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47
1992-07-05
$V'Z$ and $V'W$ Production as Tests of Heavy Gauge Boson Couplings at Future Hadron Colliders
We point out that the production cross section of $pp\to V'V$, with $V'=W',Z'$ and $V=W,Z$ is a useful diagnostic of $V'$ gauge couplings at future hadron colliders. For $M_{Z'}\simeq1$ TeV it would allow determination of combinations of $Z'$ gauge couplings to the quarks to around 10 percent. An analysis of the extrac...
9207216v1
1993-03-01
On the Unification of Couplings in the Minimal Supersymmetric Standard Model
The unification of gauge and Yukawa couplings within the minimal supersymmetric standard model is studied at the two loop level. We derive an expression for the effective scale, $T_{SUSY}$, which characterizes the supersymmetric particle threshold corrections to the gauge couplings, and demonstrate that $T_{SUSY}$ is o...
9303202v1
1993-07-11
Baryon-Pion Couplings from Large-N QCD
We derive a set of consistency conditions for the pion-baryon coupling constants in the large-N limit of QCD. The consistency conditions have a unique solution which are precisely the values for the pion-baryon coupling constants in the Skyrme model. We also prove that non-relativistic $SU(2N_f)$ spin-flavor symmetry (...
9307241v1
1994-03-22
Constraints on Baryon-Nonconserving Yukawa Couplings in a Supersymmetric Theory
The 1-loop evolution of couplings in the minimal supersymmetric standard model, extended to include baryon nonconserving $(B\!\!\!/)$ operators through explicit $R$-parity violation, is considered keeping only $B\!\!\!/$ superpotential terms involving the maximum possible number of third generation superfields. If all ...
9403350v2
1995-05-19
NEW PHYSICS AND RECENT HIGH PRECISION ELECTROWEAK MEASUREMENTS
We analyze LEP and SLC data from the 1995 Winter Conferences for signals of new physics. We compare the data with the Standard Model (SM) as well as a number of test hypotheses concerning the nature of new physics: (i) nonstandard Zbb couplings, (ii) nonstandard Zff couplings for the entire third generation, (iii) nons...
9505339v1
1995-06-24
Large $R$-parity Violating Couplings and Grand Unification
We consider a possibility that $R$-parity violating interactions of particles which do not involve the first generation have large (up to 1) coupling constants, $\Lambda$. Such couplings, if exist, could have a number of phenomenological consequences: renormalization of $b-\tau$ mass ratio, generation of $\nu_\tau$ mas...
9506416v2
1995-11-27
Radiative corrections to neutrino-majoron couplings
It is claimed that radiative corrections maintain the proportionality between the neutrino mass and the neutrino-majoron coupling and never give rise to enhanced decay rates in conventional majoron models. The coupling of a majoron to neutrinos is calculated at one loop level in various models, including the singlet ma...
9511416v1
1996-07-24
Unitarity Constraints on Anomalous Top Quark Couplings to Weak Gauge Bosons
If there is new physics associated with the top quark, it could show up as anomalous couplings of the top quark to weak gauge bosons, such as $Z\ttbar$ and $W\tbbar$ vector and axial-vector couplings. We use the processes $\ttbar\to Z^0Z^0$, $\ttbar\to W^+W^-$, and $\ttbar\to Z^0H$ to obtain the unitarity constraints o...
9607413v2
1997-06-03
Naive Dimensional Analysis and Supersymmetry
In strongly-coupled theories with no small parameters, there are factors of 4\pi that appear when the couplings of the low-energy effective lagrangian are written in units of the effective cutoff \Lambda. These numerical factors can be explained using "naive dimensional analysis." We extend these ideas to supersymmetri...
9706235v1
1998-04-17
Study of Trilinear Gauge Boson Couplings at the Tevatron Collider
We review studies of the trilinear gauge boson couplings at the Tevatron proton-antiproton collider from data collected by the CDF and D0 collaborations during the period 1992--1996. The gauge boson couplings are a fundamental prediction of the standard model, resulting from the non-Abelian nature of the theory. Theref...
9804322v2
1998-04-23
Solving a Coupled Set of Truncated QCD Dyson-Schwinger Equations
Truncated Dyson-Schwinger equations represent finite subsets of the equations of motion for Green's functions. Solutions to these non-linear integral equations can account for non-perturbative correlations. A closed set of coupled Dyson-Schwinger equations for the propagators of gluons and ghosts in Landau gauge QCD is...
9804376v1
1998-08-13
Units and Numerical Values of the Effective Couplings in Perturbative Heterotic String Vacua
We determine the units and numerical values for a class of couplings in the effective theory of perturbative heterotic string vacua, with the emphasis on the correct translation between the canonical gauge coupling g and Planck scale M_Planck ~ 1.2 x 10^19 GeV as used in the effective theory description and the string ...
9808321v1
1999-05-31
Mirage Gauge Coupling Unification and TeV Scale Strings
We consider gauge coupling unification in models with TeV scale strings and large compact dimensions realized as type IIB string orientifolds. Following an observation by Ibanez we show that the gauge couplings at low energies can behave as if they effectively unify at $M_U \sim 2 \times 10^{16} GeV$ with $\alpha_U \si...
9905577v1
1999-06-01
Bounds on R-parity Violating Couplings at the Weak Scale and at the GUT Scale
We present an update of the most stringent experimental bounds on the trilinear R-parity violating couplings. We then analyse bounds on the R-parity violating couplings at the unification scale by renormalising the weak scale bounds. We derive unification scale upper bounds upon the couplings which are broadly independ...
9906209v2
2000-09-05
Probing Anomalous Top Quark Couplings at the Future Linear Colliders
In terms of an effective Lagrangian we investigate the possibilities of probing anomalous top quark couplings, $t \bar{t} H$, $\gamma t \bar{t}$, $Z t \bar{t}$ and $tWb$ at the future linear colliders. It is found that probing anomalous top quark couplings, $t \bar{t} H$, $\gamma t \bar{t}$, $Z t \bar{t}$ and $tWb$ at ...
0009047v2
2000-10-31
A Constraint on Yukawa-Coupling Unification from Lepton-Flavor Violating Processes
We present a new constraint on a lepton mixing matrix $V$ from lepton-flavor violating (LFV) processes in supersymmetric standard models with massive neutrinos. Here, we assume Yukawa-coupling unification $f_{\nu 3}\simeq f_{\rm top}$, in which $\tau$-neutrino Yukawa coupling $f_{\nu 3}$ is unified into top-quark Yukaw...
0010348v1
2000-12-14
Trilinear Neutral Gauge Boson Couplings in Effective Theories
We list all the lowest dimension effective operators inducing off-shell trilinear neutral gauge boson couplings Z-Z-Photon, Z-Photon-Photon, and ZZZ within the effective Lagrangian approach, both in the linear and nonlinear realizations of the SU(2)_{L} X U(1)_Y gauge symmetry. In the linear scenario we find that these...
0012180v1
2001-04-10
Freezing of QCD coupling affects the short distance static potential
A striking contradiction between lattice short range static potential (nf=0) and standard perturbative potential, observed by Bali G.S., is investigated in the framework of the background perturbation theory. With the use of the background coupling which contains the only background parameter - mass mB, fixed by fine s...
0104097v5
2001-07-10
Measuring effective electroweak couplings in single top production at the LHC
We study the mechanism of single top production at the LHC in the framework of an effective electroweak Lagrangian, analyzing the sensitivity of different observables to the magnitude of the effective couplings that parametrize new physics beyond the Standard Model. The observables relevant to the distinction between l...
0107112v1
2001-08-29
Yukawa coupling quantum corrections to the self couplings of the lightest MSSM Higgs boson
A detailed analysis of the top-quark/squark quantum corrections to the lightest CP-even Higgs boson (h^0) self-couplings is presented in the MSSM. By considering the leading one-loop Yukawa-coupling contributions of O(m_t^4), we discuss the decoupling behaviour of these corrections when the top-squarks are heavy compar...
0108245v2
2001-10-17
Constraints on heavy Z' couplings from ΔS = 2 B^- -> K^- K^- π^+ decay
The heavy Z' boson with family nonuniversal couplings can introduce flavour changing effects. Constraints on nondiagonal Z' couplings coming from the \mu-e conversion in a muonic atom, K^0 - \bar{K^0} and B - \bar{B} mixing, epsilon and epsilon'/ \epsilon CP- violating coefficients have been already established. By usi...
0110233v1
2002-01-30
Neutrinoless Double Beta Decay with R-parity Violation
We consider recently observed neutrinoless double beta decay in the context of the minimal supersymmetric standard model with R-parity violating couplings lambda^{'}. We observe that most of the current experimental bounds on the R-parity violating couplings do not exclude the possibility that the neutrinoless double b...
0201277v3
2002-09-19
Triple gauge couplings in polarised e-e+ -> W-W+ and their measurement using optimal observables
The sensitivity of optimal integrated observables to electroweak triple gauge couplings is investigated for the process e-e+ -> W-W+ -> 4 fermions at future linear colliders. By a suitable reparameterisation of the couplings we achieve that all 28 coupling parameters have uncorrelated statistical errors and are natural...
0209229v1
2003-07-24
Models of quintessence coupled to the electromagnetic field and the cosmological evolution of alpha
We study the change of the effective fine structure constant in the cosmological models of a scalar field with a non-vanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place empirical constraints on the size of the possible coupling and explore a large class of ...
0307299v2
2003-11-19
Weak Isospin Violations in Charged and Neutral Higgs Couplings from SUSY Loop Corrections
Supersymmetric QCD and supersymmetric electroweak loop corrections to the violations of weak isospin to Yukawa couplings are investigated. Specifically it involves an analysis of the supersymmetric loop corrections to the Higgs couplings to the third generation quarks and leptons. Here we analyze the SUSY loop correcti...
0311242v1
2004-06-16
On the determination of the structure of the scalar Higgs boson's couplings to vectorbosons
In this paper we investigate the determination of the coupling structure of a Higgs boson at the LHC using angular correlations in the decay chain H -> ZZ -> 4l. We consider the most general couplings of a scalar to spin 1 particles and compare the angular correlations of the decay products using a maximum likelihood m...
0406181v1
2004-07-16
Determination of Higgs-boson couplings at the LHC
We investigate the determination of Higgs boson couplings to gauge bosons and fermions at the LHC from data on Higgs boson production and decay. We demonstrate that very mild theoretical assumptions, which are valid in general multi-Higgs doublet models, are sufficient to allow the extraction of absolute values of the ...
0407190v1
2005-08-01
Next-to-Leading Order QCD Corrections to the Direct Top Quark Production via Model-independent FCNC Couplings at Hadron Colliders
We calculated the next-to-leading order (NLO) QCD corrections to the cross sections for direct top quark productions induced by model--independent flavour changing neutral current couplings at hadron colliders. The NLO results increase the experimental sensitivity to the anomalous couplings. Our results show that the N...
0508016v4
2005-08-11
Effective-Lagrangian approach to gamma gamma --> WW; II: Results and comparison with e+e- --> WW
We present a study of anomalous electroweak gauge-boson couplings which can be measured in e+e- and gamma gamma collisions at a future linear collider like ILC. We consider the gauge-boson sector of a locally SU(2) x U(1) invariant effective Lagrangian with ten dimension-six operators added to the Lagrangian of the Sta...
0508133v2
2005-12-07
Running coupling at finite temperature and chiral symmetry restoration in QCD
We analyze the running gauge coupling at finite temperature for QCD, using the functional renormalization group. The running of the coupling is calculated for all scales and temperatures. At finite temperature, the coupling is governed by a fixed point of the 3-dimensional theory for scales smaller than the correspondi...
0512085v2
2006-01-06
All Order Running Coupling BFKL Evolution from GLAP (and vice-versa)
We present a systematic formalism for the derivation of the kernel of the BFKL equation from that of the GLAP equation and conversely to any given order, with full inclusion of the running of the coupling. The running coupling is treated as an operator, reducing the inclusion of running coupling effects and their facto...
0601049v2
2006-07-12
Heavy flavor diffusion in weakly coupled N=4 Super Yang-Mills theory
We use perturbation theory to compute the diffusion coefficient of a heavy quark or scalar moving in N=4 SU(N_c) Super Yang-Mills plasma to leading order in the coupling and the ratio T/M<<1. The result is compared both to recent strong coupling calculations in the same theory and to the corresponding weak coupling res...
0607148v3
2006-08-12
Current algebra derivation of temperature dependence of hadron couplings with currents
The vector and the axial-vector meson couplings with the vector and the axial-vector currents respectively at finite temperature have been obtained in Ref. \cite{Mallik} by calculating all the relevant one-loop Feynman graphs with vertices obtained from the effective chiral Lagrangian. On the other hand, the same coupl...
0608141v1
2006-12-06
The single t-quark productions via the flavor-changing processes in the topcolor-assisted technicolor model at the hadron colliders
In the framework of topcolor-assisted technicolor(TC2) model, there exist tree-level flavor-changing (FC) couplings which can result in the loop-level FC coupling $tcg$. Such $tcg$ coupling can contribute significant clues at the forthcoming Large Hadron Collider (LHC) experiments. In this paper, based on the TC2 model...
0612063v1
2007-03-20
Anomalous Higgs Couplings in the $SO(5)\times U(1)_{B-L}$ Gauge-Higgs Unification in Warped Spacetime
The gauge couplings $WWZ$, $WWWW$, and $WWZZ$ in the gauge-Higgs unification scenario in the Randall-Sundrum warped spacetime remain almost universal as in the standard model, but substantial deviation results for the Higgs couplings. In the $SO(5)\times U(1)_{B-L}$ model, the couplings $WWH$ and $ZZH$ are suppressed b...
0703212v3
1993-03-08
4D Quantum Gravity Coupled to Matter
We investigate the phase structure of four-dimensional quantum gravity coupled to Ising spins or Gaussian scalar fields by means of numerical simulations. The quantum gravity part is modelled by the summation over random simplicial manifolds, and the matter fields are located in the center of the 4-simplices, which c...
9303042v1
1993-07-03
Potential Flow Of The Renormalisation Group In A Simple Two Component Model
The renormalisation group (RG) flow on the space of couplings of a simple model with two couplings is examined. The model considered is that of a single component scalar field with $\phi^4$ self interaction coupled, via Yukawa coupling, to a fermion in flat four dimensional space. The RG flow on the two dimensional spa...
9307023v1
1994-01-14
The String Dilaton and a Least Coupling Principle
It is pointed out that string-loop modifications of the low-energy matter couplings of the dilaton may provide a mechanism for fixing the vacuum expectation value of a massless dilaton in a way which is naturally compatible with existing experimental data. Under a certain assumption of universality of the dilaton coupl...
9401069v1
1994-06-20
Coping With Strongly Coupled String Theory
String theory, if it describes nature, is probably strongly coupled. As a result, one might despair of making any statements about the theory. In the framework of a set of clearly spelled out assumptions, we show that this is not necessarily the case. Certain discrete gauge symmetries, combined with supersymmetry, tigh...
9406132v2
1995-05-06
Phase transition by curvature in three dimensional $O(N)$ sigma model
Using the effective potential, the large-$N$ nonlinear $O(N)$ sigma model with the curvature coupled term is studied on $S^2\times R^1$. We show that, for the conformally coupled case, the dynamical mass generation of the model in the strong-coupled regime on $R^3$ takes place for any finite scalar curvature (or radius...
9505036v2
1995-12-21
String Dynamics at Strong Coupling
The dynamics of superstring, supergravity and M theories and their compactifications are probed by studying the various perturbation theories that emerge in the strong and weak coupling limits for various directions in coupling constant space. The results support the picture of an underlying non-perturbative theory tha...
9512181v2
1996-02-15
The Strong-Coupling Spectrum of the Seiberg-Witten Theory
We carefully study the global structure of the solution of the $N=2$ supersymmetric pure Yang-Mills theory with gauge group $SU(2)$ obtained by Seiberg and Witten. We exploit its ${\bf Z}_2$-symmetry and describe the curve in moduli space where BPS states can become unstable, separating the strong-coupling from the wea...
9602082v3
1996-06-17
Non-Uniqueness of Quantized Yang-Mills Theories
We consider quantized Yang-Mills theories in the framework of causal perturbation theory which goes back to Epstein and Glaser. In this approach gauge invariance is expressed by a simple commutator relation for the S-matrix. The most general coupling which is gauge invariant in first order contains a two-parametric amb...
9606100v1
1996-10-18
On the weak coupling spectrum of N=2 supersymmetric SU(n) gauge theory
The weak coupling spectrum of BPS saturated states of pure $N=2$ supersymmetric SU$(n)$ gauge theory is investigated. The method uses known results on the dyon spectrum of the analogous theory with $N=4$ supersymmetry, along with the action on these states of the semi-classical monodromy transformations. For dyons whos...
9610142v1
1997-10-27
Finite quantum field theories: Clifford algebras for Yukawa couplings?
By imposing on the most general renormalizable quantum field theory the requirement of the absence of ultraviolet-divergent renormalizations of the physical parameters (masses and coupling constants) of the theory, finite quantum field theories in four space-time dimensions may be constructed. Famous prototypes of thes...
9710202v1
1997-11-24
Clifford algebras in finite quantum field theories II. Reducible Yukawa finiteness condition
An arbitrary renormalizable quantum field theory is considered as finite if its dimensionless couplings conspire to yield, at every order of its perturbative expansion, no ultraviolet-divergent renormalizations of the physical parameters of the theory. The "finiteness conditions" resulting from these requirements form ...
9711176v1
1998-06-20
Coupling of M-Branes in M-Theory
Coupling of a membrane and a five-brane to the bosonic sector of D=11 supergravity is considered. The five--brane is a dyonic object which carries both an electric and a magnetic charge of the D=11 three-form gauge field $A^3$, and it couples not only to $A^3$ but also minimally couples to a six-form field $A^6$ dual t...
9806175v1
1998-11-09
Super Yang-Mills at Weak, Intermediate and Strong Coupling
We consider three dimensional SU(N) N=1 super-Yang-Mills compactified on the space-time R X S^1 X S^1. In particular, we compactify the light-cone coordinate x^- on a light-like circle via DLCQ, and wrap the remaining transverse coordinate on a spatial circle. By retaining only the first few excited modes in the transv...
9811083v1
2000-05-03
A Yang-Mills Theory in Loop Space and Generalized Chapline-Manton Coupling
We consider a Yang-Mills theory in loop space with an affine Lie gauge group. The Chapline-Manton coupling, the coupling between Yang-Mills fields and an abelian antisymmetric tensor field of second rank via the Chern-Simons term, is systematically derived within the framework of the Yang-Mills theory. The generalized ...
0005030v2
2001-04-05
Gauge-Invariant Couplings of Noncommutative Branes to Ramond-Ramond Backgrounds
We derive the couplings of noncommutative D-branes to spatially varying Ramond-Ramond fields, extending our earlier results in hep-th/0009101. These couplings are expressed in terms of *n products of operators involving open Wilson lines. Equivalence of the noncommutative to the commutative couplings implies interestin...
0104045v2
2001-07-03
On The Strong-Coupling Spectrum of Pure SU(3) Seiberg-Witten Theory
We consider the two complex dimensional moduli space of supersymmetric vacua for low energy effective N=2 SYM with gauge group SU(3). We describe, at the topological level, a consistent model of how the relevant curves of marginal stability (CMS) intertwine with the branch cuts to partition the moduli space into pieces...
0107016v2
2001-09-14
Complete Cubic and Quartic Couplings of 16 and $\bar {16}$ in SO(10) Unification
A recently derived basic theorem on the decomposition of SO(2N) vertices is used to obtain a complete analytic determination of all SO(10) invariant cubic superpotential couplings involving $16_{\pm}$ semispinors of SO(10) chirality $\pm$ and tensor representations. In addition to the superpotential couplings computed ...
0109116v2
2001-10-04
Bulk versus brane running couplings
A simplified higher dimensional Randall-Sundrum-like model in 6 dimensions is considered. It has been observed previously by Goldberger and Wise that in such a self-interacting scalar theory on the bulk with a conical singularity there is mixing of renormalization of 4d brane couplings with that of the bulk couplings. ...
0110051v1
2002-12-05
Supersymmetric Yang-Mills theories with local coupling: The supersymmetric gauge
Supersymmetric pure Yang-Mills theory is formulated with a local, i.e. space-time dependent, complex coupling in superspace. Super-Yang-Mills theories with local coupling have an anomaly, which has been first investigated in the Wess-Zumino gauge and there identified as an anomaly of supersymmetry. In a manifest supers...
0212064v2
2003-01-26
Conformal Invariance, Anomalous Gravitational Coupling and Derivation of a Particle Concept
We study a gravitational model whose vacuum sector is invariant under conformal transformations. In this model we investigate the anomalous gravitational coupling of the large-scale matter. In this kind of coupling the large-sale matter is taken to couple to a metric which is different but conformally related to the me...
0301208v2
2003-04-11
Dimensionally reduced gravity theories are asymptotically safe
4D Einstein gravity coupled to scalars and abelian gauge fields in its 2-Killing vector reduction is shown to be quasi-renormalizable to all loop orders at the expense of introducing infinitely many essential couplings. The latter can be combined into one or two functions of the `area radius' associated with the two Ki...
0304117v1
2003-10-20
Exact Wall Solutions in 5-Dimensional SUSY QED at Finite Coupling
A series of exact BPS solutions are found for single and double domain walls in N=2 supersymmetric (SUSY) QED for finite gauge coupling constants. Vector fields are found to be massive, although it is localized on the wall. Massless modes can be assembled into a chiral scalar multiplet of the preserved N=1 SUSY, after ...
0310189v2
2004-04-08
The Strong-Coupling Expansion and the Ultra-local Approximation in Field Theory
We discuss the strong-coupling expansion in Euclidean field theory. In a formal representation for the Schwinger functional, we treat the off-diagonal terms of the Gaussian factor as a perturbation about the remaining terms of the functional integral. We first study the strong-coupling expansion in the \phi^4 theory an...
0404070v1
2004-06-29
Coupling constant dependence of the shear viscosity in N=4 supersymmetric Yang-Mills theory
Gauge theory - gravity duality predicts that the shear viscosity of N=4 supersymmetric SU(N_c) Yang-Mills plasma at temperature T in the limit of large N_c and large 't Hooft coupling g^2_{YM} N_c is independent of the coupling and equals to \pi N_c^2 T^3/8. In this paper, we compute the leading correction to the shear...
0406264v3
2004-11-25
A dual gravity study of the 2+1D compact U(1) gauge theory coupled with strongly interacting matter fields
We consider the D2-brane probe action in the gravity background dual to N coincident Dp-branes by treating the separation between the D2- and Dp-branes as a nondynamical parameter for $p=2,4,6$. The gauge coupling, the core size of a non-BPS instanton and the mass gap of the compact U(1) gauge theory in the D2-brane ar...
0411239v3
2006-05-23
Anomalies, Anomalous U(1)'s and generalized Chern-Simons terms
A detailed analysis of anomalous U(1)'s and their effective couplings is performed both in field theory and string theory. It is motivated by the possible relevance of such couplings in particle physics, as well as a potential signal distinguishing string theory from other UV options. The most general anomaly related e...
0605225v2
2004-08-27
Stochastic Dynamics of a Coupled Atmosphere--Ocean Model
The investigation of the coupled atmosphere-ocean system is not only scientifically challenging but also practically important. We consider a coupled atmosphere-ocean model, which involves hydrodynamics, thermodynamics, and random atmospheric dynamics due to short time influences at the air-sea interface. We reformul...
0408386v1
2002-05-04
Random Coupling of Chaotic Maps leads to Spatiotemporal Synchronisation
We investigate the spatiotemporal dynamics of a network of coupled chaotic maps, with varying degrees of randomness in coupling connections. While strictly nearest neighbour coupling never allows spatiotemporal synchronization in our system, randomly rewiring some of those connections stabilises entire networks at $x^*...
0205008v1
2002-11-08
Diffusive transport and self-consistent dynamics in coupled maps
The study of diffusion in Hamiltonian systems has been a problem of interest for a number of years. In this paper we explore the influence of self-consistency on the diffusion properties of systems described by coupled symplectic maps. Self-consistency, i.e. the back-influence of the transported quantity on the veloc...
0211011v1
2002-11-22
Emergence of patterns in driven and in autonomous spatiotemporal systems
The relationship between a driven extended system and an autonomous spatiotemporal system is investigated in the context of coupled map lattice models. Specifically, a locally coupled map lattice subjected to an external drive is compared to a coupled map system with similar local couplings plus a global interaction. I...
0211041v1
2003-05-07
Dynamics of FitzHugh-Nagumo excitable systems with delayed coupling
Small lattices of $N$ nearest neighbor coupled excitable FitzHugh-Nagumo systems, with time-delayed coupling are studied, and compared with systems of FitzHugh-Nagumo oscillators with the same delayed coupling. Bifurcations of equilibria in N=2 case are studied analytically, and it is then numerically confirmed that th...
0305010v1
2004-04-28
Parameter mismatches,variable delay times and synchronization in time-delayed systems
We investigate synchronization between two unidirectionally linearly coupled chaotic non-identical time-delayed systems and show that parameter mismatches are of crucial importance to achieve synchronization. We establish that independent of the relation between the delay time in the coupled systems and the coupling de...
0404050v1
2005-03-31
Synchronization in driven versus autonomous coupled chaotic maps
The phenomenon of synchronization occurring in a locally coupled map lattice subject to an external drive is compared to the synchronization process in an autonomous coupled map system with similar local couplings plus a global interaction. It is shown that chaotic synchronized states in both systems are equivalent, bu...
0504001v1
2005-10-13
Modulational instability in asymmetric coupled wave functions
The evolution of the amplitude of two nonlinearly interacting waves is considered, via a set of coupled nonlinear Schroedinger-type equations. The dynamical profile is determined by the wave dispersion laws (i.e. the group velocities and the GVD terms) and the nonlinearity and coupling coefficients, on which no assumpt...
0510029v2
2005-12-17
Synchronous Behavior of Coupled Systems with Discrete Time
The dynamics of one-way coupled systems with discrete time is considered. The behavior of the coupled logistic maps is compared to the dynamics of maps obtained using the Poincare sectioning procedure applied to the coupled continuous-time systems in the phase synchronization regime. The behavior (previously considered...
0512045v1
2006-05-25
Predictions of ultra-harmonic oscillations in coupled arrays of limit cycle oscillators
Coupled distinct arrays of nonlinear oscillators have been shown to have a regime of high frequency, or ultra-harmonic, oscillations that are at multiples of the natural frequency of individual oscillators. The coupled array architectures generate an in-phase high-frequency state by coupling with an array in an anti-ph...
0605045v2
2006-09-18
Complete chaotic synchronization in mutually coupled time-delay systems
Complete chaotic synchronization of end lasers has been observed in a line of mutually coupled, time-delayed system of three lasers, with no direct communication between the end lasers. The present paper uses ideas from generalized synchronization to explain the complete synchronization in the presence of long coupling...
0609047v3
2006-09-21
Scaling properties of invariant densities of coupled Tchebyscheff maps
We study 1-dimensional coupled map lattices consisting of diffusively coupled Tchebyscheff maps of N-th order. For small coupling constants a we determine the invariant 1-point and 2-point densities of these nonhyperbolic systems in a perturbative way. For arbitrarily small couplings a>0 the densities exhibit a selfsim...
0609052v2
1999-07-06
Coupled-channels analysis of the $^{\bf 16}$O+$^{\bf 208}$Pb fusion barrier distribution
Analyses using simplified coupled-channels models have been unable to describe the shape of the previously measured fusion barrier distribution for the doubly magic $^{16}$O+$^{208}$Pb system. This problem was investigated by re-measuring the fission excitation function for $^{16}$O+$^{208}$Pb with improved accuracy an...
9907003v1
1995-07-14
Theory of Multiphonon Excitation in Heavy-Ion Collisions
We study the effects of channel coupling in the excitation dynamics of giant resonances in relativistic heavy ions collisions. For this purpose, we use a semiclassical approximation to the Coupled-Channels problem and separate the Coulomb and the nuclear parts of the coupling into their main multipole components. In or...
9507027v1
1997-06-28
Importance of Non-Linear Couplings in Fusion Barrier Distributions and Mean Angular Momenta
The effects of higher order coupling of surface vibrations to the relative motion on heavy-ion fusion reactions at near-barrier energies are investigated. The coupled channels equations are solved to all orders, and also in the linear and the quadratic coupling approximations. It is shown that the shape of fusion barri...
9706083v1
2000-04-05
Pseudovector versus pseudoscalar coupling in kaon photoproduction - revisited
The question of pseudovector versus pseudoscalar coupling schemes for the kaon-hyperon-nucleon interaction is re-examined for the reaction $\gamma p\to K^+ \Lambda$ in several isobaric models. These models typically include Born terms, $K^*$- and $K_1$-exchange in the t-channel, and a few different combinations of spin...
0004007v1
2000-05-14
A New Coupling Potential for the Scattering of Deformed Light Heavy-Ions
This letter introduces a new coupling potential to explain the experimental data over wide energy ranges for a number of systems. Within the coupled-channels formalism, this letter first shows the limitations of the standard coupled-channels theory in the case where one of the nuclei in the reaction is strongly deforme...
0005035v4
2001-05-06
An Analysis of the $^{12}$C+$^{12}$C Reaction Using a New Type of Coupling Potential
A new approach has been used to explain the experimental data for the $^{12}$C+$^{12}$C system over a wide energy range in the laboratory system from 32.0 MeV to 126.7 MeV. This new coupled-channels based approach involves replacing the usual first derivative coupling potential by a new, second-derivative coupling pote...
0105016v1
2001-11-06
Nuclear Ground State Observables and QCD Scaling in a Refined Relativistic Point Coupling Model
We present results obtained in the calculation of nuclear ground state properties in relativistic Hartree approximation using a Lagrangian whose QCD-scaled coupling constants are all natural (dimensionless and of order 1). Our model consists of four-, six-, and eight-fermion point couplings (contact interactions) toget...
0111012v2
2001-11-16
Effect of continuum couplings in fusion of halo $^{11}$Be on $^{208}$Pb around the Coulomb barrier
The effect of continuum couplings in the fusion of the halo nucleus $^{11}$Be on $^{208}$Pb around the Coulomb barrier is studied using a three-body model within a coupled discretised continuum channels (CDCC) formalism. We investigate in particular the role of continuum-continuum couplings. These are found to hinder t...
0111051v1
2002-02-21
The $ρNN$ coupling with direct coupling and loops
Starting from a gauge formalism of $\rho$ mesons, pions and baryons we evaluate the $\rho$ coupling to the nucleon, including the direct coupling provided by the Lagrangians, plus contributions from loops with the virtual pion cloud. We find a contribution to the magnetic $\rho$ coupling to the nucleon from pionic loop...
0202070v2
2004-07-01
Effective meson masses, effective meson-nucleon couplings and neutron star radii
Using the generalized mean field theory, we have studied the relation among the effective meson masses, the effective meson-nucleon couplings and the equation of state (EOS) in asymmetric nuclear matter. If the effective omega-meson mass becomes smaller at high density, the EOS becomes stiffer. However, if we require t...
0407004v1
2004-09-27
Nuclear Structure Calculations with Coupled Cluster Methods from Quantum Chemistry
We present several coupled-cluster calculations of ground and excited states of 4He and 16O employing methods from quantum chemistry. A comparison of coupled cluster results with the results of exact diagonalization of the hamiltonian in the same model space and other truncated shell-model calculations shows that the q...
0409062v1
1997-01-10
Synchronization of globally-coupled phase oscillators: singularities and scaling for general couplings
The onset of collective behavior in a population of globally coupled oscillators with randomly distributed frequencies is studied for phase dynamical models with arbitrary coupling; the effect of a stochastic temporal variation in the frequencies is also included. The Fokker-Planck equation for the coupled Langevin sys...
9701006v1
2005-08-12
Optimization of coupling between photonic crystal resonator and curved microfiber
The evanescent coupling from a photonic crystal resonator to a micron-thick optical fiber is investigated in detail by using a 3D-FDTD method. Properly designed photonic crystal cavity and taper structures are proposed, and optimal operating conditions are found to enhance the coupling strength while suppressing other ...
0508078v1
2006-03-31
On the Role of Penning Ionization in Photoassociation Spectroscopy
We study the role of Penning ionization on the photoassociation spectra of He(^3S)-He(^3S). The experimental setup is discussed and experimental results for different intensities of the probe laser are shown. For modelling the experimental results we consider coupled-channel calculations of the crossing of the ground s...
0603268v1
2006-06-14
Measurement of mutual inductance from frequency dependence of impedance of AC coupled circuit using digital dual-phase lock-in amplifier
We present a simple method to determine the mutual inductance $M$ between two coils in a coupled AC circuit by using a digital dual-phase lock-in amplifier. The frequency dependence of the real and imaginary parts is measured as the coupling constant is changed. The mutual inductance $M$ decreases as the distance $d$ b...
0606124v3
1999-02-09
Quantum gates by coupled asymmetric quantum dots and controlled-NOT-gate operation
A quantum computer based on an asymmetric coupled dot system has been proposed and shown to operate as the controlled-NOT-gate. The basic idea is (1) the electron is localized in one of the asymmetric coupled dots. (2)The electron transfer takes place from one dot to the other when the energy-levels of the coupled dots...
9902031v2
2003-06-14
Use of Quadrupolar Nuclei for Quantum Information processing by Nuclear Magnetic Resonance: Implementation of a Quantum Algorithm
Physical implementation of Quantum Information Processing (QIP) by liquid-state Nuclear Magnetic Resonance (NMR), using weakly coupled spin-1/2 nuclei of a molecule, is well established. Nuclei with spin$>$1/2 oriented in liquid crystalline matrices is another possibility. Such systems have multiple qubits per nuclei a...
0306100v1
2004-07-15
Superconducting Phase Qubit Coupled to a Nanomechanical Resonator: Beyond the Rotating-Wave Approximation
We consider a simple model of a Josephson junction phase qubit coupled to a solid-state nanoelectromechanical resonator. This and many related qubit-resonator models are analogous to an atom in an electromagnetic cavity. When the systems are weakly coupled and nearly resonant, the dynamics is accurately described by th...
0407106v1
2005-10-17
The effects of nonlinear couplings and external magnetic field on the thermal entanglement in a two-spin-qutrit system
We investigate the effects of nonlinear couplings and external magnetic field on the thermal entanglement in a two-spin-qutrit system by applying the concept of negativity. It is found that the nonlinear couplings favor the thermal entanglement creating. Only when the nonlinear couplings $|K|$ are larger than a certain...
0510129v1
2007-04-03
Spin-orbit coupling effect on the persistent currents in mesoscopic ring with an Anderson impurity
Based on the finite $U$ slave boson method, we have investigated the effect of Rashba spin-orbit(SO) coupling on the persistent charge and spin currents in mesoscopic ring with an Anderson impurity. It is shown that the Kondo effect will decrease the magnitude of the persistent charge and spin currents in this side-cou...
0704.0319v1
2007-05-17
The phase structure of a chirally invariant lattice Higgs-Yukawa model for small and for large values of the Yukawa coupling constant
We consider a chirally invariant lattice Higgs-Yukawa model based on the Neuberger overlap operator. As a first step towards the eventual determination of Higgs mass bounds we study the phase diagram of the model analytically in the large Nf-limit. We present an expression for the effective potential at tree-level in t...
0705.2539v2
2007-05-21
ATLAS sensitivity to Wtb anomalous couplings in top quark decays
We study the sensitivity of the ATLAS experiment to Wtb anomalous couplings in top pair production with semileptonic decay, pp -> t tbar -> W+ b W- bbar, with one of the W bosons decaying leptonically and the other hadronically. Several observables are examined, including the W helicity fractions and new quantities rec...
0705.3041v2
2007-06-18
Pomeron loop and running coupling effects in high energy QCD evolution
Within the framework of a (1+1)-dimensional model which mimics evolution and scattering in QCD at high energy, we study the influence of the running of the coupling on the high-energy dynamics with Pomeron loops. We find that the particle number fluctuations are strongly suppressed by the running of the coupling, by at...
0706.2540v1
2007-07-18
Photoinduced melting of charge order in a quarter-filled electron system coupled with different types of phonons
Photoinduced melting of charge order is calculated by using the exact many-electron wave function coupled with classically treated phonons in the one-dimensional quarter-filled Hubbard model with Peierls and Holstein types of electron-phonon couplings. The model parameters are taken from recent experiments on (EDO-TTF)...
0707.2619v1
2007-07-23
The multiple effects of gradient coupling on network synchronization
Recent studies have shown that synchronizability of complex networks can be significantly improved by asymmetric couplings, and increase of coupling gradient is always in favor of network synchronization. Here we argue and demonstrate that, for typical complex networks, there usually exists an optimal coupling gradient...
0707.3353v1
2007-07-25
Coupled-mode equations and gap solitons in a two-dimensional nonlinear elliptic problem with a separable periodic potential
We address a two-dimensional nonlinear elliptic problem with a finite-amplitude periodic potential. For a class of separable symmetric potentials, we study the bifurcation of the first band gap in the spectrum of the linear Schr\"{o}dinger operator and the relevant coupled-mode equations to describe this bifurcation. T...
0707.3731v2
2007-07-30
Tests of non-standard electroweak couplings of right-handed quarks
The standard model can be interpreted as the leading order of a Low-Energy Effective Theory (LEET) invariant under a higher non linearly realized symmetry $S_{nat}\supset SU(2)_W \times U(1)_Y$ equipped with a systematic power counting. Within the minimal version of this ``not quite decoupling'' LEET, the dominant non-...
0707.4194v2