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2003-09-22
Fast two-bit operations in inductively coupled flux qubits
A central problem for implementing efficient quantum computing is how to realize fast operations (both one- and two-bit ones). However, this is difficult to achieve for a collection of qubits, especially for those separated far away, because the interbit coupling is usually much weaker than the intrabit coupling. Here ...
0309491v3
2004-01-12
The Effects of the interfacial Pseudo-spin Coupling Fluctuation on the Dielectric Property of a Ferroelectric Superlattice
Using effective-field theory with correlations, we investigate the effects of interfacial pseudo-spin coupling fluctuations on the susceptibility and polarization of ferroelectric superlattices within the framework of transverse Ising model. It is found that the interfacial coupling fluctuations increase the susceptibi...
0401168v3
2004-08-26
Collective synchronization in spatially extended systems of coupled oscillators with random frequencies
We study collective behavior of locally coupled limit-cycle oscillators with random intrinsic frequencies, spatially extended over $d$-dimensional hypercubic lattices. Phase synchronization as well as frequency entrainment are explored analytically in the linear (strong-coupling) regime and numerically in the nonlinear...
0408553v1
2004-10-11
Dispersion of incoherent spectral features in systems with strong electron-phonon coupling
We study (inverse) photoemission from systems with strong coupling of doped carriers to phonons. Using an adiabatic approximation, we develop a method for calculating spectra. This method is particularly simple for systems where the electron-phonon coupling can be neglected in the initial state, e.g., the undoped t-J m...
0410247v1
2005-01-05
Direct Josephson coupling between superconducting flux qubits
We have demonstrated strong antiferromagnetic coupling between two three-junction flux qubits based on a shared Josephson junction, and therefore not limited by the small inductances of the qubit loops. The coupling sign and magnitude were measured by coupling the system to a high-quality superconducting tank circuit. ...
0501085v2
2005-03-23
Indirect exchange coupling between magnetic adatoms in carbon nanotubes
The long range character of the exchange coupling between localized magnetic moments indirectly mediated by the conduction electrons of metallic hosts can play a significant role in determining the magnetic order of low-dimensional structures. Here we consider how this indirect coupling influences the magnetic alignmen...
0503589v1
2005-05-23
Synchronizations in small-world networks of spiking neurons: Diffusive versus sigmoid couplings
By using a semi-analytical dynamical mean-field approximation previously proposed by the author [H. Hasegawa, Phys. Rev. E, {\bf 70}, 066107 (2004)], we have studied the synchronization of stochastic, small-world (SW) networks of FitzHugh-Nagumo neurons with diffusive couplings. The difference and similarity between re...
0505543v3
2005-12-28
Decoherence dynamics of a qubit coupled to a quantum two-level system
We study the decoherence dynamics of a qubit coupled to a quantum two-level system (TLS) in addition to its weak coupling to a background environment. We analyze the different regimes of behaviour that arise as the values of the different parameters are varied. We classify those regimes as two weak-coupling regimes, wh...
0512677v3
2006-01-17
Spin Hot Spots in vertically-coupled Few-electron Quantum Dots
The effects of spin-orbit (SO) coupling arising from the confinement potential in single and two vertically-coupled quantum dots have been investigated. Our work indicates that a dot containing a single electron shows the lifting of the degeneracy of dipole-allowed transitions at B=0 due to the SO coupling which disapp...
0601390v1
2006-04-25
Public-channel cryptography based on mutual chaos pass filters
We study the mutual coupling of chaotic lasers and observe both experimentally and in numeric simulations, that there exists a regime of parameters for which two mutually coupled chaotic lasers establish isochronal synchronization, while a third laser coupled unidirectionally to one of the pair, does not synchronize. W...
0604569v1
2006-11-19
Magnetic coupling in CoCr_2O_4 and MnCr_2O_4: an LSDA+U study
We present a first principles LSDA+U study of the magnetic coupling constants in the spinel magnets CoCr_2O_4 and MnCr_2O_4. Our calculated coupling constants highlight the possible importance of AA interactions in spinel systems with magnetic ions on both A and B sites. Furthermore, we show that a careful analysis of ...
0611502v3
2006-06-26
Coupled quintessence and curvature-assisted acceleration
Spatially homogeneous models with a scalar field non-minimally coupled to the space-time curvature or to the ordinary matter content are analysed with respect to late-time asymptotic behaviour, in particular to accelerated expansion and isotropization. It is found that a direct coupling to the curvature leads to asympt...
0606113v2
2001-04-18
Measurement of Triple Gauge-Boson Couplings at LEP up to 189GeV
The triple gauge-boson couplings involving the W are determined using data samples collected with the ALEPH detector at mean centre-of-mass energies of 183 GeV and 189 GeV, corresponding to integrated luminosities of 57 pb^-1 and 174 pb^-1, respectively. The couplings, g^Z_1, Kappa_gamma and lambda_gamma, are measured ...
0104034v1
2003-08-27
Measurement of charged current triple gauge boson couplings using W pairs at LEP
Triple gauge boson couplings are measured from W-pair and single photon events recorded by the OPAL detector at LEP at center-of-mass energies between 183 - 209 GeV with a total integrated luminosity of 680 inverse picobarns. Only CP-conserving couplings are considered and SU(2)xU(1) relations between the WWZ and the W...
0308067v1
2005-11-20
Running couplings in equivariantly gauge-fixed SU(N) Yang--Mills theories
In equivariantly gauge-fixed SU(N) Yang--Mills theories, the gauge symmetry is only partially fixed, leaving a subgroup $H\subset SU(N)$ unfixed. Such theories avoid Neuberger's nogo theorem if the subgroup $H$ contains at least the Cartan subgroup $U(1)^{N-1}$, and they are thus non-perturbatively well defined if regu...
0511042v1
1993-12-07
How Big Can Anomalous W Couplings Be?
Conventional wisdom has it that anomalous gauge-boson self-couplings can be at most a percent or so in size. We test this wisdom by computing these couplings at one loop in a generic renormalizable model of new physics. (For technical reasons we consider the CP-violating couplings here, but our results apply more gener...
9312238v2
1994-02-18
Effects of technicolor on standard model running couplings
We discuss the running couplings in the standard model, SU(3$)_C \times $SU(2$)_L \times $U(1$)_Y$, when the Higgs sector is replaced by SU($N_{TC})$ technicolor. Particular attention is given to the running of the couplings at momentum scales where technicolor is nonperturbative, and in this region we apply a relativi...
9402319v1
1997-07-25
Strong Unification
We investigate the possibility that unification occurs at strong coupling. We show that, despite the fact the couplings pass through a strong coupling regime, accurate predictions for their low energy values are possible because the couplings of the theory flow to infrared fixed points. We determine the low-energy QCD ...
9707462v2
1999-02-19
Infra-red stable fixed points of R-parity violating Yukawa couplings in supersymmetric models
We investigate the infra-red stable fixed points of the Yukawa couplings in the minimal version of the supersymmetric standard model with R-parity violation. Retaining only the R-parity violating couplings of higher generations, we analytically study the solutions of the renormalization group equations of these couplin...
9902405v3
1999-06-10
Gauge Coupling Unification with Extra Dimensions and Gravitational Scale Effects
We study gauge coupling unification in the presence of extra dimensions compactified at a few TeV. Achieving unification requires a large number of gauge boson Kaluza-Klein excitations lighter than the string scale, such that the higher-dimensional gauge couplings are O(1) in string scale units. Corrections to the gaug...
9906327v2
1999-10-04
Preheating of the nonminimally coupled inflaton field
We investigate preheating of an inflaton field $\phi$ coupled nonminimally to a spacetime curvature. In the case of a self-coupling inflaton potential $V(\phi)=\lambda \phi^4/4$, the dynamics of preheating changes by the effect of the negative $\xi$. We find that the nonminimal coupling works in two ways. First, sinc...
9910214v2
2000-04-27
Higgs sector and R-parity breaking couplings in models with broken U(1)_B-L gauge symmetry
Four different supersymmetric models based on SU(2)_L X U(1)_R X U(1)_B-L and SU(2)_L X SU(2)_R X U(1)_B-L gauge symmetry groups are studied. U(1)_B-L symmetry is broken spontaneously by a vacuum expectation value (VEV) of a sneutrino field. The right-handed gauge bosons may obtain their mass solely by sneutrino VEV. T...
0004239v1
2000-11-22
Infrared Fixed Point Structure in Minimal Supersymmetric Standard Model with Baryon and Lepton Number Violation
We study in detail the renomalization group evolution of Yukawa couplings and soft supersymmetry breaking trilinear couplings in the minimal supersymmetric standard model with baryon and lepton number violation. We obtain the exact solutions of these equations in a closed form, and then depict the infrared fixed point ...
0011274v2
2001-02-10
New analytic running coupling in spacelike and timelike regions
The new model for the QCD analytic running coupling, proposed recently, is extended to the timelike region. This running coupling naturally arises under unification of the analytic approach to QCD and the renormalization group (RG) formalism. A new method for determining the coefficients of the "analytized" RG equation...
0102124v2
2003-06-25
Probing triple gauge couplings with transverse beam polarisation in e+e- -> W+W-
The prospects of measuring triple gauge couplings in W pair production at future linear colliders with transverse beam polarisation are studied. We consider CP conserving and CP violating couplings with both real and imaginary parts. The maximum achievable sensitivity in a simultaneous measurement of all couplings is d...
0306247v2
2004-06-29
Extracting Higgs boson couplings from LHC data
We show how LHC Higgs boson production and decay data can be used to extract gauge and fermion couplings of Higgs bosons. We show that very mild theoretical assumptions, which are valid in general multi-Higgs doublet models, are sufficient to allow the extraction of absolute values for the couplings rather than just ra...
0406323v1
2005-12-24
Pseudoscalar Photon Mixing In A Magnetized Medium
Axions are pseudo-scalar particles, those arise because of breaking of Peccei Queen (PQ) symmetry. Axions have a tree level coupling to two photons. As a consequence there exists a tree level coupling of axion to photon in a magnetic field. However, in an external magnetic field, there exists a new loop induced, axion ...
0512323v1
2007-01-17
Implications of Canonical Gauge Coupling Unification in High-Scale Supersymmetry Breaking
We systematically construct two kinds of models with canonical gauge coupling unification and universal high-scale supersymmetry breaking. In the first we introduce standard vector-like particles while in the second we also include non-standard vector-like particles. We require that the gauge coupling unification scale...
0701136v1
2007-03-19
Anomalous Quartic $WWγγ$ and $ZZγγ$ Couplings in $eγ$ Collision With Initial Beams and Final State Polarizations
The constraints on the anomalous quartic $WW\gamma\gamma$ and $ZZ\gamma\gamma$ gauge boson couplings are investigated through the processes $e\gamma\to W^{-}\gamma\nu_{e}$ and $e\gamma\to Z\gamma e$. Considering the longitudinal and transverse polarization states of the final W or Z boson and incoming beam polarization...
0703201v1
2001-09-13
Non-minimal coupling for spin 3/2 fields
The problem of the electromagnetic coupling for spin 3/2 fields is discussed. Following supergravity and some recent works in the field of classical supersymmetric particles, we find that the electromagnetic coupling must not obey a minimal coupling in the sense that one needs to consider not only the electromagnetic p...
0109104v1
2003-02-14
Yukawa couplings in intersecting D-brane models
We compute the Yukawa couplings among chiral fields in toroidal Type II compactifications with wrapping D6-branes intersecting at angles. Those models can yield realistic standard model spectrum living at the intersections. The Yukawa couplings depend both on the Kahler and open string moduli but not on the complex str...
0302105v2
2005-04-04
Flavor structure and coupling selection rule from intersecting D-branes
We study flavor structure and the coupling selection rule in intersecting D-brane configurations. We formulate the selection rule for Yukawa couplings and its extensions to generic n-point couplings. We investigate the possible flavor structure, which can appear from intersecting D-brane configuration, and it is found ...
0504019v1
2007-03-26
Gravitating Monopole-Antimonopole Systems at Large Scalar Coupling
We discuss static axially symmetric solutions of SU(2) Einstein-Yang-Mills-Higgs theory for large scalar coupling. These regular asymptotically flat solutions represent monopole-antimonopole chain and vortex ring solutions, as well as new configurations, present only for larger values of the scalar coupling. When gravi...
0703232v1
2004-08-10
Ergodic Dynamics of the Coupled Quasigeostrophic Flow-Energy Balance System
The authors consider a mathematical model for the coupled atmosphere-ocean system, namely, the coupled quasigeostrophic flow-energy balance model. This model consists of the large scale quasigeostrophic oceanic flow model and the transport equation for oceanic temperature, coupled with an atmospheric energy balance mod...
0408135v1
2005-11-23
Discrete vector on-site vortices
We study discrete vortices in coupled discrete nonlinear Schrodinger equations. We focus on the vortex cross configuration that has been experimentally observed in photorefractive crystals. Stability of the single-component vortex cross in the anti-continuum limit of small coupling between lattice nodes is proved. In t...
0511586v1
2006-11-21
Metastability in Interacting Nonlinear Stochastic Differential Equations I: From Weak Coupling to Synchronisation
We consider the dynamics of a periodic chain of N coupled overdamped particles under the influence of noise. Each particle is subjected to a bistable local potential, to a linear coupling with its nearest neighbours, and to an independent source of white noise. We show that as the coupling strength increases, the numbe...
0611647v2
2003-07-22
Synchronized clusters in coupled map networks: Stability analysis
We study self-organized (s-) and driven (d-) synchronization in coupled map networks for some simple networks, namely two and three node networks and their natural generalization to globally coupled and complete bipartite networks. We use both linear stability analysis and Lyapunov function approach for this study and ...
0307037v1
2006-08-09
Delayed-mutual coupling dynamics of lasers: scaling laws and resonances
We consider a model for two lasers that are mutually coupled optoelectronically by modulating the pump of one laser with the intensity deviations of the other. Signal propagation time in the optoelectronic loop causes a significant delay leading to the onset of oscillatory output. Multiscale perturbation methods are us...
0608015v1
1999-04-18
$πNN$ coupling determined beyond the chiral limit
Within the conventional QCD sum rules, we calculate the $\pi NN$ coupling constant, $g_{\pi N}$, beyond the chiral limit using two-point correlation function with a pion. We consider the Dirac structure, $i\gamma_5$, at $m_\pi^2$ order, which has clear dependence on the PS and PV coupling schemes for the pion-nucleon i...
9904049v2
2001-09-21
An Analysis of the $^{12}$C+$^{24}$Mg Reaction Using A New Coupling Potential
We introduce a new coupling potential to explain the experimental data for the $^{12}$C+$^{24}$Mg system at numerous energies in the laboratory system from 16.0 MeV to 24.0 MeV. This new coupled-channels based approach involves replacing the usual first derivative coupling potential by a new, second-derivative coupling...
0109064v1
2000-12-06
Perturbative treatment of intercenter coupling in Redfield theory
The quantum dynamics of coupled subsystems connected to a thermal bath is studied. In some of the earlier work the effect of intercenter coupling on the dissipative part was neglected. This is equivalent to a zeroth-order perturbative expansion of the damping term with respect to the intercenter coupling. It is shown n...
0012012v1
2005-04-14
Coupling into the slow light mode in slab-type photonic crystal waveguides
Coupling of external light signals into a photonic crystal waveguide becomes increasingly inefficient as the group velocity of the waveguiding mode slows down. We have systematically studied the efficiency of coupling in the slow light regime for samples with different truncations of the photonic lattice at the couplin...
0504102v4
2003-07-18
Entanglement production in coupled chaotic systems : Case of the Kicked Tops
Entanglement production in coupled chaotic systems is studied with the help of kicked tops. Deriving the correct classical map, we have used the reduced Husimi function, the Husimi function of the reduced density matrix, to visualize the possible behaviors of a wavepacket. We have studied a phase space based measure of...
0307134v2
2007-09-05
Strain dependent twist-stretch elasticity in chiral filaments
Coupling between axial and torsional degrees of freedom often modifies the conformation and expression of natural and synthetic filamentous aggregates. Recent studies on chiral single-walled carbon nanotubes and B-DNA reveal a reversal in the sign of the twist-stretch coupling at large strains. The similarity in the re...
0709.0558v1
2007-10-09
Direct Detection of Non-Chiral Dark Matter
Direct detection experiments rule out fermion dark matter that is a chiral representation of the electroweak gauge group. Non-chiral real, complex and singlet representations, however, provide viable fermion dark matter candidates. Although any one of these candidates will be virtually impossible to detect at the LHC, ...
0710.1668v2
2008-04-05
Analytic QCD - a short review
Analytic versions of QCD are those whose coupling alpha_s(Q^2) does not have the unphysical Landau singularities on the space-like axis (-q^2=Q^2 > 0). The coupling is analytic in the entire complex plane except the time-like axis (Q^2 < 0). Such couplings are thus suitable for application of perturbative methods down ...
0804.0872v2
2008-10-01
Magnetic Order Beyond RKKY in the Classical Kondo Lattice
We study the Kondo lattice model of band electrons coupled to classical spins, in three dimensions, using a combination of variational calculation and Monte Carlo. We use the weak coupling `RKKY' window and the strong coupling regime as benchmarks, but focus on the physically relevant intermediate coupling regime. Even...
0810.0140v2
2008-11-22
Synchronization of coupled demographic oscillators
Demographic oscillators are individual-based systems exhibiting temporal cycles sustained by the stochastic dynamics of the microscopic interacting particles. We here use the example of coupled predator-prey oscillators to show that synchronization to a common frequency can occur between two such systems, even if they ...
0811.3689v1
2009-03-06
Universality of the Nf=2 Running Coupling
We investigate universality of the Nf=2 running coupling in the Sch\"odinger functional scheme, by calculating the step scaling function in lattice QCD with the renorm alization group (RG) improved gauge action at both weak(u=0.9796) and strong(u=3.3340) couplings, where u=\bar{g}^2_SF with \bar{g}_SF being the running...
0903.1154v1
2009-03-20
Semi-passivity and synchronization of diffusively coupled neuronal oscillators
We discuss synchronization in networks of neuronal oscillators which are interconnected via diffusive coupling, i.e. linearly coupled via gap junctions. In particular, we present sufficient conditions for synchronization in these networks using the theory of semi-passive and passive systems. We show that the conductanc...
0903.3535v1
2009-03-26
Quantum Localization for Two Coupled Kicked Rotors
We study a system of two coupled kicked rotors, both classically and quantum mechanically, for a wide range of coupling parameters. This was motivated by two published reports, one of which reported quantum localization, while the other reported diffusion. The classical systems are chaotic, and exhibit normal diffusive...
0903.4632v2
2009-04-08
The exchange fluctuation theorem in quantum mechanics
We study the heat transfer between two finite quantum systems initially at different temperatures. We find that a recently proposed fluctuation theorem for heat exchange, namely the exchange fluctuation theorem [C. Jarzynski and D. K. Wojcik, Phys. Rev. Lett. 92, 230602 (2004)], does not generally hold in the presence ...
0904.1443v1
2009-04-15
Soliton Dynamics in Linearly Coupled Discrete Nonlinear Schrödinger Equations
We study soliton dynamics in a system of two linearly coupled discrete nonlinear Schr\"odinger equations, which describe the dynamics of a two-component Bose gas, coupled by an electromagnetic field, and confined in a strong optical lattice. When the nonlinear coupling strengths are equal, we use a unitary transformati...
0904.2415v1
2009-07-30
The strong-coupling limit of a Kondo spin coupled to a mesoscopic quantum dot: effective Hamiltonian in the presence of exchange correlations
We consider a Kondo spin that is coupled antiferromagnetically to a large chaotic quantum dot. Such a dot is described by the so-called universal Hamiltonian and its electrons are interacting via a ferromagnetic exchange interaction. We derive an effective Hamiltonian in the limit of strong Kondo coupling, where the sc...
0907.5297v1
2009-08-14
Probing scalar particle and unparticle couplings in e+ e- -> t tbar with transversely polarized beams
In searching for indications of new physics scalar particle and unparticle couplings in e^+ e^- \to t\bar t, we consider the role of transversely polarized initial beams at e^+ e^- colliders. By using a general relativistic spin density matrix formalism for describing the particles spin states, we find analytical expre...
0908.2027v2
2009-09-11
Couplings between dipole and quadrupole vibrations in tin isotopes
We study the couplings between collective vibrations such as the isovector giant dipole and isoscalar giant quadrupole resonances in tin isotopes in the framework of the time-dependent Hartree-Fock theory with a Skyrme energy density functional. These couplings are a source of anharmonicity in the multiphonon spectrum....
0909.2092v2
2009-09-13
Formation of Intermediate Coupling Optical Polarons and Bipolarons in Two-Dimensional Systems
he formation of the optical polaron and bipolaron in two-dimensional (2D) systems are studied in the intermediate electron-phonon coupling regime. The total energies of 2D polaron and bipolaron are calculated by using the Buimistrov-Pekar method of canonical transformations and analyzed in the weak, intermediate and st...
0909.2414v1
2009-09-15
Linear coupling of modes in 2D radially stratified astrophysical discs
We investigate mode coupling in a two dimensional compressible disc with radial stratification and differential rotation. We employ the global radial scaling of linear perturbations and study the linear modes in the local shearing sheet approximation. We employ a three-mode formalism and study the vorticity (W), entrop...
0909.2844v1
2009-11-01
Hierarchy of relevant couplings in perturbative renormalization group transformations
The phase diagram for the interacting fermions in weak coupling is described by the perturbative renormalization group equations. Due to the lack of analytic solutions for these coupled non-linear differential equations, it is rather subtle to tell which couplings are relevant or irrelevant. We propose a powerful class...
0911.0166v2
2009-11-23
Couplings in coupled channels versus wave functions: application to the X(3872) resonance
We perform an analytical study of the scattering matrix and bound states in problems with many physical coupled channels. We establish the relationship of the couplings of the states to the different channels, obtained from the residues of the scattering matrix at the poles, with the wave functions for the different ch...
0911.4407v2
2010-02-02
Generalized Rashba spin-orbit coupling for cold atoms
We study the possibility to generate a new type of spin-orbit coupling for the center of mass motion of cold atoms, using laser beams that resonantly couple N atomic internal ground states to an extra state. After a general analysis of the scheme, we concentrate on the tetrapod setup (N=4) where the atomic state can be...
1002.0578v2
2010-06-23
Motion of pole-dipole and quadrupole particles in non-minimally coupled theories of gravity
We study theories of gravity with non-minimal coupling between polarized media with pole-dipole and quadrupole moments and an arbitrary function of the space-time curvature scalar $R$ and the squares of the Ricci and Riemann curvature tensors. We obtain the general form of the equation of motion and show that an induce...
1006.4415v1
2010-06-28
Imaginary Cubic Perturbation: Numerical and Analytic Study
The analytic properties of the ground state resonance energy E(g) of the cubic potential are investigated as a function of the complex coupling parameter g. We explicitly show that it is possible to analytically continue E(g) by means of a resummed strong coupling expansion, to the second sheet of the Riemann surface, ...
1006.5303v2
2010-07-13
Dynamical evolution of a scalar field coupling to Einstein's tensor in the Reissner-Nordström black hole spacetime
We study the dynamical evolution of a scalar field coupling to Einstein's tensor in the background of Reissner-Nordstr\"{o}m black hole. Our results show that the the coupling constant $\eta$ imprints in the wave dynamics of a scalar perturbation. In the weak coupling, we find that with the increase of the coupling con...
1007.2019v2
2010-07-22
Equivalence condition for the canonical and microcanonical ensembles in coupled spin systems
It is typically assumed, without justification, that a weak coupling between a system and a bath is a necessary condition for the equivalence of a canonical ensemble and a microcanonical ensemble. For instance, in a canonical ensemble, temperature emerges if the system and the bath are uncoupled or weakly coupled. We i...
1007.3877v1
2010-07-22
Couplings in coupled channels versus wave functions in the case of resonances: application to the two $Λ(1405)$ states
In this paper we develop a formalism to evaluate wave functions in momentum and coordinate space for the resonant states dynamically generated in a unitary coupled channel approach. The on shell approach for the scattering matrix, commonly used, is also obtained in Quantum Mechanics with a separable potential, which al...
1007.3923v2
2010-07-26
Phase synchronization between collective rhythms of globally coupled oscillator groups: noisy identical case
We theoretically investigate collective phase synchronization between interacting groups of globally coupled noisy identical phase oscillators exhibiting macroscopic rhythms. Using the phase reduction method, we derive coupled collective phase equations describing the macroscopic rhythms of the groups from microscopic ...
1007.4382v1
2010-07-29
Phase synchronization between collective rhythms of globally coupled oscillator groups: noiseless non-identical case
Phase synchronization between collective oscillations exhibited by two weakly interacting groups of non-identical phase oscillators with internal and external global sinusoidal coupling of the groups is analyzed theoretically. Coupled amplitude equations describing the collective oscillations of the oscillator groups a...
1007.5161v1
2010-08-18
Superposition of Inductive and Capacitive Coupling in Superconducting LC Resonators
We present an experimental investigation of lumped-element superconducting LC resonators designed to provide different types of coupling to a transmission line. We have designed four resonator geometries including dipole and quadrupole configured inductors connected in parallel with low loss SiNx dielectric parallel-pl...
1008.3130v1
2010-08-19
Synchronization transitions in coupled time-delay electronic circuits with a threshold nonlinearity
Experimental observations of typical kinds of synchronization transitions are reported in unidirectionally coupled time-delay electronic circuits with a threshold nonlinearity and two time delays, namely feedback delay $\tau_1$ and coupling delay $\tau_2$. We have observed transitions from anticipatory to lag via compl...
1008.3300v1
2010-09-15
Deducing spectroscopic factors from wave-function asymptotics
In a coupled-channel model, we explore the effects of coupling between configurations on the radial behavior of the wave function and, in particular, on the spectroscopic factor (SF) and the asymptotic normalization coefficient (ANC). We evaluate the extraction of a SF from the ratio of the ANC of the coupled-channel m...
1009.2878v3
2010-10-04
Consistent Energy-Based Atomistic/Continuum Coupling for Two-Body Potentials in One and Two Dimensions
This paper addresses the problem of consistent energy-based coupling of atomistic and continuum models of materials, limited to zero-temperature statics of simple crystals. It has been widely recognized that the most practical coupled methods exhibit large errors on the atomistic/continuum interface (which are often at...
1010.0512v3
2010-10-27
Cosmology of Chameleons with Power-Law Couplings
In chameleon field theories a scalar field can couple to matter with gravitational strength and still evade local gravity constraints due to a combination of self-interactions and the couplings to matter. Originally, these theories were proposed with a constant coupling to matter, however, the chameleon mechanism also ...
1010.5650v2
2010-11-13
Crowd synchrony and quorum sensing in delay-coupled lasers
Crowd synchrony and quorum sensing arise when a large number of dynamical elements communicate with each other via a common information pool. Previous evidence in different fields, including chemistry, biology and civil engineering, has shown that this type of coupling leads to synchronization, when coupling is instant...
1011.3155v2
2010-11-26
Coupling slot-waveguide cavities for large-scale quantum optical devices
By offering effective modal volumes significantly less than a cubic wavelength, slot-waveguide cavities offer a new in-road into strong atom-photon coupling in the visible regime. Here we explore two-dimensional arrays of coupled slot cavities which underpin designs for novel quantum emulators and polaritonic quantum p...
1011.5690v1
2010-11-29
Quantum dynamics of a dc-SQUID coupled to an asymmetric Cooper pair transistor
We present a theoretical analysis of the quantum dynamics of a superconducting circuit based on a highly asymmetric Cooper pair transistor (ACPT) in parallel to a dc-SQUID. Starting from the full Hamiltonian we show that the circuit can be modeled as a charge qubit (ACPT) coupled to an anharmonic oscillator (dc-SQUID)....
1011.6148v1
2011-01-04
Search for W'->tb resonances with left- and right-handed couplings to fermions
We present a search for the production of a heavy gauge boson, W', that decays to third-generation quarks, by the D0 Collaboration in ppbar collisions at sqrt(s)= 1.96 TeV. We set 95% confidence level upper limits on the production cross section times branching fraction. For the first time, we set limits for arbitrary ...
1101.0806v2
2011-01-25
Quantum phase transitions for two coupled sites with dipole-coupled effective Jaynes-Cummings model
The nature of the ground states for a system composed of two coupled cavities with each containing a pair of dipole-coupled two-level atoms are studied over a wide range of detunings and dipole coupling strengths. The cases for three limits of exact resonance, large positive and negative detunings are discussed, and fo...
1101.4751v2
2011-01-25
Quantum transport of double quantum dots coupled to an oscillator in arbitrary strong coupling regime
In this paper, we investigate the quantum transport of a double quantum dot coupled with a nanomechanical resonator at arbitrary strong electron-phonon coupling regimes. We employ the generalized quantum master equation to study full counting statistics of currents. We demonstrate the coherent phonon states method can ...
1101.4864v2
2011-01-27
Next-to-leading order QCD corrections to the top quark associated with $γ$ production via model-independent flavor-changing neutral-current couplings at hadron colliders
We present the complete next-to-leading order (NLO) QCD corrections to the top quark associated with $\gamma$ production induced by model-independent $tq\gamma$ and $tqg$ flavor-changing neutral-current (FCNC) couplings at hadron colliders, respectively. We also consider the mixing effects between the $tq\gamma$ and $t...
1101.5346v1
2011-02-07
Impact of spin-orbit coupling on the Holstein polaron
We utilize an exact variational numerical procedure to calculate the ground state properties of a polaron in the presence of a Rashba-like spin orbit interaction. Our results corroborate with previous work performed with the Momentum Average approximation and with weak coupling perturbation theory. We find that spin or...
1102.1421v1
2011-02-14
Spatially Coupled Codes over the Multiple Access Channel
We consider spatially coupled code ensembles over a multiple access channel. Convolutional LDPC ensembles are one instance of spatially coupled codes. It was shown recently that, for transmission over the binary erasure channel, this coupling of individual code ensembles has the effect of increasing the belief propagat...
1102.2856v1
2011-02-22
Spatially-Coupled MacKay-Neal Codes and Hsu-Anastasopoulos Codes
Kudekar et al. recently proved that for transmission over the binary erasure channel (BEC), spatial coupling of LDPC codes increases the BP threshold of the coupled ensemble to the MAP threshold of the underlying LDPC codes. One major drawback of the capacity-achieving spatially-coupled LDPC codes is that one needs to ...
1102.4612v3
2011-03-31
Resonant energy transfer enhanced by off-diagonal exciton-phonon coupling
Dynamics of resonant energy transfer of a single excitation in a molecular dimer system is studied in the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. It is found that the off-diagonal coupling plays an important role in the excitation energy transfer process. Coherent transfer can be fou...
1103.6162v2
2011-06-17
Entanglement spectra of coupled S=1/2 spin chains in a ladder geometry
We study the entanglement spectrum of spin-1/2 XXZ ladders both analytically and numerically. Our analytical approach is based on perturbation theory starting either from the limit of strong rung coupling, or from the opposite case of dominant coupling along the legs. In the former case we find to leading order that th...
1106.3419v2
2011-09-02
Half-turn symmetric FPLs with rare couplings and tilings of hexagons
In this work, we put to light a formula that relies the number of fully packed loop configurations (FPLs) associated to a given coupling pi to the number of half-turn symmetric FPLs (HTFPLs) of even size whose coupling is a punctured version of the coupling pi. When the coupling pi is the coupling with all arches paral...
1109.0366v1
2011-10-05
Molecule Induced Strong Exchange Coupling between Ferromagnetic Electrodes of a Magnetic Tunnel Junction
Multilayer edge molecular spintronics device (MEMSD) approach can produce novel logic and memory units for the computers. MEMSD are produced by bridging the molecular channels across the insulator, in the exposed edge region(s) of a magnetic tunnel junction (MTJ). The bridged molecular channels start serving as the dom...
1110.0885v1
2011-10-24
Oscillatory coupling between a monolithic whispering-gallery resonator and a buried bus waveguide
We report on a combined theoretical and experimental study of the optical coupling between a microdisk resonator and a waveguide laying on different planes. While the lateral coupling between a planar resonator and a waveguide is characterized by a unique distance at which the resonant waveguide transmission vanishes b...
1110.5211v1
2011-10-31
Spin-Orbit Coupled Quantum Gases
In this review we will discuss the experimental and theoretical progresses in studying spin-orbit coupled degenerate atomic gases during the last two years. We shall first review a series of pioneering experiments in generating synthetic gauge potentials and spin-orbit coupling in atomic gases by engineering atom-light...
1110.6798v1
2011-12-20
Transition from spatial coherence to incoherence in coupled chaotic systems
We investigate the spatio-temporal dynamics of coupled chaotic systems with nonlocal interactions, where each element is coupled to its nearest neighbors within a finite range. Depending upon the coupling strength and coupling radius, we find characteristic spatial patterns such as wave-like profiles and study the tran...
1112.4869v2
2012-03-06
Short-range correlations in dilute atomic Fermi gases with spin-orbit coupling
We study the short-range correlation strength of three dimensional spin half dilute atomic Fermi gases with spin-orbit coupling. The interatomic interaction is modeled by the contact pseudopotential. In the high temperature limit, we derive the expression for the second order virial expansion of the thermodynamic poten...
1203.1159v1
2012-06-01
Coupling techniques for nonlinear hyperbolic equations. IV. Multi-component coupling and multidimensional well-balanced schemes
This series of papers is devoted to the formulation and the approximation of coupling problems for nonlinear hyperbolic equations. The coupling across an interface in the physical space is formulated in term of an augmented system of partial differential equations. In an earlier work, this strategy allowed us to develo...
1206.0248v1
2012-06-04
Microcavity controlled coupling of excitonic qubits
Controlled non-local energy and coherence transfer enables light harvesting in photosynthesis and non-local logical operations in quantum computing. The most relevant mechanism of coherent coupling of distant qubits is coupling via the electromagnetic field. Here, we demonstrate the controlled coherent coupling of spat...
1206.0592v1
2012-07-04
Superpotential de-sequestering in string models
Non-perturbative superpotential cross-couplings between visible sector matter and K\"ahler moduli can lead to significant flavour-changing neutral currents in compactifications of type IIB string theory. Here, we compute corrections to Yukawa couplings in orbifold models with chiral matter localised on D3-branes and no...
1207.1103v1
2012-07-10
Half--Hypers and Quivers
We study systematically the BPS spectra of N=2 SYM coupled to half--hypermultiplets, the basic example being E_7 SYM coupled to a half--hyper in the 56 irrepr. In order to do this, we determine the BPS quivers with superpotential of such N=2 models using a new technique we introduce. The computation of the BPS spectra ...
1207.2275v1
2012-07-25
High cooperativity in coupled microwave resonator ferrimagnetic insulator hybrids
We report the observation of strong coupling between the exchange-coupled spins in gallium-doped yttrium iron garnet and a superconducting coplanar microwave resonator made from Nb. The measured coupling rate of 450 MHz is proportional to the square-root of the number of exchange-coupled spins and well exceeds the loss...
1207.6039v2
2012-08-28
Spin-orbit coupled particle in a spin bath
We consider a spin-orbit coupled particle confined in a quantum dot in a bath of impurity spins. We investigate the consequences of spin-orbit coupling on the interactions that the particle mediates in the spin bath. We show that in the presence of spin-orbit coupling, the impurity-impurity interactions are no longer s...
1208.5606v1
2012-08-29
Modified Bethe-Peierls boundary condition for ultracold atoms with Spin-Orbit coupling
We show that the Bethe-Peierls (BP) boundary condition should be modified for ultracold atoms with spin-orbit (SO) coupling. Moreover, we derive a general form of the modified BP boundary condition, which is applicable to a system with arbitrary kind of SO coupling. In the modified BP condition, an anisotropic term app...
1208.5976v4
2012-09-22
Heat flow in InAs/InP heterostructure nanowires
The transfer of heat between electrons and phonons plays a key role for thermal management in future nanowire-based devices, but only a few experimental measurements of electron-phonon (e-ph) coupling in nanowires are available. Here, we combine experimental temperature measurements on an InAs/InP heterostructure nanow...
1209.4940v1
2012-10-16
Baryon asymmetry and dark matter from soft leptogenesis
The framework for soft leptogenesis minimally extended with a DM sector is studied. A heavy singlet neutrino superfield acts as the source for (s)lepton asymmetry and by coupling to the singlet DM superfield it produces a DM particle density through decays. The nature of DM generated is twofold depending on whether the...
1210.4335v3