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2003-03-28
QCD sum rule analysis of the coupling constants g_{ρηγ} and g_{ωηγ}
The coupling constants g$_{\rho\eta\gamma}$ and g$_{\omega\eta\gamma}$ are calculated using QCD sum rules method by studying the three point ${\rho\eta\gamma}$ and ${\omega\eta\gamma}$ correlation functions. A comparison of the results with the values of the coupling constants that are deduced from the experimentally m...
0303244v1
2003-04-26
Anomalous quartic boson couplings via gamma gamma --> WW and gamma gamma --> WWZ at the TESLA kinematics
The production of two and three electroweak gauge bosons in the high-energy $\gamma\gamma$ collisions gives the well opportunity to probe anomalous quartic gauge boson couplings. The influence of five possible anomalous couplings on the cross sections for $W^+W^-$, $W^+W^-\gamma$, $W^+W^-Z$ productions has been investi...
0304250v2
2003-05-18
Chiral Symmetry Breaking with Scalar Confinement
Spontaneous chiral symmetry breaking is accepted to occur in low energy hadronic physics, resulting in the several successful theorems of PCAC. On the other hand scalar confinement is suggested both by the spectroscopy of hadrons and by the string picture of confinement. However these two evidences are apparently confl...
0305198v1
2003-05-19
Standard-model coupling constants from compositeness
A coupling-constant definition is given based on the compositeness property of some particle states with respect to the elementary states of other particles. It is applied in the context of the vector-spin-1/2-particle interaction vertices of a field theory, and the standard model. The definition reproduces Weinberg's ...
0305211v1
2003-05-26
Meson-Baryon Scattering in QCD_2 for any Coupling
Extending earlier work on strong-coupling meson-baryon scattering in QCD_2, we derive the effective meson-baryon action for any value of the coupling constant, in the large-N_c limit. Colour degrees of freedom play an important role, and we show that meson-baryon scattering can be formulated as a relativistic potential...
0305292v2
2003-08-04
A QCD Axion from Higher Dimensional Gauge Field
We point out that a QCD axion solving the strong CP problem can arise naturally from parity-odd gauge field C_M in 5-dimensional (5D) orbifold field theory. The required axion coupling to the QCD anomaly comes from the 5D Chern-Simons coupling, and all other unwanted U(1)_{PQ} breaking axion couplings can be avoided na...
0308024v1
2003-08-05
Gauge Coupling Unification and Neutrino Masses in 5D SUSY SO(10)
In this talk I discuss the problems and virtues of SUSY GUTs in four dimensions. I then show how to solve some of these problems, without foregoing the virtues, by considering an SO(10) SUSY GUT in five dimensions. I discuss gauge coupling unification and neutrino masses. In particular, it is shown that the 5D compacti...
0308052v1
2003-08-29
Pomeron fan diagrams with an infrared cutoff and running coupling
By direct numerical calculations the influence of a physically relevant infrared cutoff and running coupling on the gluon density and structure function of a large nucleus is studied in the perturbative QCD approach. It is found that the infrared cutoff changes the solutions very little. Running of the coupling produce...
0308320v1
2003-09-02
Photon polarization with anomalous right-handed top couplings in $B\to K_{res}γ$
The effect of anomalous right-handed top couplings on the photon polarization in $B\to K_{\rm res}\gamma$ is investigated. It is recently reported that the photon polarization can be measured through the up-down asymmetry of the photon direction relative to the subsequent $K_{\rm res}$ decay plane. We find that the ano...
0309018v1
2003-10-14
Analytic structure in the coupling constant plane in perturbative QCD
We investigate the analytic structure of the Borel-summed perturbative QCD amplitudes in the complex plane of the coupling constant. Using the method of inverse Mellin transform, we show that the prescription dependent Borel-Laplace integral can be cast, under some conditions, into the form of a dispersion relation in ...
0310169v1
2003-12-02
Towards a renormalizable standard model without fundamental Higgs scalar
We investigate the possibility of constructing a renormalizable standard model with purely fermionic matter content. The Higgs scalar is replaced by point-like fermionic self-interactions with couplings growing large at the Fermi scale. An analysis of the UV behavior in the point-like approximation reveals a variety of...
0312034v1
2003-12-21
Two loop renormalization of the magnetic coupling in hot QCD
Well above the critical temperature hot QCD is described by 3d electrostatic QCD with gauge coupling $g_E$ and Debye mass $m_E$. We integrate out the Debye scales to two loop accuracy and find for the gauge coupling in the resulting magnetostatic action $g_M^2=g_E^2(1-{1\over{48}}{g_E^2N\over{\pi m_E}} -{17\over{4608}}...
0312307v3
2004-01-06
Spin and parity of a possible baryon antidecuplet
The recently postulated existence of a baryon antidecuplet [1] can be reproduced in strong coupling theory in which a bare baryon spin 1/2 octet interacts with an octet of pseudoscalar mesons. When a suitable mixture of F- and D-type Yukawa couplings is chosen the dressed baryons group themselves into an infinite numbe...
0401023v1
2004-01-21
Phenomenological analysis of lepton and quark Yukawa couplings in SO(10) two Higgs model
We investigate a model that the Yukawa coupling form is constructed by two kinds of matrix (M_0 and M_1). For example, in the SO(10) GUT model, M_0 and M_1 are Yukawa couplings generated by the 10 and 126 Higgs scalars. We study how this model can give the observed mass and mixings of quarks and leptons. Parameter fitt...
0401154v1
2004-05-04
Strong and Yukawa two-loop contributions to Higgs scalar boson self-energies and pole masses in supersymmetry
I present results for the two-loop self-energy functions for neutral and charged Higgs scalar bosons in minimal supersymmetry. The contributions given here include all terms involving the QCD coupling, and those following from Feynman diagrams involving Yukawa couplings and scalar interactions that do not vanish as the...
0405022v3
2004-07-21
Universality of the rho-meson coupling in effective field theory
It is shown that both the universal coupling of the rho-meson and the Kawarabayashi-Suzuki-Riadzuddin-Fayyazuddin expression for the magnitude of its coupling constant follow from the requirement that chiral perturbation theory of pions, nucleons, and rho-mesons is a consistent effective field theory. The prerequisite ...
0407239v1
2004-07-30
On the strong-coupling effects in jet bremsstrahlung in the heavy flavor decays
We address the strong-coupling regime effects in the light-like quark jets where the radiated gluons are hard but highly collinear. These may lead to additional contributions in the invariant mass (or recoil energy) spectra, on top of the Fermi motion of the initial heavy quark in decays like b->s+\gamma. It is shown t...
0407359v1
2004-08-10
How to study weakly coupled neutral vector bosons
A weakly coupled new neutral gauge boson, forming a narrow resonance, can be efficiently produced at e+e- colliders through radiative return processes if the collider energy is larger than the gauge boson mass. This contribution analyzes the sensitivity of a future linear collider for weakly coupled gauge bosons and br...
0408132v1
2004-08-13
Mass of D*_sJ(2317) and Coupled Channel Effect
The resonance D*_sJ (2317) which is considered to be the 1^3P_0 state composed of charm and strange quarks has been discovered recently. The measured mass, which is about 160 MeV lower than the mass of the 1^3P_0 state obtained from the potential model calculation by Godfrey and Isgur, was considered surprisingly low a...
0408154v1
2004-08-18
Phenomenology of Goldstino Couplings
A general coupling of the Goldstino to the matter field and the weak gravitational field is constructed based on the standard and the nonlinear Volkov-Akulov realization of SUSY. The resulting Lagrangian, which is invariant under SUSY transformations, can give rise to explicit interactions which couple the helicity +-1...
0408210v2
2004-08-24
Determination of the HWW and HZZ Couplings at the LHC
The weak boson fusion process for neutral Higgs boson production is investigated with particular attention to the accuracy with which the Higgs boson couplings to weak bosons can be determined in final states that contain a Higgs boson plus at least two jets at CERN Large Hadron Collider energies. We determine that an ...
0408259v1
2004-08-30
SU(3) Clebsch-Gordan Coefficients for Baryon-Meson Coupling at Arbitrary N_c
We present explicit formulae for the SU(3) Clebsch-Gordan coefficients that are relevant for the couplings of large N_c baryons to mesons. In particular, we compute the Clebsch-Gordan series for the coupling of the octet (associated with mesons, and remains the correct representation at large N_c) to the large N_c anal...
0408342v1
2004-11-05
Partly Supersymmetric Grand Unification
It is shown how grand unification can occur in models which are partly supersymmetric. The particle states which are composite do not contribute to the running of gauge couplings above the compositeness scale, while the elementary states contribute the usual large logarithmns. This introduces a new differential running...
0411090v1
2004-11-07
Evolution of coupled classical fields
We study the evolution of the coupled scalar and fermion fields within the classical field theory. We examine the case of N coupled fields in 1+3 dimensional space. The general expressions for the fields distributions are obtained. The particular case of two fields in 1+1 dimensional space is carefully studied. We obta...
0411101v2
2005-01-15
Flavor changing scalar couplings and $tγ(Z)$ production at hadron colliders
We calculate the contributions of the flavor changing scalar ($FCS$) couplings arised from topcolor-assisted technicolor ($TC2$) models at tree-level to the $t\gamma$ and $tZ$ production at the Tevatron and $LHC$ experiments. We find that the production cross sections are very small at the Tevatron with $\sqrt{s}=1.96T...
0501131v1
2005-02-13
Electroweak phase transition and Higgs self-couplings in the two-Higgs-doublet model
We calculate both the cubic and the quartic self-couplings of the lighter scalar Higgs boson without assuming the decoupling limit in the two-Higgs-doublet model (THDM). In some regions of parameter space of the THDM where the electroweak phase transition is strongly first order, it is possible that the quartic self-co...
0502116v1
2005-03-07
Two-loop QCD gauge coupling at high temperatures
We determine the 2-loop effective gauge coupling of QCD at high temperatures, defined as a matching coefficient appearing in the dimensionally reduced effective field theory. The result allows to improve on one of the classic non-perturbative probes for the convergence of the weak-coupling expansion at high temperature...
0503061v1
2005-08-01
Determining the Stau Trilinear Coupling A_tau in Supersymmetric Higgs Decays
The measurement of the trilinear couplings A in the part of the Lagrangian which breaks supersymmetry softly will be a difficult experimental task. In this report the heavy Higgs decays H,A -> stau_1 stau_2 to stau pairs are investigated for measuring the stau trilinear coupling A_tau. Based on detailed simulations of ...
0508021v1
2005-08-25
Higgs bosons in Left-Right symmetric Randall-Sundrum models
We study the corrections to Higgs physics in a model of a single warped extra dimension with all fields except the Higgs in the bulk, and a gauge symmetry extended to $SU(2)_L\times SU(2)_R \times U(1)_{B-L}$. We find that generically the Higgs coupling to electroweak gauge boson pairs is suppressed, the coupling to gl...
0508266v1
2005-09-15
Probing the Universal Randall-Sundrum Model at the ILC
The Randall-Sundrum model with all Standard Model (SM) fields in the bulk, including the Higgs, can be probed by precision measurements at the ILC. In particular, the couplings of the Higgs to the gauge bosons of the SM can be determined with high accuracy at the ILC. Here we examine the deviations in these couplings f...
0509160v2
2005-10-13
Collider Bounds on Pseudoscalars Coupling to Gauge Bosons
We bound the coupling of pseudo-scalar particles to Tr G^G_{QCD} using (the lack of) monojet plus missing E_T events at the Tevatron, and estimate the bounds obtainable from LHC. In addition, we revisit the bounds on the coupling to F^F_{EM} from e^+e^- collider events with single photon and missing E_T final states. T...
0510183v2
2005-11-15
Axion interpretation of the PVLAS data?
The PVLAS collaboration has recently reported the observation of a rotation of the polarization plane of light propagating through a transverse static magnetic field. Such an effect can arise from the production of a light, m_A ~ meV, pseudoscalar coupled to two photons with coupling strength g_{A\gamma} ~ 5x10^{-6} Ge...
0511184v1
2005-12-04
Couplings of the eta and eta' Mesons to the Nucleon
The couplings of the eta and eta' mesons to the nucleon are obtained from the U_A(1) Goldberger-Treiman relation. The chiral symmetry breaking corrections are very large and bring the calculated values of the coupling constants G_etaNN and G_eta'NN close to values obtained from potential models.
0512048v3
2005-12-05
Four-Loop Decoupling Relations for the Strong Coupling
We compute the matching relation for the strong coupling constant within the framework of QCD up to four-loop order. This allows a consistent five-loop running (once the $\beta$ function is available to this order) taking into account threshold effects. As a side product we obtain the effective coupling of a Higgs boso...
0512058v1
2005-12-05
QCD Decoupling at Four Loops
We present the matching condition for the strong coupling contant alpha_s at a heavy quark threshold to four loops in the modified minimal subtraction scheme. Our results lead to further decrease of the theoretical uncertainty of the evolution of the strong coupling constant through heavy quark thresholds. Using a low ...
0512060v1
2006-01-01
Phases of a fermionic model with chiral condensates and Cooper pairs in 1+1 dimensions
We study the phase structure of a 4-fermi model with three bare coupling constants, which potentially has three types of bound states. This model is a generalization of the model discussed previously by A. Chodos et al. [Phys. Rev. D 61, 045011 (2000)], which contained both chiral condensates and Cooper pairs. For this...
0601007v1
2006-02-07
Stable gapless superconductivity at strong coupling
We study cross-flavor Cooper pairing in a relativistic system of two fermion species with mismatched Fermi surfaces. We find that there exist gapless phases which are characterized by either one or two gapless nodes in the energy spectra of their quasiparticles. An analysis of the current-current correlator reveals tha...
0602065v1
2006-02-16
Investigation of g_f0-rho-gamma and g_a0-rho-gamma coupling constants in light cone sum rules
We present a calculation of the coupling constant f0-->rho-gamma of and a0-->rho-gamma decays from the point of the light cone QCD sum rules. We estimate the coupling constants g_f0-rho-gamma and g_a0-rho-gamma which are an essential ingredient in the analysis of physical processes involving isoscalar f0(980) and isove...
0602147v1
2006-04-29
Grand Unification in the SO(10) Model
Extrapolating the coupling strengths to very high energies, one finds that they do not converge to a single coupling constant, as expected in the simplest gauge theory of Grand Unification, the SU(5) theory. We find that the coupling constants do converge, provided that two new intermediate energy scales are introduced...
0605004v1
2006-05-10
Higgs + 2 Jets as a Probe for CP Properties
Azimuthal angle correlations of the jets in Hjj events at the LHC provide a probe of the CP nature of Higgs couplings to gauge bosons. In weak boson fusion the HWW and HZZ couplings are tested. Gluon fusion processes probe the tensor structure of the effective Hgg vertex and thus the CP nature of the dominant quark cou...
0605117v1
2006-07-19
Comment on "Mass and KΛCoupling of the N*(1535)"
We comment on a recent paper by B.C. Liu and B.S. Zou [Phys. Rev. Lett. 96, 042002 (2006)] where it was argued that the coupling of the N*(1535) to K\Lambda is even larger than its coupling to the \eta N channel. Specifically, we point out that recently measured Dalitz plot distributions for pp -> pK^+\Lambda provide c...
0607212v1
2006-08-04
Shear viscosity in weakly coupled ${\cal N} {=} 4$ Super Yang-Mills theory compared to QCD
We compute the shear viscosity of weakly coupled N=4 supersymmetric Yang-Mills (SYM) theory. Our result for [eta/s], the viscosity to entropy-density ratio, is many times smaller than the corresponding weak-coupling result in QCD. This suggests that [eta/s] of QCD near the transition point is several times larger than ...
0608062v2
2006-08-28
Anomalous Higgs Couplings at an $e γ$ Collider
We examine the sensitivity of $e \gamma$ colliders (based on $e^+ e^-$ linear colliders of c.m. energy 500 GeV) to the anomalous couplings of the Higgs to W-bosons via the process $e^- \gamma \longrightarrow \nu W H$. This has the advantage over $e^+ e^-$ collider in being able to dissociate WWH vertex from ZZH. We are...
0608293v1
2006-10-19
Phenomenology of infrared finite gluon propagator and coupling constant
We report on some recent solutions of the Dyson-Schwinger equations for the infrared behavior of the gluon propagator and coupling constant, discussing their differences and proposing that these different behaviors can be tested through hadronic phenomenology. We discuss which kind of phenomenological tests can be appl...
0610256v2
2006-10-24
QCD sum rule approach to the new mesons and the $g_{D_{sJ}DK}$ coupling constant
We use diquark-antidiquark currents to investigate the masses and partial decay widths of the recently observed mesons $D_{sJ}^{+}(2317)$, $D_0^{*0}(2308)$ and X(3872), considered as four-quark states, in a QCD sum rule approach. In particular we investigate the coupling constant $g_{D_{sJ}DK}$. We found that the $g_{D...
0610320v1
2006-12-12
Scalar form factor of the nucleon and nucleon--scalar meson coupling constant in QCD
Scalar form factor of the nucleon is calculated in the framework of light cone QCD sum rules, using the most general form of the baryon current. Using the result on scalar form factor of the nucleon, the nucleon-scalar "sigma" and "a_0" meson coupling constants are estimated. Our results on these couplings are in good ...
0612144v2
2006-12-12
To see the exotic Theta^+ baryon from interference
Since all couplings of the exotic $\Theta^+$ baryon to normal hadrons seem to be small it is hard to reveal it in standard resonance searching. We suggest to look for the $\Theta^+$ production in interference with a known resonance yielding the same final state but having a high production rate. The interference proces...
0612150v1
2007-01-14
Thermal production of gravitinos
We reconsider thermal production of gravitinos in the early universe, adding to previously considered 2 -> 2 gauge scatterings: a) production via 1 -> 2 decays, allowed by thermal masses; b) the effect of the top Yukawa coupling; c) a proper treatment of the reheating process. Our final result behaves physically (large...
0701104v2
2007-02-19
The BFKL Pomeron in the weak and strong coupling limits and kinematical constraints
We show that a resummation model for the evolution kernel at small x creates a bridge between the weak and strong couplings. The resummation model embodies DGLAP and BFKL anomalous dimensions at leading logarithmic orders, as well as a kinematical constraint on the real emission part of the kernel. In the case of pure ...
0702195v1
2007-03-07
Small Shear Viscosity of a Quark-Gluon Plasma Implies Strong Jet Quenching
We derive an expression relating the transport parameter $\hat{q}$ and the shear viscosity $\eta$ of a weakly coupled quark-gluon plasma. A deviation from this relation can be regarded as a quantitative measure of ``strong coupling'' of the medium. The ratio $T^3/\hat{q}$, where $T$ is the temperature, is a more broadl...
0703082v3
1992-01-17
Spectrum of Two-Dimensional (Super)Gravity
We review the BRST analysis of the system of a (super)conformal matter coupled to 2D (super)gravity. The spectrum and its operator realization are reported. In particular, the operators associated with the states of nonzero ghost number are given. We also discuss the ground ring structure of the super-Liouville coupled...
9201034v1
1992-01-29
Coupling of Tachyons and Discrete States in $c = 1$ 2-D Gravity
All the three point couplings involving tachyons and/or discrete states are obtained in $c=1$ two-dimensional (2-D) quantum gravity by means of the operator product expansion (OPE). Cocycle factors are found to be necessary in order to maintain the analytic structure of the OPE, and are constructed explicitly both for ...
9201065v2
1992-02-18
Axion Couplings and Effective Cut-Offs in Superstring Compactifications
We use the linear supermultiplet formalism of supergravity to study axion couplings and chiral anomalies in the context of field-theoretical Lagrangians describing orbifold compactifications beyond the classical approximation. By matching amplitudes computed in the effective low energy theory with the results of string...
9202059v1
1992-03-28
Current Algebra of WZNW Models at and away from Criticality
We derive the current algebra of principal chiral models with a Wess-Zumino term. At the critical coupling where the model becomes conformally invariant (Wess-Zumino-Novikov-Witten theory), this algebra reduces to two commuting Kac-Moody algebras, while in the limit where the coupling constant is taken to zero (ordinar...
9203075v1
1992-04-13
Moduli Corrections to Gauge and Gravitational Couplings in four dimensional Superstrings
We study one-loop, moduli-dependent corrections to gauge and gravitational couplings in supersymmetric vacua of the heterotic string. By exploiting their relation to the integrability condition for the associated CP-odd couplings, we derive general expressions for them, both for $(2,2)$ and $(2,0)$ models, in terms of ...
9204030v2
1992-07-26
Deviations from Scale Invariance near a General Conformal Background
Deviations from scale invariance resulting from small perturbations of a general two dimensional conformal field theory are studied. They are expressed in terms of beta functions for renormalization of general couplings under local change of scale. The beta functions for homogeneous background are given perturbatively ...
9207085v1
1992-12-07
Superstring Threshold Corrections to Yukawa Couplings
A general method of computing string corrections to the K\"ahler metric and Yukawa couplings is developed at the one-loop level for a general compactification of the heterotic superstring theory. It also provides a direct determination of the so-called Green-Schwarz term. The matter metric has an infrared divergent par...
9212045v1
1993-03-10
Role of Short Distance Behavior in Off-Shell Open-String Field Theory
A recent proposal for a background independent open string field theory is studied in detail for a class of backgrounds that correspond to general quadratic boundary interactions on the world-sheet. A short-distance cut-off is introduced to formulate the theory with a finite number of local and potentially unrenormaliz...
9303067v1
1993-04-28
A remark on the coupling-dependence in affine Toda field theories
The affine Toda field theories based on the non simply-laced Lie algebras are discussed. By rewriting the S-matrix formulae found by Delius et al, a universal form for the coupling-constant dependence of these models is obtained, and related to various general properties of the classical couplings. This is illustrated ...
9304149v1
1993-05-09
Breaking of Topological Symmetry
The coupling of topological matter to topological Yang-Mills theory in four dimensions is considered and a model is presented. It is shown that, contrary to the two-dimensional case, this coupling leads to a breaking of the topological symmetry. This means that the vacuum expectation values of the observables of the th...
9305028v2
1993-07-19
Nonlinear Renormalization Group Equation for Matrix Models
An exact renormalization group equation is derived for the free energy of matrix models. The renormalization group equation turns out to be nonlinear for matrix models, as opposed to linear for vector models. An algorithm for determining the critical coupling constant and the critical exponent is obtained. As concrete ...
9307116v2
1993-08-15
Information Retrieval from a Charge `Trap'
We study the model of massless $1+1$ electrodynamics with nonconstant coupling, introduced by Peet, Susskind and Thorlacius as the `charge hole'. But we take the boundary of the strong coupling region to be first timelike, then spacelike for a distance $X$, and then timelike again (to mimic the structure of a black hol...
9308069v1
1993-08-25
Continuum Strong Coupling Expansion of Yang-Mills Theory: Quark Confinement and Infra-Red Slavery
We solve Schr\"odinger's equation for the ground-state of {\it four}-dimensional Yang-Mills theory as an expansion in inverse powers of the coupling. Expectation values computed with the leading order approximation are reduced to a calculation in {\it two}-dimensional Yang-Mills theory which is known to confine. Conseq...
9308116v2
1993-08-26
Extending the Theory of Random Surfaces
The theory of embedded random surfaces, equivalent to two--dimensional quantum gravity coupled to matter, is reviewed, further developed and partly generalized to four dimensions. It is shown that the action of the Liouville field theory that describes random surfaces contains terms that have not been noticed previousl...
9308121v1
1993-08-27
A String Project in Multicolour QCD
Some old and new evidence for the existence of the string (planar random surfaces) representation of multicolour QCD are reviewed. They concern the random surface representation of the strong coupling expansion in lattice multicolour gauge theory in any dimension. Our old idea of modified strong coupling expansion in t...
9308135v1
1993-10-22
Scalar Fields Coupled to Four-Dimensional Lattice Gravity
I discuss some results we have obtained recently in a lattice model for quantized gravity coupled to scalar matter in four dimensions. We have looked at how the continuous phase transition separating the smooth from the rough phase of gravity is influenced by the presence of the scalar field. We find that close to the ...
9310152v1
1994-01-10
An Exact Solution to O(26) Sigma Model coupled to 2-D Gravity
By a mapping to the bosonic string theory, we present an exact solution to the O(26) sigma model coupled to 2-D quantum gravity. In particular, we obtain the exact gravitational dressing to the various matter operators classified by the irreducible representations of O(26). We also derive the exact form of the gravitat...
9401038v1
1994-04-28
Multiple Ising Spins Coupled to 2d Quantum Gravity
We study a model in which p independent Ising spins are coupled to 2d quantum gravity (in the form of dynamical planar phi-cubed graphs). Consideration is given to the p tends to infinity limit in which the partition function becomes dominated by certain graphs; we identify most of these graphs. A truncated model is so...
9404174v1
1994-06-09
Maintaining coherence in Quantum Computers
The effect of the inevitable coupling to external degrees of freedom of a quantum computer are examined. It is found that for quantum calculations (in which the maintenance of coherence over a large number of states is important), not only must the coupling be small but the time taken in the quantum calculation must be...
9406058v1
1994-06-21
Frustrating and Diluting Dynamical Lattice Ising Spins
We investigate what happens to the third order ferromagnetic phase transition displayed by the Ising model on various dynamical planar lattices (ie coupled to 2D quantum gravity) when we introduce annealed bond disorder in the form of either antiferromagnetic couplings or null couplings. We also look at the effect of s...
9406138v1
1994-06-28
Quantum Backreaction on ``Classical'' Variables
A mathematically consistent procedure for coupling quasiclassical and quantum variables through coupled Hamilton-Heisenberg equations of motion is derived from a variational principle. During evolution, the quasiclassical variables become entangled with the quantum variables with the result that the value of the quasic...
9406182v2
1994-07-22
Gravitationally Dressed Conformal Field Theory and Emergence of Logarithmic Operators
We study correlation functions in two-dimensional conformal field theory coupled to induced gravity in the light-cone gauge. Focussing on the fermion four-point function, we display an unexpected non-perturbative singularity structure: coupling to gravity {\it qualitatively} changes the perturbative $(x_1-x_2)^{-1}(x_3...
9407151v1
1994-08-12
From Weak to Strong Coupling in Two-Dimensional Gravity
The strong coupling physics of two dimensional gravity at C=7, 13, 19 is deciphered, by building up on previous works along the same line (for a recent review, of the background material, see hep-th/9408069). It is shown that chirality becomes deconfined. The string suceptibility is derived, and found to be real contra...
9408076v1
1995-01-10
Strong/Weak Coupling Duality from the Dual String
On compactification to six spacetime dimensions, the fundamental heterotic string admits as a soliton a dual string whose effective worldsheet action couples to the background fields of the dual formulation of six-dimensional supergravity. On further toroidal compactification to four spacetime dimensions, the dual stri...
9501030v2
1995-03-18
INSTANTON CALCULATIONS VERSUS EXACT RESULTS IN 4 DIMENSIONAL SUSY GAUGE THEORIES.
We relate the non-perturbative exact results in supersymmetry to perturbation theory using several different methods: instanton calculations at weak or strong coupling, a method using gaugino condensation and another method relating strong and weak coupling. This allows many precise numerical checks of the consistency ...
9503115v1
1995-04-06
One-loop Renormalization of Black Hole Entropy Due to Non-minimally Coupled Matter
The quantum entanglement entropy of an eternal black hole is studied. We argue that the relevant Euclidean path integral is taken over fields defined on $\alpha$-fold covering of the black hole instanton. The statement that divergences of the entropy are renormalized by renormalization of gravitational couplings in the...
9504022v1
1995-04-18
Integrable Quartic Potentials and Coupled KdV Equations
We show a surprising connection between known integrable Hamiltonian systems with quartic potential and the stationary flows of some coupled KdV systems related to fourth order Lax operators. In particular, we present a connection between the Hirota-Satsuma coupled KdV system and (a generalisation of) the $1:6:1$ integ...
9504087v1
1995-06-14
Gauge-Yukawa Unification and The Top Quark Mass
The principles of finiteness and reduction of couplings can be applied to achieve Gauge-Yukawa Unification. It is found that the observed top-bottom hierarchy and the top quark mass naturally follow if there exists Gauge-Yukawa Unification which is a simple functional relation among the gauge coupling and the Yukawa co...
9506092v1
1995-06-21
N=1 super-Chern-Simons coupled to parity-preserving matter from Atiyah-Ward space-time
In this letter, we present the Parkes-Siegel formulation for the massive Abelian $N$$=$$1$ super-{\QED} coupled to a self-dual supermultiplet, by introducing a chiral multiplier superfield. We show that after carrying out a suitable dimensional reduction from ($2$$+$$2$) to ($1$$+$$2$) dimensions, and performing some n...
9506146v2
1995-07-03
Interacting Wess-Zumino-Novikov-Witten Models
We study the system of two WZNW models coupled to each other via the current-current interaction. The system is proven to possess the strong/weak coupling duality symmetry. The strong coupling phase of this theory is discussed in detail. It is shown that in this phase the interacting WZNW models approach non-trivial co...
9507004v1
1995-08-03
Anisotropy beta functions
The flow of couplings under anisotropic scaling of momenta is computed in $\phi^3$ theory in 6 dimensions. It is shown that the coupling decreases as momenta of two of the particles become large, keeping the third momentum fixed, but at a slower rate than the decrease of the coupling if all three momenta become large s...
9508014v1
1995-11-05
Dilatonic gravity near two dimensions as a string theory
Using the renormalization-group formalism, a sigma model of a special type- in which the metric and the dilaton depend explicitly on one of the string coordinates only-is investigated near two dimensions. It is seen that dilatonic gravity coupled to N scalar fields can be expressed in this form, using a string parametr...
9511031v1
1995-12-12
Randomly coupled minimal models
Using 1-loop renormalisation group equations, we analyze the effect of randomness on multi-critical unitary minimal conformal models. We study the case of two randomly coupled $M_p$ models and found that they flow in two decoupled $M_{p-1}$ models, in the infra-red limit. This result is then extend to the case with $M$...
9512087v2
1996-04-10
Prepotential of N=2 SU(2) Yang-Mills gauge theory coupled with a massive matter multiplet
We discuss the N=2 SU(2) Yang-Mills theory coupled with a massive matter in the weak coupling. In particular, we obtain the instanton expansion of its prepotential. Instanton contributions in the mass-less limit are completely reproduced. We study also the double scaling limit of this massive theory and find that the p...
9604051v2
1996-05-02
One loop corrections to coupling constants in String Effective Field Theory
In the framework of a recently proposed method for computing exactly string amplitudes regularized in the infra-red, I determine the one-loop correlators for auxiliary fields in the symmetric $Z_2\times Z_2$ orbifold model. The $D$-field correlation function turns out to give the one-loop corrections for the gauge coup...
9605012v1
1996-05-04
4 D Quantum N-Dilaton Gravity and One-Loop Divergence of Effective Action on Constant Dilaton
We consider 4D quantum gravity with N-dilatons with the most general couplings. Especially, on constant dilaton and arbitrary metric background, we show the structure of the divergent terms. We show the constraint between the couplings necessary to cancel the coefficient of the square of the Wyle tensor. Next we show t...
9605025v1
1996-05-06
SUSY Gauge Dynamics and Singularities of 4d N=1 String Vacua
Many N=1 heterotic string compactifications exhibit physically mysterious singularities at codimension one in the moduli space of vacua. At these singularities, Yukawa couplings of charged fields develop poles as a function of the moduli. We explain these conformal field theory singularities, in a class of examples, as...
9605036v1
1996-05-23
Interaction energy of Chern-Simons vortices in the gauged O(3) sigma model
The purpose of this Letter is to present a computation of the interaction energy of gauged O(3) Chern-Simons vortices which are infinitely separated. The results will show the behaviour of the interaction energy as a function of the constant coupling the potential, which measures the relative strength of the matter sel...
9605177v1
1996-06-18
A Canticle on (4,0) Supergravity-Scalar Multiplet Systems for a ``Cognoscente''
Extending prior investigations, we study three of the the four distinct minimal (4,0) scalar multiplets coupled to (4,0) supergravity. It is found that the scalar multiplets manifest their differences at the component level by possessing totally different couplings to the supergravity fields. Only the SM-I multiplet po...
9606108v1
1996-06-20
Supergravity Coupled to Chiral and Yang-Mills Matter at One Loop
We present the full result for the divergent one-loop contribution to the effective boson Lagrangian for supergravity coupled to chiral and Yang-Mills supermultiplets. We also consider the specific case of dilaton couplings in effective supergravity Lagrangians from superstrings, for which the one-loop result is consid...
9606135v1
1996-06-27
A Yang--Mills Theory in Loop Space and Chapline--Manton Coupling
We consider a Yang--Mills theory in loop space whose gauge group is a Kac--Moody group with the central extension. From this theory, we derive a local field theory constructed of Yang--Mills fields and abelian antisymmetric and symmetric tensor fields of the second rank. The Chapline--Manton coupling, that is, coupling...
9606178v1
1996-07-16
The Branching of Graphs in 2-d Quantum Gravity
The branching ratio is calculated for three different models of 2d gravity, using dynamical planar phi-cubed graphs. These models are pure gravity, the D=-2 Gaussian model coupled to gravity and the single spin Ising model coupled to gravity. The ratio gives a measure of how branched the graphs dominating the partition...
9607136v1
1996-07-30
Spontaneous Symmetry Breaking at Two Loop in 3-d Massless Scalar Electrodynamics
In three dimensional Maxwell-Chern-Simons massless scalar electrodynamics with $ \phi^6$ coupling, the $U(1)$ symmetry is spontaneously broken at two loop order regardless of the presence or absence of the Maxwell term. Dimensional transmutation takes place in pure Chern-Simons scalar electrodynamics. The beta function...
9607233v2
1996-08-28
Chiral Decomposition For Non-Abelian Bosons
We study the non-abelian extension for the splitting of a scalar field into chiral components. Using this procedure we find a non ambiguous way of coupling a non abelian chiral scalar field to gravity. We start with a (non-chiral) WZW model covariantly coupled to a background metric and, after the splitting, arrive at ...
9608187v1
1996-09-17
Periods, Coupling Constants and Modular Functions in N=2 SU(2) SYM with Massive Matter
We determine the mass dependence of the coupling constant for N=2 SYM with N_f=1,2,3 and 4 flavours. All these cases can be unified in one analytic expression, given by a Schwarzian triangle function. Moreover we work out the connection to modular functions which enables us to give explicit formulas for the periods. Us...
9609130v2
1996-10-28
A Large N Chiral Transition on a Plaquette
We construct a model of a chiral transition using the well known large N transition in two dimensional U(N) lattice gauge theory. Restricting the model to a single plaquette, we introduce Grassmann variables on the corners of the plaquette with the natural phase factors of staggered fermions and couple them to the U(N)...
9610225v1
1996-11-05
String-Inspired Gravity Coupled to Yang-Mills Fields
String-inspired 1+1-dimensional gravity is coupled to Yang-Mills fields in the Cangemi-Jackiw gauge-theoretical formulation, based on the extended Poincar\'e group. A family of couplings, which involves metrics obtainable from the physical metric with a conformal rescaling, is considered, and the resulting family of mo...
9611028v1
1996-11-07
Renormalization In Coupled-Abelian Self-Dual Chern-Simons Models
An algebraic restriction of the nonabelian self-dual Chern-Simons-Higgs systems leads to coupled-abelian self-dual models with intricate mass spectra. The vacua are characterized by embeddings of SU(2) into the gauge algebra; and in the broken phases, the gauge and real scalar masses are related to the exponents of the...
9611046v1
1996-11-18
Flow of low energy couplings in the Wilson renormalization group
A new form of the Wilson renormalization group equation is derived, in which the flow equations are, up to linear terms, proportional to a gradient flow. A set of co\"ordinates is found in which the flow of marginal, low-energy, couplings takes a gradient form, if relevant couplings are tuned to vanish.
9611132v3
1997-01-13
On the strongly coupled heterotic string
We analyze in detail the anomaly cancellation conditions for the strongly coupled $E_8 \times E_8$ heterotic string introduced by Horava and Witten and find new features compared to the ten-dimensional Green-Schwarz mechanism. We project onto ten dimensions the corresponding Lagrangian of the zero-mode fields. We find ...
9701048v2