127 research outputs found
The hermitian Wilson-Dirac operator in smooth SU(2) instanton backgrounds
We study the spectral flow of the hermitian Wilson-Dirac operator \ham(m)
as a function of in smooth SU(2) instanton backgrounds on the lattice. For
a single instanton background with Dirichlet boundary conditions on \ham(m),
we find a level crossing in the spectral flow of \ham(m), and we find the
shape of the crossing mode at the crossing point to be in good agreement with
the zero mode associated with the single instanton background. With
anti-periodic boundary conditions on \ham(m), we find that the instanton
background in the singular gauge has the correct spectral flow but the one in
regular gauge does not. We also investigate the spectral flows of two instanton
and instanton-anti-instanton backgrounds.Comment: 18 pages, Latex file, 12 postscript figure
Dual vortices in Abelian projected SU(2) in the Polyakov gauge
We study dual Abrikosov vortices in Abelian projected SU(2) gauge theory in
the Polyakov gauge. We show that vortices are present in this gauge but they
are suppressed with respect to the maximal Abelian gauge. We interpret this
difference in terms of the shielding of the electric charge by the charged
coset fields.Comment: Talk presented at LATTICE96(topology), 3 pages, latex, 4 eps figures,
uses epsfig and espcrc2.sty (included
Relations Between Low-lying Quantum Wave Functions and Solutions of the Hamilton-Jacobi Equation
We discuss a new relation between the low lying Schroedinger wave function of
a particle in a one-dimentional potential V and the solution of the
corresponding Hamilton-Jacobi equation with -V as its potential. The function V
is , and can have several minina (V=0). We assume the problem to be
characterized by a small anhamornicity parameter and a much smaller
quantum tunneling parameter between these different minima.
Expanding either the wave function or its energy as a formal double power
series in and , we show how the coefficients of
in such an expansion can be expressed in terms of definite
integrals, with leading order term determined by the classical solution of the
Hamilton-Jacobi equation. A detailed analysis is given for the particular
example of quartic potential .Comment: LaTex, 48 pages, no figur
A New Approach to Flavor Symmetry and an Extended Naturalness Principle
A class of non-supersymmetric extensions of the Standard Model is proposed in
which there is a multiplicity of light scalar doublets in a multiplet of a
non-abelian family group with the Standard Model Higgs doublet. Anthropic
tuning makes the latter light, and consequently the other scalar doublets
remain light because of the family symmetry. The family symmetry greatly
constrains the pattern of FCNC and proton decay operators coming from
scalar-exchange. Such models show that useful constraints on model-building can
come from an extended naturalness principle when the electroweak scale is
anthropically tuned.Comment: 31 pages, 3 figure
Baryons in Holographic QCD
We study the baryon in holographic QCD with multi- brane
system. In holographic QCD, the baryon appears as a topologically non-trivial
chiral soliton in a four-dimensional effective theory of mesons. We call this
topological soliton as Brane-induced Skyrmion. Some review of
holographic QCD is presented from the viewpoints of recent hadron physics and
phenomenologies. Four-dimensional effective theory with pions and mesons
is uniquely derived from the non-abelian Dirac-Born-Infeld (DBI) action of
brane with supergravity background, without small amplitude expansion of
meson fields to discuss chiral solitons. For the hedgehog configuration of pion
and -meson fields, we derive the energy functional and the Euler-Lagrange
equation of Brane-induced Skyrmion from the meson effective action induced by
holographic QCD. Performing the numerical calculation, we obtain the pion
profile and the -meson profile of the Brane-induced
Skyrmion, and estimate its total energy, energy density distribution, and
root-mean-square radius. These results are compared with the experimental
quantities of baryons and also with the profiles of standard Skyrmion without
mesons. We analyze interaction terms of pions and mesons in
Brane-induced Skyrmion, and consider the role of -meson component
appearing in baryons.Comment: 28 pages, 11 figure
Anomalous gauge couplings of the Higgs boson at high energy photon colliders
We study the sensitivity of testing the anomalous gauge couplings 's
of the Higgs boson in the formulation of linearly realized gauge symmetry via
the processes and at polarized and
unpolarized photon colliders based on linear colliders of
c.m.~energies 500 GeV, 1 TeV, and 3 TeV. Signals beyond the standard model (SM)
and SM backgrounds are carefully studied. We propose certain kinematic cuts to
suppress the standard model backgrounds. For an integrated luminosity of 1
ab, we show that (a) can provide a test of
to the sensitivity of
TeV at a 500 GeV ILC, and TeV at a 1 TeV ILC and a 3
TeV CLIC, and (b) at a 3 TeV CLIC can test all the
anomalous couplings 's to the sensitivity of
TeV.Comment: 30 pages, 17 figure
Introduction to light cone field theory and high energy scattering
In this set of four lectures, we provide an elementary introduction to light
cone field theory and some of its applications in high energy scattering.Comment: 28 pages, LaTeX, invited lectures at Cape Town summer school in
theoretical physic
Does quantum mechanics tell an atomistic spacetime?
The canonical answer to the question posed is "Yes." -- tacitly assuming that
quantum theory and the concept of spacetime are to be unified by `quantizing' a
theory of gravitation. Yet, instead, one may ponder: Could quantum mechanics
arise as a coarse-grained reflection of the atomistic nature of spacetime? --
We speculate that this may indeed be the case. We recall the similarity between
evolution of classical and quantum mechanical ensembles, according to Liouville
and von Neumann equation, respectively. The classical and quantum mechanical
equations are indistinguishable for objects which are free or subject to
spatially constant but possibly time dependent, or harmonic forces, if
represented appropriately. This result suggests a way to incorporate anharmonic
interactions, including fluctuations which are tentatively related to the
underlying discreteness of spacetime. Being linear and local at the quantum
mechanical level, the model offers a decoherence and natural localization
mechanism. However, the relation to primordial deterministic degrees of freedom
is nonlocal.Comment: Based on invited talks at Fourth International Workshop DICE2008,
held at Castello Pasquini / Castiglioncello, Italy, 22-26 September 2008 and
at DISCRETE'08 - Symposium on Prospects in the Physics of Discrete
Symmetries, held at IFIC, Valencia, Spain, 11-16 December 2008 - to appear in
respective volumes of Journal of Physics: Conference Serie
General massive gauge theory
The concept of perturbative gauge invariance formulated exclusively by means
of asymptotic fields is used to construct massive gauge theories. We consider
the interactions of massive and massless gauge fields together with
fermionic ghost and anti-ghost fields. First order gauge invariance
requires the introduction of unphysical scalars (Goldstone bosons) and fixes
their trilinear couplings. At second order additional physical scalars (Higgs
fields) are necessary, their coupling is further restricted at third order. In
case of one physical scalar all couplings are determined by gauge invariance,
including the Higgs potential. For three massive and one massless gauge field
the electroweak theory comes out as the unique solution.Comment: 20 pages, latex, no figure
Brane-induced Skyrmion on S^3: baryonic matter in holographic QCD
We study baryonic matter in holographic QCD with D4/D8/\bar{D8} multi-D brane
system in type IIA superstring theory. The baryon is described as the
"brane-induced Skyrmion", which is a topologically non-trivial chiral soliton
in the four-dimensional meson effective action induced by holographic QCD. We
employ the "truncated-resonance model" approach for the baryon analysis,
including pion and \rho meson fields below the ultraviolet cutoff scale M_KK
\sim 1GeV, to keep the holographic duality with QCD. We describe the baryonic
matter in large N_c as single brane-induced Skyrmion on the three-dimensional
closed manifold S^3 with finite radius R. The interactions between baryons are
simulated by the curvature of the closed manifold S^3, and the decrease of the
size of S^3 represents the increase of the total baryon-number density in the
medium in this modeling. We investigate the energy density, the field
configuration, the mass and the root-mean-square radius of single baryon on S^3
as the function of its radius R. We find a new picture of "pion dominance" near
the critical density in the baryonic matter, where all the (axial) vector meson
fields disappear and only the pion field survive. We also find the "swelling"
phenomena of the baryons as the precursor of the deconfinement, and propose the
mechanism of the swelling in general context of QCD. The properties of the
deconfinement and the chiral symmetry restoration in the baryonic matter are
examined by taking the proper order parameters. We also compare our
truncated-resonance model with another "instanton" description of the baryon in
holographic QCD, considering the role of cutoff scale M_KK.Comment: 25 pages, 12 figure
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