes the effect of intra-atomic excitations and nuclear motion, and can be applied in. e.g., first-principles-based simulations of the coupled dynamics of electrons and nuclei in materials and molecules respondi...
0805.3803v2
2008-05-27
Strong coupling of light with one-dimensional quantum dot chain: from Rabi oscillations to Rabi waves
Interaction of traveling wave of classic light with 1D-chain of coupled quantum dots (QDs) in strong coupling regime has been theoretically considered. The effect of space propagation of Rabi oscillations in the form of traveling waves and wave packets has been predicted. Physical interpretation of the effect has been ...
0805.4094v1
2008-06-02
Low Dimensional Behavior of Large Systems of Globally Coupled Oscillators
It is shown that, in the infinite size limit, certain systems of globally coupled phase oscillators display low dimensional dynamics. In particular, we derive an explicit finite set of nonlinear ordinary differential equations for the macroscopic evolution of the systems considered. For example, an exact, closed form s...
0806.0004v1
2008-06-03
A gate-defined silicon quantum dot molecule
We report electron transport measurements of a silicon double dot formed in multi-gated metal-oxide-semiconductor structures with a 15-nm-thick silicon-on-insulator layer. Tunable tunnel coupling enables us to observe an excitation spectrum in weakly coupled dots and an energy level anticrossing in strongly coupled one...
0806.0422v1
2008-06-09
Implications of the anomalous top quark couplings in $B_s-\bar{B}_s$ mixing, $B \to X_s γ$ and top quark decays
Combined analysis of recent measured $\bs$ mixing and $B \to X_s \gamma$ decays provides constraints on the anomalous $\bar{t}sW$ couplings. We discuss the perspectives to examine the anomalous $\bar{t}sW$ couplings through CKM-suppressed $ t \to s W$ decays at the LHC.
0806.1389v2
2008-06-12
Towards the description of anisotropic plasma at strong coupling
We initiate a study of anisotropic plasma at strong coupling using the AdS/CFT correspondence. We construct an exact dual geometry which represents a static uniform but anisotropic system and find, that although it is singular, it allows for a notion of `incoming' boundary conditions. We study small fluctuations around...
0806.2141v2
2008-06-20
Quarkyonic matter in lattice QCD at strong coupling
We study the phase diagram of quark matter at finite temperature and density in the strong coupling lattice QCD with one species of unrooted staggered fermions including finite coupling ($1/g^2$) effects for color SU($N_c$). We find that we may have partially chiral restored medium density matter at $N_c=3$, which woul...
0806.3357v3
2008-06-22
Application of the GALI Method to Localization Dynamics in Nonlinear Systems
We investigate localization phenomena and stability properties of quasiperiodic oscillations in $N$ degree of freedom Hamiltonian systems and $N$ coupled symplectic maps. In particular, we study an example of a parametrically driven Hamiltonian lattice with only quartic coupling terms and a system of $N$ coupled standa...
0806.3563v1
2008-06-23
Counterion correlations near charged surfaces: from the weak to the strong coupling regime
A simple field theory approach is developed to model the properties of charged, dielectric bodies and their associated counterions. This predictive theory is able to accurately describe the properties of systems (as compared to computer simulation data) from the weak coupling limit, where the Poisson-Boltzmann theory w...
0806.3716v3
2008-06-24
Squarks and gluinos at a TeV e+e- collider: Testing the identity of Yukawa and gauge couplings in SUSY-QCD
Supersymmetry predicts the identity of Yukawa and gauge couplings in the QCD sector: quark-squark-gluino = squark-squark-gluon = quark-quark-gluon. We examine whether the quark-squark-gluino Yukawa coupling can be determined, by methods complementary to LHC, by analyzing squark-gluino final states at a TeV e+e- collide...
0806.3875v1
2008-06-24
Observation of lasing without inversion in a hot rubidium vapor under electromagnetically-induced transparency conditions
We have observed CW lasing without inversion in a gas of hot rubidium atoms in an optical cavity under conditions of electromagnetically-induced transparency (EIT). The medium is pumped coherently and resonantly by a single ``coupling'' beam which also produces EIT in the lasing transition. The steady-state intensity e...
0806.3993v1
2008-06-30
Bolometric Detection of Quantum Shot Noise in Coupled Mesoscopic Systems
We present a new scheme to detect the quantum shot noise in coupled mesoscopic systems. By applying the noise thermometry to the capacitively coupled quantum point contacts (QPCs) we prove that the noise temperature of one QPC is in perfect proportion to that of the other QPC which is driven to non-equilibrium to gener...
0806.4805v1
2008-08-07
Probing the ZZgamma and Zgammagamma Couplings Through the Process e+e- --> nu anti-nu gamma
We study the sensitivity for testing the anomalous triple gauge couplings $ZZ\gamma$ and $Z\gamma\gamma$ via the process $e^+e^-\to \nu \bar\nu \gamma$ at high energy linear colliders. For integrated luminosities of 500 $fb^{-1}$ and center of mass energies between 0.5 and 1.5 $TeV$, we find that this process can provi...
0808.0945v2
2008-08-07
On the complete integrability and linearization of nonlinear ordinary differential equations - Part V: Linearization of coupled second order equations
Linearization of coupled second order nonlinear ordinary differential equations (SNODEs) is one of the open and challenging problems in the theory of differential equations. In this paper we describe a simple and straightforward method to derive linearizing transformations for a class of two coupled SNODEs. Our procedu...
0808.0969v2
2008-08-09
Quantum frustration of dissipation by a spin bath
We investigate the evolution of a central spin coupled to a spin bath without internal dynamics. We compare the cases where the bath couples to one or two components of the spin. It is found that the central spin dynamics is enhanced in the latter case, which may be interpreted as a frustration of dissipation. However,...
0808.1377v1
2008-08-21
Unconventional pairing in excitonic condensates under spin-orbit coupling
It is shown that the Rashba and Dresselhaus spin orbit couplings enhance the conclusive power in the experiments on the excitonic condensed state by at least three low temperature effects. First, spin orbit coupling facilitates the photoluminescense measurements via enhancing the bright contribution in the otherwise do...
0808.2900v2
2008-08-28
Magnetoelectric coupling in the cubic ferrimagnet Cu2OSeO3
We have investigated the magnetoelectric coupling in the lone pair containing piezoelectric ferrimagnet Cu2OSeO3. Significant magnetocapacitance develops in the magnetically ordered state (TC = 60 K). We find critical behavior near TC and a divergence near the metamagnetic transition at 500 Oe. High-resolution X-ray an...
0808.3955v1
2008-09-01
Quantum phase diagram of a spin-1/2 antiferromagnetic chain with magnetic impurity
We present the renormalization group (RG) flow diagram of a spin-half antiferromagnetic chain with magnetic impurity and one altered link. In this two parameters (competing interactions) model, one can find the complex phase diagram with many interesting fixed points. There is no evidence of intermediate stable fixed p...
0809.0173v1
2008-09-04
$B_d-\bar{B}_d$ mixing vs. $B_s-\bar{B}_s$ mixing with the anomalous $Wtb$ couplings
We explore the effects of the anomalous $tbW$ couplings on the $\bd$ mixing and recently measured $\bs$ mixing. The combined analysis of mixings via box diagrams with penguin decays provides strong constraints on the anomalous top quark couplings. We find the bound from the $\bd$ mixing data is stronger than that from ...
0809.0751v2
2008-09-26
Synchrony-optimized Networks of Non-identical Kuramoto Oscillators
In this letter we discuss a method for generating synchrony-optimized coupling architectures of Kuramoto oscillators with a heterogeneous distribution of native frequencies. The method allows us to relate the properties of the coupling network to its synchronizability. These relations were previously only established f...
0809.4531v1
2008-10-06
High-energy jet quenching in weakly-coupled quark-gluon plasmas
$\hat q$ is the average squared transverse momentum transfer per unit length to a high-energy particle traversing a QCD medium such as a quark-gluon plasma. We find the (UV-regulated) value of $\hat q$ to leading order in the weak coupling limit, $\alphas(T) \ll 1$. We then use this value to generalize previous analyti...
0810.1026v1
2008-10-07
How to compute the thermal quarkonium spectral function from first principles?
In the limit of a high temperature T and a large quark-mass M, implying a small gauge coupling g, the heavy quark contribution to the spectral function of the electromagnetic current can be computed systematically in the weak-coupling expansion. We argue that the scale hierarchy relevant for addressing the disappearanc...
0810.1112v1
2008-10-08
Quantum fluctuations in trapped time-dependent Bose-Einstein condensates
Quantum fluctuations in time-dependent, harmonically-trapped Bose-Einstein condensates are studied within Bogoliubov theory. An eigenmode expansion of the linear field operators permits the diagonalization of the Bogoliubov-de Gennes equation for a stationary condensate. When trap frequency or interaction strength are ...
0810.1347v1
2008-10-15
Synchronization Stability of Coupled Near-Identical Oscillator Network
We derive variational equations to analyze the stability of synchronization for coupled near-identical oscillators. To study the effect of parameter mismatch on the stability in a general fashion, we define master stability equations and associated master stability functions, which are independent of the network struct...
0810.2775v1
2008-10-20
Diboson Production and Couplings
We present the most recent cross section measurements for WW and WZ production in proton-antiproton collisions with sqrt(s) = 1.96 TeV at the Fermilab Tevatron in final states with two or three leptons, respectively, along with limits on WWZ triple gauge couplings. We also present the combined search for WW and WZ prod...
0810.3443v1
2008-10-22
Topological Symmetry And Existence of Partial Synchronization
We study the relationship between the partial synchronous (PaS) state and the coupling structure in general dynamical systems. By the exact proof, we find the sufficient and necessary condition of the existence of PaS state for the coupling structure. Our result shows that the symmetry of the coupling structure is not ...
0810.4098v1
2008-10-23
Charged current reactions in the NuSOnG and a test of neutrino-W couplings
We explore the physics potential of NuSOnG experiment to probe new physics contributions to $W\mu\nu_\mu$ couplings in inverse muon decay and charged current deep inelastic scattering processes. We show that NuSOnG provides two order of magnitude improvement in $W\mu\nu_\mu$ compared to LEP bound at 95% C.L.. Combining...
0810.4318v1
2008-10-24
A quantum interface between light and nuclear spins in quantum dots
The coherent coupling of flying photonic qubits to stationary matter-based qubits is an essential building block for quantum communication networks. We show how such a quantum interface can be realized between a traveling-wave optical field and the polarized nuclear spins in a singly charged quantum dot strongly couple...
0810.4488v3
2008-10-25
The $Λ$-$Σ$ coupling effect in the neutron-rich $Λ$-hypernucleus $_Λ^{10}$Li by microscopic shell model
We investigate the structure of the neutron-rich $\Lambda$-hypernucleus $_{\Lambda}^{10}$Li by using microscopic shell-model calculations considering a $\Lambda$-$\Sigma$ coupling effect. The calculated $\Sigma$-mixing probability in the $_{\Lambda}^{10}$Li ground state is found to be about 0.34 % which is coherently e...
0810.4591v2
2008-10-28
Gauge coupling constant, compositeness and supersymmetry
We point out the possibility that the magnitude of the bare gauge coupling constant is determined theoretically in a composite model of all particles in SUSY theories. We show explicitly in two space-time dimensions that the NL/L SUSY relation (i.e., a SUSY compositeness condition for all particles) between N = 2 LSUSY...
0810.5006v4
2008-10-30
Direct Evidence for Multiferroic Magnetoelectric Coupling in 0.9BiFeO3-0.1BaTiO3
Magnetic, dielectric and calorimetric studies on 0.9BiFeO3-0.1BaTiO3 indicate strong magnetoelectric coupling. XRD studies reveal a very remarkable change in the rhombohedral distortion angle and a significant shift in the atomic positions at the magnetic Tc due to an isostructural phase transition. The calculated pola...
0810.5418v1
2008-10-30
The effect of dipole-dipole interaction for two atoms with different couplings in non-Markovian environment
Using the nonperturbative method, we study the exact entanglement dynamics of two two-level dipole-dipole interacting atoms coupled to a common non-Markovian reservoir with different coupling strengths. Besides analyzing the conditions for the existence of steady state, we find, though the dipole-dipole interaction cou...
0810.5420v1
2008-10-30
Nonequilibrium dynamics of polariton entanglement in a cluster of coupled traps
We study in detail the generation and relaxation of quantum coherences (entanglement) in a system of coupled polariton traps. By exploiting a Lie algebraic based super-operator technique we provide an analytical exact solution for the Markovian dissipative dynamics (Master equation) of such system which is valid for ar...
0810.5485v1
2008-11-03
Coupling of nitrogen-vacancy centers in diamond to a GaP waveguide
The optical coupling of guided modes in a GaP waveguide to nitrogen-vacancy (NV) centers in diamond is demonstrated. The electric field penetration into diamond and the loss of the guided mode are measured. The results indicate that the GaP-diamond system could be useful for realizing coupled microcavity-NV devices for...
0811.0328v1
2008-11-04
Amplitude-Phase Coupling in a Spin-Torque Nano-Oscillator
The spin-torque nano-oscillator in the presence of thermal fluctuation is described by the normal form of the Hopf bifurcation with an additive white noise. By the application of the reduction method, the amplitude-phase coupling factor, which has a significant effect on the power spectrum of the spin-torque nano-oscil...
0811.0425v1
2008-11-04
Jet quenching with running coupling including radiative and collisional energy losses
We calculate the nuclear modification factor for RHIC and LHC conditions accounting for the radiative and collisional parton energy loss with the running coupling constant.We find that the RHIC data can be explained both in the scenario with the chemically equilibrium quark-gluon plasma and purely gluonic plasma with s...
0811.0445v2
2008-11-06
Motion of test bodies in theories with nonminimal coupling
We derive the equations of motion of test bodies for a theory with nonminimal coupling by means of a multipole method. The propagation equations for pole-dipole particles are worked out for a gravity theory with a very general coupling between the curvature scalar and the matter fields. Our results allow for a systemat...
0811.0913v2
2008-11-07
Atomic entanglement sudden death in a strongly driven cavity QED system
We study the entanglement dynamics of strongly driven atoms off-resonantly coupled with cavity fields. We consider conditions characterized not only by the atom-field coupling but also by the atom-field detuning. By studying two different models within the framework of cavity QED, we show that the so-called atomic enta...
0811.1079v2
2008-11-15
Plykin-like attractor in non-autonomous coupled oscillators
A system of two coupled non-autonomous oscillators is considered. Dynamics of complex amplitudes is governed by differential equations with periodic piecewise continuous dependence of the coefficients on time. The Poincar\'{e} map is derived explicitly. With exclusion of the overall phase, on which the evolution of oth...
0811.2489v1
2008-11-17
${Σ_{Q}Λ_{Q}π}$ Coupling Constant in Light Cone QCD Sum Rules
The strong coupling constants $g_{{\Sigma_{Q}\Lambda_{Q}\pi}}$ ($Q=b$ and $c$) are studied in the framework of the light cone QCD sum rules using the most general form of the baryonic currents. The predicted coupling constants are used to estimate the decay widths for the $\Sigma_{Q}\longrightarrow\Lambda_{Q}\pi$ decay...
0811.2695v2
2008-11-17
Correlated electron tunneling through two separate quantum dot systems with strong capacitive interdot coupling
A system consisting of two independently contacted quantum dots with strong electrostatic interaction shows interdot Coulomb blockade when the dots are weakly tunnel coupled to their leads. It is studied experimentally how the blockade can be overcome by correlated tunneling when tunnel coupling to the leads increases....
0811.2697v1
2008-11-20
Reconstructing a String-Inspired Non-minimally Coupled Quintom Model
Motivated by the recent work of Zhang and Chen \cite{bin}, we generalize their work to the non-minimally coupled case. We consider a quintom model of dark energy with a single scalar field $T$ given by a Lagrangian which inspired by tachyonic Lagrangian in string theory. We consider non-minimal coupling of tachyon fiel...
0811.3343v1
2008-11-30
Collective dynamical response of coupled oscillators with any network structure
We formulate a reduction theory that describes the response of an oscillator network as a whole to external forcing applied nonuniformly to its constituent oscillators. The phase description of multiple oscillator networks coupled weakly is also developed. General formulae for the collective phase sensitivity and the e...
0812.0118v1
2008-12-04
Heavy-quark energy loss and thermalization in a strongly coupled SYM plasma
Using the AdS/CFT correspondence, we compute the radiative energy loss of a slowly decelerating heavy quark with mass M moving through a supersymmetric Yang Mills (SYM) plasma at temperature T at large t'Hooft coupling \lambda. The calculation is carried out in terms of perturbation in \sqrt{\lambda}T/M, and the rate o...
0812.1051v1
2008-12-05
Phase-diffusion dynamics in weakly coupled Bose-Einstein condensates
We study the phase-sensitivity of collisional phase-diffusion between weakly coupled Bose-Einstein condensates, using a semiclassical picture of the two-mode Bose-Hubbard model. When weak-coupling is allowed, zero relative phase locking is attained in the Josephson-Fock transition regime, whereas a $\pi$ relative phase...
0812.1204v2
2008-12-12
Time-resolved lasing action from single and coupled photonic crystal nanocavity array lasers emitting in the telecom-band
We measure the lasing dynamics of single and coupled photonic crystal nanocavity array lasers fabricated in the indium gallium arsenide phosphide material system. Under short optical excitation, single cavity lasers produce pulses as fast as 11 ps (FWHM), while coupled cavity lasers show significantly longer lasing dur...
0812.2287v1
2008-12-16
Equivalence between supersymmetric self-dual and Maxwell-Chern-Simons models coupled to a matter spinor superfield
We study the duality of the supersymmetric self-dual and Maxwell-Chern-Simons theories coupled to a fermionic matter superfield, using a master action. This approach evades the difficulties inherent to the quartic couplings that appear when matter is represented by a scalar superfield. The price is that the spinorial m...
0812.3134v2
2008-12-19
Origin of the Ising Ferrimagnetism and Spin-Charge Coupling in LuFe2O4
The spin ordering and spin-charge coupling in LuFe2O4 were investigated on the basis of density functional calculations and Monte Carlo simulations. The 2:1 ferrimagnetism arises from the strong antiferromagnetic intra-sheet Fe3+-Fe3+ and Fe3+ -Fe2+ as well as some substantial antiferromagnetic Fe2+-Fe3+ inter-sheet sp...
0812.3897v1
2008-12-28
Yukawa Couplings and Effective Interactions in Gauge-Higgs Unification
The wave functions and Yukawa couplings of the top and bottom quarks in the SO(5) x U(1) gauge-Higgs unification model are determined. The result is summarized in the effective interactions for \hat \theta_H(x) = \theta_H + H(x)/f_H where \theta_H is the Wilson line phase and H(x) is the 4D Higgs field. The Yukawa, WWH...
0812.4782v3
2008-12-31
Effects of low-frequency noise cross-correlations in coupled superconducting qubits
We study the effects of correlated low frequency noise sources acting on a two qubit gate in a fixed coupling scheme. A phenomenological model for the spatial and cross-talk correlations is introduced. The decoherence inside the SWAP subspace is analysed by combining analytic results based on the adiabatic approximatio...
0901.0083v1
2008-12-31
Generating solutions via sigma-models
We review recent development of solution-generating techniques for four and five-dimensional Einstein equations coupled to vector and scalar fields. This includes D=4 Einstein-Maxwell-dilaton-axion theory with multiple vector fields, D=5 Einstein-Maxwell gravity with the Chern-Simons term (minimal five-dimensional supe...
0901.0098v1
2009-01-05
Janus and Multifaced Supersymmetric Theories II
We explore the physics of supersymmetric Janus gauge theories in four dimension with spatial dependent coupling constants, e^2 and theta. For the 8 supersymmetric case, we study the vacuum and BPS spectrum, and the physics of a sharp interface where the couple constants jump. We also find less supersymmetric cases eith...
0901.0506v3
2009-01-07
Interplay of coupling and superradiant emmision in the optical response of a double quantum dot
We study theoretically the optical response of a double quantum dot structure to an ultrafast optical excitation. We show that the interplay of a specific type of coupling between the dots and their collective interaction with the radiative environment leads to very characteristic features in the time-resolved luminesc...
0901.0879v2
2009-01-08
Interlayer coupling enhanced by the interface roughness
Previous experiment on Fe/Cr/Fe(001) trilayers reported a surprising observation that the interlayer exchange coupling could be enhanced drastically by the bombardment of irradiation even at low fluences. We propose that it is due to the resonant states in the spacer, made possible when the topography of both interface...
0901.0965v1
2009-01-11
A non-linear hardening model based on two coupled internal hardening variables: formulation and implementation
An elasto-plasticity model with coupled hardening variables of strain type is presented. In the theoretical framework of generalized associativity, the formulation of this model is based on the introduction of two hardening variables with a coupled evolution. Even if the corresponding hardening rules are linear, the st...
0901.1449v1
2009-01-14
Interface coupling properties and reflection of bulk spin waves from biaxial multilayer ferromagnetic media
The reflection coefficient of bulk spin waves from multilayer ferromagnetic structure with periodically modulated parameters of exchange interaction, uniaxial and rhombic magnetic anisotropy and saturation magnetization is calculated with a non-ideal coupling between layers. The strong dependence of spin-wave reflectio...
0901.2012v1
2009-01-15
Fermions Coupled to Emergent Noncommutative Gravity
We study the coupling of fermions to Yang-Mills matrix models in the framework of emergent noncommutative gravity. It is shown that the matrix model action provides an appropriate coupling for fermions to gravity, albeit with a non-standard spin-connection. Integrating out the fermions in a nontrivial geometrical backg...
0901.2322v1
2009-01-16
Synchronization of dissipative dynamical systems driven by non-Gaussian Levy noises
Dynamical systems driven by Gaussian noises have been considered extensively in modeling, simulation and theory. However, complex systems in engineering and science are often subject to non-Gaussian fluctuations or uncertainties. A coupled dynamical system under non- Gaussian Levy noises is considered. After discussing...
0901.2446v1
2009-01-16
Magnetic Moment Coupling to Circularly Polarized Photons
Exact stationary solutions of the wave equation are obtained to describe the interaction between magnetic moment of elementary particle and circularly polarized photons. The obtained solutions substantially modify the conventional model of field-matter interaction. It follows from them that magnetic moment couples to p...
0901.2501v3
2009-01-23
Quantum jumps and spin dynamics of interacting atoms in a strongly coupled atom-cavity system
We experimentally investigate the spin dynamics of one and two neutral atoms strongly coupled to a high finesse optical cavity. We observe quantum jumps between hyperfine ground states of a single atom. The interaction-induced normal mode splitting of the atom-cavity system is measured via the atomic excitation. Moreov...
0901.3738v2
2009-01-30
Sensitivity to the Higgs Self-coupling Using the ZHH Channel
The Standard Model predicts the value of the Higgs self-coupling but it cannot be measured at LHC. This measurement requires a machine such as the proposed International Linear Collider. Here, the sensitivity to the Higgs self-coupling is evaluated using the ZHH to six jets channel for a Higgs mass of 120GeV/c^{2}. Ful...
0901.4895v1
2009-01-31
Heavy Charged Gauge Bosons with General CP Violating Couplings
Heavy gauge bosons such as $W^{\prime}$ are expected to exist in many extensions of the Standard Model. In this paper, it is shown that the most general Lagrangian for the interaction of $W^{\prime}$ with top and bottom quarks which consists of V-A and V+A structure with in general complex couplings produces an Electri...
0902.0059v2
2009-02-06
Singular perturbation near mode-coupling transition
We study the simplest mode-coupling equation which describes the time correlation function of the spherical p-spin glass model. We formulate a systematic perturbation theory near the mode-coupling transition point by introducing multiple time scales. In this formulation, the invariance with respect to the dilatation of...
0902.1010v2
2009-02-26
Qubit protection in nuclear-spin quantum dot memories
We present a mechanism to protect quantum information stored in an ensemble of nuclear spins in a semiconductor quantum dot. When the dot is charged the nuclei interact with the spin of the excess electron through the hyperfine coupling. If this coupling is made off-resonant it leads to an energy gap between the collec...
0902.4566v1
2009-02-27
Quantum phase transition in quantum dot trimers
We investigate a system of three tunnel-coupled semiconductor quantum dots in a triangular geometry, one of which is connected to a metallic lead, in the regime where each dot is essentially singly occupied. Both ferro- and antiferromagnetic spin-1/2 Kondo regimes, separated by a quantum phase transition, are shown to ...
0902.4816v1