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1999-11-30
Coupling of vector fields at high energies
In general relativity and electrodynamics fields are always generated from static monopoles (like mass or electric charge) or their corresponding currents by surrounding them in a spherical configuration. We investigate a generation of fields from primary fields by a scalar coupling. The generated secondary fields fulf...
9911250v3
1999-12-21
Scalar Quartic Couplings in Type IIB Supergravity on $AdS_5\times S^5$
All quartic couplings of scalar fields $s^I$ that are dual to extended chiral primary operators in ${\cal N}=4$ SYM$_4$ are derived by using the covariant equations of motion for type IIB supergravity on $AdS_5\times S^5$. It is shown that despite some expectations if one keeps the structure of the cubic terms untouche...
9912210v4
2000-09-08
Singular Phases of Seiberg-Witten Integrable Systems: Weak and Strong Coupling
We consider the singular phases of the smooth finite-gap integrable systems arising in the context of Seiberg-Witten theory. These degenerate limits correspond to the weak and strong coupling regimes of SUSY gauge theories. The spectral curves in such limits acquire simpler forms: in most cases they become rational, an...
0009060v2
2001-01-17
Two-Point Stress-Tensor Correlator in N=1 SYM(2+1)
Recent advances in string theory have highlighted the need for reliable numerical methods to calculate correlators at strong coupling in supersymmetric theories. We present a calculation of the correlator <0|T^{++}(r)T^{++}(0)|0> in N=1 SYM theory in 2+1 dimensions. The numerical method we use is supersymmetric discret...
0101120v1
2001-04-17
Ramond-Ramond Couplings of Noncommutative D-branes
We propose the leading couplings, in an alpha' expansion, of noncommutative D-branes to RR potentials in a constant NSNS B-field for an arbitrary choice of noncommutative parameter. The proposal is motivated by some string amplitude computations. The zero momentum couplings are topological in nature and involve Elliott...
0104139v2
2002-05-30
Couplings in Pseudo-Supersymmetry
We analyze theories in which a supersymmetric sector is coupled to a supersymmetry-breaking sector described by a non-linear realization. We show how to consistently couple N=1 supersymmetric matter to non-supersymmetric matter in such a way that all interactions are invariant under non-linear supersymmetry transformat...
0205300v3
2002-11-11
Non-renormalization theorems from extension to local coupling
The extension of coupling constants to space-time dependent fields, the local couplings, makes possible to derive the non-renormalization theorems of supersymmetry by an algebraic characterization of Lagrangian N=1 supermultiplets. For super-Yang-Mills theories the construction implies non-renormalization of the coupli...
0211085v1
2003-01-20
Yukawa couplings in SO(10) heterotic M-theory vacua
We demonstrate the existence of a class of N=1 supersymmetric nonperturbative vacua of Horava-Witten M-theory compactified on a torus fibered Calabi-Yau 3-fold Z with first homotopy group \pi_{1}(Z)= Z2, having the following properties: 1) SO(10) grand unification group, 2) net number of three generations of chiral fer...
0301147v1
2003-08-28
N=1 Worldsheet Boundary Couplings and Covariance of non-Abelian Worldvolume Theory
A systematic construction is given for N=1 open string boundary coupling to Abelian and non-Abelian Dp-brane worldvolume fields, in general curved backgrounds. The basic ingredient is a set of four ``boundary vectors'' that provide a unified description of boundary conditions and boundary couplings. We then turn to the...
0308201v1
2003-10-03
Spin-Spin and Spin-Orbit Interactions in Strongly Coupled Gauge Theories
We evaluate the spin-orbit and spin-spin interaction between two fermions in strongly coupled gauge theories in their Coulomb phase. We use the quasi-instantaneous character of Coulomb's law at strong coupling to resum a class of ladder diagrams. For ${\cal N}=4$ SYM we derive both weak and strong coupling limits of th...
0310031v1
2003-10-18
Coupling the Supersymmetric 210 Vector Multiplet to Matter in SO(10)
An analysis of the couplings of the 210 dimensional SO(10) vector multiplet to matter is given. Specifically we give an $SU(5)\times U(1)$ decomposition of the vector couplings $\bar{16}_{\pm}-16_{\pm}-210$, where $16_{\pm}$ is the semispinor of SO(10) chirality ${\pm}$, using a recently derived basic theorem. The anal...
0310178v1
2003-11-30
One-loop Gauge Couplings in Orbifold Field Theories
We discuss the gauge coupling renormalization in orbifold field theories in which the 4-dimensional graviton and/or matter fields are quasi-localized in extra dimension to generate hierarchically different mass scales and/or Yukawa couplings. In such theories, there can be large calculable Kaluza-Klein threshold correc...
0312006v2
2004-01-13
Casimir Energies and Pressures for $δ$-function Potentials
The Casimir energies and pressures for a massless scalar field associated with $\delta$-function potentials in 1+1 and 3+1 dimensions are calculated. For parallel plane surfaces, the results are finite, coincide with the pressures associated with Dirichlet planes in the limit of strong coupling, and for weak coupling d...
0401090v1
2004-04-02
N=4 central charge superspace at work for supergravity coupled to an arbitrary number of abelian vector multiplets
We present the description in central charge superspace of N=4 supergravity with antisymmetric tensor coupled to an arbitrary number of abelian vector multiplets. All the gauge vectors of the coupled system are treated on the same footing as gauge fields corresponding to translations along additional bosonic coordinate...
0404019v1
2004-04-27
Stochastic formulation of the renormalization group: supersymmetric structure and topology of the space of couplings
The exact or Wilson renormalization group equations can be formulated as a functional Fokker-Planck equation in the infinite-dimensional configuration space of a field theory, suggesting a stochastic process in the space of couplings. Indeed, the ordinary renormalization group differential equations can be supplemented...
0404212v1
2004-05-22
The static potential in QED$_3$ with non-minimal coupling
Here we study the effect of the non-minimal coupling $j^{\mu}\eps \partial^{\nu} A^{\alpha} $ on the static potential in multiflavor QED$_3$. Both cases of four and two components fermions are studied separately at leading order in the $1/N $ expansion. Although a non-local Chern-Simons term appears, in the four compon...
0405196v1
2004-06-14
Yukawa Coupling Structure in Intersecting D-brane Models
The structure of Yukawa coupling matrices is investigated in type IIA T^6/(Z_2 x Z_2) orientifold models with intersecting D-branes. Yukawa coupling matrices are difficult to be realistic in the conventional models in which the generation structure emerges by the multiple intersection of D-branes in the factorized T^6 ...
0406115v3
2005-02-03
N=1 RG Flows, Product Groups, and a-Maximization
We explore new IR phenomena and dualities, arising for product groups, in the context of N=1 supersymmetric gauge theories. The RG running of the multiple couplings can radically affect each other. For example, an otherwise IR interacting coupling can be driven to be instead IR free by an arbitrarily small, but non-zer...
0502049v1
2005-02-23
Space-time dependent couplings in N=1 SUSY gauge theories: Anomalies and Central Functions
We consider N=1 supersymmetric gauge theories in which the couplings are allowed to be space-time dependent functions. Both the gauge and the superpotential couplings become chiral superfields. As has recently been shown, a new topological anomaly appears in models with space-time dependent gauge coupling. Here we show...
0502214v1
2005-03-16
Infinite reduction of couplings in non-renormalizable quantum field theory
I study the problem of renormalizing a non-renormalizable theory with a reduced, eventually finite, set of independent couplings. The idea is to look for special relations that express the coefficients of the irrelevant terms as unique functions of a reduced set of independent couplings lambda, such that the divergence...
0503131v2
2005-03-21
Renormalization of Supersymmetric Gauge Theories on Orbifolds: Brane Gauge Couplings and Higher Derivative Operators
We consider supersymmetric gauge theories coupled to hyper multiplets on five and six dimensional orbifolds and determine the bulk and local fixed point renormalizations of the gauge couplings. We infer from a component analysis that the hyper multiplet does not induce renormalization of the brane gauge couplings on th...
0503153v1
2005-04-11
A transition in the spectrum of the topological sector of $φ_2^4$ theory at strong coupling
We investigate the strong coupling region of the topological sector of the two-dimensional $\phi^4$ theory. Using discrete light cone quantization (DLCQ), we extract the masses of the lowest few excitations and observe level crossings. To understand this phenomena, we evaluate the expectation value of the integral of t...
0504094v1
2005-07-01
Energy conditions for a generally coupled scalar field outside a reflecting sphere
We calculate the stress-energy tensor for a scalar field with general curvature coupling, outside a perfectly reflecting sphere with Dirichlet boundary conditions. For conformal coupling we find that the null energy condition is always obeyed, and therefore the averaged null energy condition (ANEC) is also obeyed. Sinc...
0507013v3
2005-07-26
Quantum Gravity, Torsion, Parity Violation and all that
We discuss the issue of parity violation in quantum gravity. In particular, we study the coupling of fermionic degrees of freedom in the presence of torsion and the physical meaning of the Immirzi parameter from the viewpoint of effective field theory. We derive the low-energy effective lagrangian which turns out to in...
0507253v2
2005-10-06
Casimir energy and a cosmological bounce
We review different computation methods for the renormalised energy momentum tensor of a quantised scalar field in an Einstein Static Universe. For the extensively studied conformally coupled case we check their equivalence; for different couplings we discuss violation of different energy conditions. In particular, the...
0510052v1
2005-10-17
Noncommutative geometry, Quantum effects and DBI-scaling in the collapse of D0-D2 bound states
We study fluctuations of time-dependent fuzzy two-sphere solutions of the non-abelian DBI action of D0-branes, describing a bound state of a spherical D2-brane with N D0-branes. The quadratic action for small fluctuations is shown to be identical to that obtained from the dual abelian D2-brane DBI action, using the non...
0510144v2
2005-10-23
Time variation of the gravitational coupling constant in all dimensions: Kasner-type cosmological models
We formulate the time variation of the gravitational coupling constant in all dimensions. We show that the time variation of the gravitational coupling constant is related to the time variation of the Newton's constant in three-space dimensions and also is related to the time variation of the volume of the extra spatia...
0510197v4
2006-02-10
Tri-linear Couplings in an Heterotic Minimal Supersymmetric Standard Model
We calculate, at the classical level, the superpotential tri-linear couplings of the only known globally consistent heterotic minimal supersymmetric Standard Model [ hep-th/0512149 ]. This recently constructed model is based on a compactification of the E_8 x E_8 heterotic string theory on a Calabi-Yau threefold with Z...
0602096v2
2006-05-20
Renormalization and causality violations in classical gravity coupled with quantum matter
I prove that classical gravity coupled with quantized matter can be renormalized with a finite number of independent couplings, plus field redefinitions, without introducing higher-derivative kinetic terms in the gravitational sector, but adding vertices that couple the matter stress-tensor with the Ricci tensor. The t...
0605205v2
2006-06-01
Anomaly Cancellation in Supergravity with Fayet-Iliopoulos Couplings
We review and clarify the cancellation conditions for gauge anomalies which occur when N=1, D=4 supergravity is coupled to a Kahler non-linear sigma-model with gauged isometries and Fayet-Iliopoulos couplings. For a flat sigma-model target space and vanishing Fayet-Iliopoulos couplings, consistency requires just the co...
0606012v1
2006-06-29
Conformal symmetry of gravity and the cosmological constant problem
In absence of matter Einstein gravity with a cosmological constant $\La$ can be formulated as a scale-free theory depending only on the dimensionless coupling constant G \Lambda where G is Newton constant. We derive the conformal field theory (CFT) and its improved stress-energy tensor that describe the dynamics of con...
0606274v2
2006-07-11
Numerical study of curvature perturbations in a brane-world inflation at high-energies
We study the evolution of scalar curvature perturbations in a brane-world inflation model in a 5D Anti-de Sitter spacetime. The inflaton perturbations are confined to a 4D brane but they are coupled to the 5D bulk metric perturbations. We numerically solve full coupled equations for the inflaton perturbations and the 5...
0607068v2
2006-08-22
The Gross-Neveu Model from String Theory
We study an intersecting D-brane model which at low energies describes (1+1)-dimensional chiral fermions localized at defects on a stack of N_c D4-branes. Fermions at different defects interact via exchange of massless (4+1)-dimensional fields. At weak coupling this interaction gives rise to the Gross-Neveu (GN) model ...
0608149v1
2006-11-11
Renormalizable acausal theories of classical gravity coupled with interacting quantum fields
We prove the renormalizability of various theories of classical gravity coupled with interacting quantum fields. The models contain vertices with dimensionality greater than four, a finite number of matter operators and a finite or reduced number of independent couplings. An interesting class of models is obtained from...
0611131v2
2006-12-19
Meson coupling constants at high mass and large N_c
Quark-hadron duality implies that a process described in terms of quark loops should be the hadronic amplitude when averaged over a sufficient number of states. Ambiguities associated with the notion of quark hadron duality can be made arbitrarily small for highly excited mesons at large $N_c$. QCD is expected to form ...
0612209v2
2007-01-17
Dependence of SU(N) coupling behavior on the size of extra dimensions
Coupling constants at high energy scales are studied in SU(N) gauge theory with distinct sizes of extra dimensions. We present the solution of gauge couplings as functions of the energy in such a way as to track the number of Kaluza-Klein modes. In a flat extra dimension, it is shown that the gauge couplings have logar...
0701159v2
1999-10-09
How to Couple from the Past Using a Read-Once Source of Randomness
We give a new method for generating perfectly random samples from the stationary distribution of a Markov chain. The method is related to coupling from the past (CFTP), but only runs the Markov chain forwards in time, and never restarts it at previous times in the past. The method is also related to an idea known as PA...
9910050v1
2000-08-22
Coupling Tensors and Poisson Geometry Near a Single Symplectic Leaf
In the framework of the connection theory, a contravariant analog of the Sternberg coupling procedure is developed for studying a natural class of Poisson structures on fiber bundles, called coupling tensors. We show that every Poisson structure near a closed symplectic leaf can be realized as a coupling tensor. Our ma...
0008162v3
2004-12-16
Foliation-coupling Dirac structures
We extend the notion of "coupling with a foliation" from Poisson to Dirac structures and get the corresponding generalization of the Vorobiev characterization of coupling Poisson structures. We show that any Dirac structure is coupling with the fibers of a tubular neighborhood of an embedded presymplectic leaf, give ne...
0412318v3
2005-11-08
Metric Construction, Stopping Times and Path Coupling
In this paper we examine the importance of the choice of metric in path coupling, and the relationship of this to \emph{stopping time analysis}. We give strong evidence that stopping time analysis is no more powerful than standard path coupling. In particular, we prove a stronger theorem for path coupling with stopping...
0511202v2
2002-02-01
One non-relativistic particle coupled to a photon field
We investigate the ground state energy of an electron coupled to a photon field. First, we regard the self-energy of a free electron, which we describe by the Pauli-Fierz Hamiltonian. We show that, in the case of small values of the coupling constant $\alpha$, the leading order term is represented by $2\pi^{-1} \alpha ...
0202001v3
2002-09-25
Exotic Yang-Mills dilaton gauge theories
A exotic class of nonlinear p-form nonabelian gauge theories is studied, arising from the most general allowed nontrivial deformation of linear abelian gauge theory for a set of massless 1-form fields and 2-form fields in four dimensions. These theories combine a Chapline-Manton type coupling of the 1-forms and 2-forms...
0209052v4
2004-11-29
Precise coupling terms in adiabatic quantum evolution: The generic case
For multi-level time-dependent quantum systems one can construct superadiabatic representations in which the coupling between separated levels is exponentially small in the adiabatic limit. Based on results from [BeTe1] for special Hamiltonians we explicitly determine the asymptotic behavior of the exponentially small ...
0411083v1
2005-11-06
Open Subsystems of Conservative Systems
The subject under study is an open subsystem of a larger linear and conservative system and the way in which it is coupled to the rest of system. Examples are a model of crystalline solid as a lattice of coupled oscillators with a finite piece constituting the subsystem, and an open system such as the Helmholtz resonat...
0511023v2
2000-04-10
Exact solutions and dynamics of globally coupled phase oscillators
We analyze mean-field models of synchronization of phase oscillators with singular couplings and subject to external random forces. They are related to the Kuramoto-Sakaguchi model. Their probability densities satisfy local partial differential equations similar to the Porous Medium, Burgers and extended Burgers equati...
0004016v1
2001-04-25
Anticipated synchronization in coupled chaotic maps with delays
We study the synchronization of two chaotic maps with unidirectional (master-slave) coupling. Both maps have an intrinsic delay $n_1$, and coupling acts with a delay $n_2$. Depending on the sign of the difference $n_1-n_2$, the slave map can synchronize to a future or a past state of the master system. The stability pr...
0104061v1
2001-07-30
Periodicity Manifestations in the Non-Locally Coupled Maps
We study how periodicity manifestations recently found in the turbulent globall coupled maps depend on the global feature of the couplings. We examine three non-locally coupled map models. In the first two, the all-to-all interaction is maintained but the coupling decreases with distance in a power and an exponential l...
0107068v3
2001-10-23
Plasticity and learning in a network of coupled phase oscillators
A generalized Kuramoto model of coupled phase oscillators with slowly varying coupling matrix is studied. The dynamics of the coupling coefficients is driven by the phase difference of pairs of oscillators in such a way that the coupling strengthens for synchronized oscillators and weakens for non-synchronized pairs. T...
0110044v1
2002-03-19
From Coupled Dynamical Systems to Biological Irreversibility
In the first half of the paper, some recent advances in coupled dynamical systems, in particular, a globally coupled map are surveyed. First, dominance of Milnor attractors in partially ordered phase is demonstrated. Second, chaotic itinerancy in high-dimensional dynamical systems is briefly reviewed, with discussion o...
0203040v1
2002-12-17
Delay-induced Synchronization Phenomena in an Array of Globally Coupled Logistic Maps
We study the synchronization of a linear array of globally coupled identical logistic maps. We consider a time-delayed coupling that takes into account the finite velocity of propagation of the interactions. We find globally synchronized states in which the elements of the array evolve along a periodic orbit of the unc...
0212037v2
2003-09-19
Rotating Spiral Waves with Phase-Randomized Core in Non-locally Coupled Oscillators
Rotating spiral waves with a central core composed of phase-randomized oscillators can arise in reaction-diffusion systems if some of the chemical components involved are diffusion-free. This peculiar phenomenon is demonstrated for a paradigmatic three-component reaction-diffusion model. The origin of this anomalous sp...
0309052v1
2005-04-23
Chimera States in a Ring of Nonlocally Coupled Oscillators
Arrays of identical limit-cycle oscillators have been used to model a wide variety of pattern-forming systems, such as neural networks, convecting fluids, laser arrays, and coupled biochemical oscillators. These systems are known to exhibit rich collective behavior, from synchrony and traveling waves to spatiotemporal ...
0504046v2
2006-03-29
Scaling behaviour of non-hyperbolic coupled map lattices
Coupled map lattices of non-hyperbolic local maps arise naturally in many physical situations described by discretised reaction diffusion equations or discretised scalar field theories. As a prototype for these types of lattice dynamical systems we study diffusively coupled Tchebyscheff maps of N-th order which exhibit...
0603067v2
2006-07-11
Synchronization by dynamical relaying in electronic circuit arrays
We experimentally study the synchronization of two chaotic electronic circuits whose dynamics is relayed by a third parameter-matched circuit, to which they are coupled bidirectionally in a linear chain configuration. In a wide range of operating parameters, this setup leads to synchronization between the outer circuit...
0607018v1
2006-09-30
Generalized Chaotic Synchronizationin Coupled Ginzburg-Landau Equations
Generalized synchronization is analyzed in unidirectionally coupled oscillatory systems exhibiting spatiotemporal chaotic behavior described by Ginzburg-Landau equations. Several types of coupling betweenthe systems are analyzed. The largest spatial Lyapunov exponent is proposed as a new characteristic of the state of ...
0610001v1
2006-12-06
State Differentiation by Transient Truncation in Coupled Threshold Dynamics
Dynamics with a threshold input--output relation commonly exist in gene, signal-transduction, and neural networks. Coupled dynamical systems of such threshold elements are investigated, in an effort to find differentiation of elements induced by the interaction. Through global diffusive coupling, novel states are found...
0612013v1
2006-12-23
Synchronized dynamics of cortical neurons with time-delay feedback
The dynamics of three mutually coupled cortical neurons with time delays in the coupling are explored numerically and analytically. The neurons are coupled in a line, with the middle neuron sending a somewhat stronger projection to the outer neurons than the feedback it receives, to model for instance the relay of a si...
0612053v1
2007-01-12
Amplification in the auditory periphery: the effect of coupling tuning mechanisms
A mathematical model describing the coupling between two independent amplification mechanisms in auditory hair cells is proposed and analyzed. Hair cells are cells in the inner ear responsible for translating sound-induced mechanical stimuli into an electrical signal that can then be recorded by the auditory nerve. In ...
0701022v1
1993-11-11
Constraints on the $πNN$ Coupling Constant from the $NN$ System
The sensitivity of the deuteron and of $pp$ scattering to the $\pi NN$ and $\rho NN$ coupling constants is investigated systematically. We find that the deuteron can be described about equally well with either {\it large $\pi$ and $\rho$} or {\it small $\pi$ and $\rho$} coupling constants. However, $pp$ scattering clea...
9311012v1
1996-08-08
Derivation and assessment of strong coupling core-particle model from the Kerman-Klein-Dönau-Frauendorf theory
We review briefly the fundamental equations of a semi-microscopic core-particle coupling method that makes no reference to an intrinsic system of coordinates. We then demonstrate how an intrinsic system can be introduced in the strong coupling limit so as to yield a completely equivalent formulation. It is emphasized t...
9608011v1
1997-06-23
Isospin Splitting in the Pion-Nucleon Couplings from QCD Sum Rules
We use QCD sum rules for the three point function of a pseudoscalar and two nucleonic currents in order to estimate the charge dependence of the pion nucleon coupling constant coming from isospin violation in the strong interaction. The effect can be attributed primarily to the difference of the quark condensates <ubar...
9706056v1
1998-02-19
A new Perspective on the Scalar meson Puzzle, from Spontaneous Chiral Symmetry Breaking Beyond BCS
We introduce coupled channels of Bethe-Salpeter mesons both in the boundstate equation for mesons and in the mass gap equation for chiral symmetry. Consistency is insured by the Ward Identities for axial currents, which preserve the Goldstone boson nature of the pion and prevents a systematic shift of the hadron spectr...
9802058v2
1999-06-08
Chiral Unitary Approach To The N*N*pi, N*N*eta Couplings For The N*(1535) Resonance
Using a chiral unitary model in which the negative parity nucleon resonance $N^\ast \equiv N^\ast(1535)$ is generated dynamically by means of the Bethe Salpeter equation with coupled meson baryon channels in the $S = 0$ sector, we have obtained the $\pi^0 N^\ast N^\ast$ and $\eta N^\ast N^\ast$ couplings. The $\pi^0 N^...
9906018v2
1999-08-03
Role of break-up processes in fusion enhancement of drip-line nuclei at energies below the Coulomb barrier
We carry out realistic coupled-channels calculations for $^{11}$Be + $^{208}$Pb reaction in order to discuss the effects of break-up of the projectile nucleus on sub-barrier fusion. We discretize in energy the particle continuum states, which are associated with the break-up process, and construct the coupling form...
9908012v1
2000-05-17
Nucleon Resonance Transition Couplings to Vector Mesons
Recent heavy ion experiments indicate modifications of the $\rho-$meson mass in medium. In the CERES experiments $\rho-$mesons are produced at $\sim$ normal nuclear matter density, where hadrons are more appropriate constituents than quarks. A collective "nuclear $\rho$", in which every nucleon is excited to the N(1520...
0005049v1
2000-09-29
Quark-Meson Coupling Model for a Nucleon
The quark-meson coupling model for a nucleon is considered. The model describes a nucleon as an MIT bag, in which quarks are coupled to scalar and vector mesons. A set of coupled equations for the quark and the meson fields are obtained and are solved in a self-consistent way. It is shown that the mass of a nucleon as ...
0009089v1
2000-10-20
Quark-meson coupling model for a nucleon
We considered the quark-meson coupling model for a nucleon. The model describes a nucleon as an MIT bag, in which quarks are coupled to the scalar and the vector mesons. A set of coupled equations for the quark and the meson fields are obtained and are solved in a self-consistent manner. We show that the mass of a dres...
0010067v1
2002-02-08
Fusion of light exotic nuclei at near-barrier energies : effect of inelastic excitation
The effect of inelastic excitation of exotic light projectiles (proton- as well as neutron-rich) $^{17}$F and $^{11}$Be on fusion with heavy target has been studied at near-barrier energies. The calculations have been performed in the coupled channels approach where, in addition to the normal coupling of the ground sta...
0202027v1
2002-02-08
Fusion of light proton-rich exotic nuclei at near-barrier energies
We study theoretically fusion of the light proton-rich exotic nuclei $^{17}$F and $^8$B at near-barrier energies in order to investigate the possible role of breakup processes on their fusion cross sections. To this end, coupled channel calculations are performed considering the couplings to the breakup channels of the...
0202028v1
2002-06-18
Induced pseudoscalar coupling of the proton weak interaction
The induced pseudoscalar coupling $g_p$ is the least well known of the weak coupling constants of the proton's charged--current interaction. Its size is dictated by chiral symmetry arguments, and its measurement represents an important test of quantum chromodynamics at low energies. During the past decade a large body ...
0206039v1
2002-09-27
Lambda Lambda-XiN Coupling Effects in Light Hypernuclei
The significance of $\Lambda\Lambda$-$\Xi$N coupling in double-$\Lambda$ hypernuclei has been studied. The Pauli suppression effect due to this coupling in $^6_{\Lambda\Lambda}$He has been found to be 0.43 MeV for the coupling strength of the NSC97e potential. This indicates that the free-space $\Lambda\Lambda$ interac...
0209090v1
2002-10-31
Relativistic Mean Field Model with Generalized Derivative Nucleon-Meson Couplings
The quantum hadrodynamics (QHD) model with minimal nucleon-meson couplings is generalized by introducing couplings of mesons to derivatives of the nucleon field in the Lagrangian density. This approach allows an effective description of a state-dependent in-medium interaction in the mean-field approximation. Various pa...
0210090v1
2003-11-24
Hyperonic mixing in five-baryon double-strangeness hypernuclei in a two-channel treatment
Properties of hypernuclei $_{\Lambda \Lambda}^5$H and $_{\Lambda \Lambda }^5$He are studied in a two-channel approach with explicit treatment of coupling of channels ^3\text{Z}+\Lambda+\Lambda and \alpha+\Xi. Diagonal \Lambda\Lambda and coupling \Lambda\Lambda-\Xi N interactions are derived within G-matrix procedure fr...
0311084v1
2004-02-13
QCD sum rules at finite density in the large-N_c limit: The coupling of the rho-nucleon system to the D_{13}(1520)
QCD sum rules are studied for the vector-isovector current at finite baryon density in the limit of large number of colors N_c. For the condensate side it is shown that in this limit the four-quark condensate factorizes also for the finite density case. At the hadronic side the medium dependence is expressed in terms o...
0402048v1
2004-06-02
On the Isovector Channels in Relativistic Point Coupling Models within the Hartree and Hartree-Fock Approximations
We investigate the consequences of Fierz transformations acting upon the contact interactions for nucleon fields occurring in relativistic point coupling models in Hartree approximation, which yield the same models but in Hartree-Fock approximation instead. We find for four-fermion interactions occurring in two existin...
0406006v1
2004-11-30
Tensor coupling and pseudospin symmetry in nuclei
In this work we study the contribution of the isoscalar tensor coupling to the realization of pseudospin symmetry in nuclei. Using realistic values for the tensor coupling strength, we show that this coupling reduces noticeably the pseudospin splittings, especially for single-particle levels near the Fermi surface. By ...
0411120v2
2005-03-29
Mass and $KΛ$ coupling of $N^*(1535)$
Using resonance isobar model and effective Lagrangian approach, from recent BES results on $J/\psi\to\bar pp\eta$ and $\psi\to\bar pK^+\Lambda$, we deduce the ratio between effective coupling constants of $N^*(1535)$ to $K\Lambda$ and $p\eta$ to be $R\equiv g_{N^*(1535)K\Lambda}/g_{N^*(1535)p\eta} =1.3\pm 0.3$. With pr...
0503069v1
2006-02-10
XCDCC: Core Excitation in the Breakup of Exotic Nuclei
The eXtended Continuum Discretized Coupled Channel (XCDCC) method is developed to treat reactions where core degrees of freedom play a role. The projectile is treated as a multi-configuration coupled channels system generated from a valence particle coupled to a deformed core which is allowed to excite. The coupled cha...
0602034v1
2006-05-19
Failure of the Standard Coupled-Channels Method in Describing the Inelastic Reaction Data: On the Use of a New Shape for the Coupling Potential
We present the failure of the standard coupled-channels method in explaining the inelastic scattering together with other observables such as elastic scattering, excitation function and fusion data. We use both microscopic double-folding and phenomenological deep potentials with shallow imaginary components. We argue t...
0605045v1
2006-09-21
Covariant response theory beyond RPA and its application
The covariant particle-vibration coupling model within the time blocking approximation is employed to supplement the Relativistic Random Phase Approximation (RRPA) with coupling to collective vibrations. The Bethe-Salpeter equation in the particle-hole channel with an energy dependent residual particle-hole (p-h) inter...
0609061v1
2007-02-20
Application of density dependent parametrization models to asymmetric nuclear matter
Density dependent parametrization models of the nucleon-meson effective couplings, including the isovector scalar \delta-field, are applied to asymmetric nuclear matter. The nuclear equation of state and the neutron star properties are studied in an effective Lagrangian density approach, using the relativistic mean fie...
0702064v1
2007-03-28
The Friedrichs-Model with fermion-boson couplings
In this work we present an extended version of the Friedrichs Model, which includes fermion-boson couplings. The set of fermion bound states is coupled to a boson field with discrete and continuous components. As a result of the coupling some of the fermion states may become resonant states. This feature suggests the e...
0703090v1
1998-05-26
Fronts and interfaces in bistable extended mappings
We study the interfaces' time evolution in one-dimensional bistable extended dynamical systems with discrete time. The dynamics is governed by the competition between a local piece-wise affine bistable mapping and any couplings given by the convolution with a function of bounded variation. We prove the existence of tra...
9805006v1
1999-11-21
Coherence Resonance and Noise-Induced Synchronization in Globally Coupled Hodgkin-Huxley Neurons
The coherence resonance (CR) of globally coupled Hodgkin-Huxley neurons is studied. When the neurons are set in the subthreshold regime near the firing threshold, the additive noise induces limit cycles. The coherence of the system is optimized by the noise. A bell-shaped curve is found for the peak height of power spe...
9911048v1
2000-08-17
Studies of Coupled Cavity Linac (CCL) Accelerating Structures with 3-D Codes
The cw CCL being designed for the Accelerator Production of Tritium (APT) project accelerates protons from 96MeV to 211MeV. It consists of 99 segments each containing up to seven accelerating cavities. Segments are coupled by intersegment coupling cavities and grouped into supermodules. The design method needs to addre...
0008107v2
2001-08-30
Global selection rule in chemical coupling
Coupling and decoupling of chemical reactions are explored through a modified heat balance equation. Reaction enthalpies are found to play crucial role; the sign of their product for a pair of consecutive chemical reactions determine whether they couple or not. The possibility of a coupling-uncoupling transition for su...
0108070v1
2004-05-31
Maple procedures for the coupling of angular momenta. VI. LS-jj transformations
Transformation matrices between different coupling schemes are required, if a reliable classification of the level structure is to be obtained for open-shell atoms and ions. While, for instance, relativistic computations are traditionally carried out in jj-coupling, a LSJ coupling notation often occurs much more approp...
0405156v1
2004-12-20
Theory of the propagation of coupled waves in arbitrarily-inhomogeneous stratified media
We generalize the invariant imbedding theory of the wave propagation and derive new invariant imbedding equations for the propagation of arbitrary number of coupled waves of any kind in arbitrarily-inhomogeneous stratified media, where the wave equations are effectively one-dimensional. By doing this, we transform the ...
0412121v1
2006-04-05
Spurious detection of phase synchronization in coupled nonlinear oscillators
Coupled nonlinear systems under certain conditions exhibit phase synchronization, which may change for different frequency bands or with presence of additive system noise. In both cases, Fourier filtering is traditionally used to preprocess data. We investigate to what extent the phase synchronization of two coupled R\...
0604039v1
2006-06-17
Chaotic synchronization in coupled spatially extended beam-plasma systems
The appearance of the chaotic synchronization regimes has been discovered for the coupled spatially extended beam-plasma Pierce systems. The coupling was introduced only on the right bound of each subsystem. It has been shown that with coupling increase the spatially extended beam-plasma systems show the transition fro...
0606157v1
1997-05-06
Effective Theories of Coupled Classical and Quantum Variables from Decoherent Histories: A New Approach to the Backreaction Problem
We use the decoherent histories approach to quantum theory to derive the form of an effective theory describing the coupling of classical and quantum variables. The derivation is carried out for a system consisting of a large particle coupled to a small particle with the important additional feature that the large part...
9705005v2
1998-11-17
Pulse Sequences for NMR Quantum Computers: How to Manipulate Nuclear Spins While Freezing the Motion of Coupled Neighbours
We show how to divide a coupled multi-spin system into a small subset of ``active'' spins that evolve under chemical shift or scalar coupling operators, and a larger subset of ``spectator'' spins which are returned to their initial states, as if their motion had been temporarily frozen. This allows us to implement basi...
9811043v1
1999-03-30
Adiabatic population transfer via multiple intermediate states
This paper discusses a generalization of stimulated Raman adiabatic passage (STIRAP) in which the single intermediate state is replaced by $N$ intermediate states. Each of these states is connected to the initial state $\state{i}$ with a coupling proportional to the pump pulse and to the final state $\state{f}$ with a ...
9903096v1
2000-01-11
Adiabatic Output Coupling of a Bose Gas at Finite Temperatures
We develop a general theory of adiabatic output coupling from trapped atomic Bose-Einstein Condensates at finite temperatures. For weak coupling, the output rate from the condensate, and the excited levels in the trap, settles in a time proportional to the inverse of the spectral width of the coupling to the output mod...
0001033v2
2002-10-04
An Analysis of Mutual Communication between Qubits by Capacitive Coupling
A behavior of a two qubit system coupled by the electric capacitance has been studied quantum mechanically. We found that the interaction is essentially the same as the one for the dipole-dipole interaction; i.e., qubit-qubit coupling of the NMR quantum gate. Therefore a quantum gate could be constructed by the same op...
0210028v5
2003-11-14
Coupling Efficiencies in Single Photon On-Demand Sources
Many quantum computation and communication schemes require, or would significantly benefit from, true sources of single photon on-demand (SPOD). Unfortunately, such sources do not exist. It is becoming increasingly clear that coupling photons out of a SPOD source will be a limiting factor in many SPOD implementations. ...
0311099v2
2004-08-26
Quantum dynamics of a model for two Josephson-coupled Bose--Einstein condensates
In this work we investigate the quantum dynamics of a model for two single-mode Bose--Einstein condensates which are coupled via Josephson tunneling. Using direct numerical diagonalisation of the Hamiltonian, we compute the time evolution of the expectation value for the relative particle number across a wide range of ...
0408161v2
2004-11-06
Intrinsic decoherence effects on tripartite GHZ state generation using a trapped ion coupled to an optical cavity
We analyse the effects of intrinsic decoherence on the probability of generating a tripartite GHZ state using a cool trapped ion coupled to a single mode of the cavity field and interacting with a resonant laser field. Milburn equation is solved for this tripartite system to obtain the time evolution of density matrix ...
0411045v1
2005-01-20
Entanglement production in Quantized Chaotic Systems
Quantum chaos is a subject whose major goal is to identify and to investigate different quantum signatures of classical chaos. Here we study entanglement production in coupled chaotic systems as a possible quantum indicator of classical chaos. We use coupled kicked tops as a model for our extensive numerical studies. W...
0501113v1
2005-02-28
Control of Local Relaxation Behavior in Closed Bipartite Quantum Systems
We investigate the decoherence of a spin 1/2 subsystem weakly coupled to an environment of many spins 1/2 with and without mutual coupling. The total system is closed, its state is pure and evolves under Schroedinger dynamics. Nevertheless, the considered spin typically reaches a quasi-stationary equilibrium state. Her...
0502181v2