2,730 research outputs found
Framework for non-perturbative analysis of a Z(3)-symmetric effective theory of finite temperature QCD
We study a three dimensional Z(3)-symmetric effective theory of high
temperature QCD. The exact lattice-continuum relations, needed in order to
perform lattice simulations with physical parameters, are computed to order
O(a^0) in lattice perturbation theory. Lattice simulations are performed to
determine the phase structure of a subset of the parameter space.Comment: 28 pages, 11 figures; v3: references rearranged, typos corrected,
figs changed, published versio
Lattice analysis for the energy scale of QCD phenomena
We formulate a new framework in lattice QCD to study the relevant energy
scale of QCD phenomena. By considering the Fourier transformation of link
variable, we can investigate the intrinsic energy scale of a physical quantity
nonperturbatively. This framework is broadly available for all lattice QCD
calculations. We apply this framework for the quark-antiquark potential and
meson masses in quenched lattice QCD. The gluonic energy scale relevant for the
confinement is found to be less than 1 GeV in the Landau or Coulomb gauge.Comment: 4 pages, 4 figure
Classes of confining gauge field configurations
We present a numerical method to compute path integrals in effective SU(2)
Yang-Mills theories. The basic idea is to approximate the Yang-Mills path
integral by summing over all gauge field configurations, which can be
represented as a linear superposition of a small number of localized building
blocks. With a suitable choice of building blocks many essential features of
SU(2) Yang-Mills theory can be reproduced, particularly confinement. The
analysis of our results leads to the conclusion that topological charge as well
as extended structures are essential elements of confining gauge field
configurations.Comment: 18 pages, 16 figures, several sections adde
Cyclostationary shot noise in mesoscopic measurements
We discuss theoretically a setup where a time-dependent current consisting of
a DC bias and two sinusoidal harmonics is driven through a sample. If the
sample exhibits current-dependent shot noise, the down-converted noise power
spectrum varies depending on the local-oscillator phase of the mixer. The
theory of this phase-dependent noise is applied to discuss the measurement of
the radio-frequency single-electron transistor. We also show that this effect
can be used to measure the shot noise accurately even in nonlinear
high-impedance samples.Comment: 3 pages, 2 figure
2014 Fed Challenge Script: Current State of the Economy
Good afternoon everyone and thank you for having us here today. Though the recession began in 2007 and officially ended in 2009, recovery has been painfully slow. GDP growth has been insufficient to close the output gap, there continues to be slack in the labor market and inflation has stabilized below the Federal Reserve percent target. We are not meeting our dual mandate of full employment and stable prices even 6 years after the end of the recession. Despite some signs of strengthening in the economy during the past year, we do not believe that economy is on a self-sustaining path of recovery. Furthermore, the monetary policy actions taken by the Fed thus far to pull us out of the Great Recession have been insufficient. We propose a substantial strengthening of the our forward guidance; specifically, a commitment not to raise the federal funds rate until nominal GDP has returned to a path that we consider consistent with the dual mandate. [excerpt
Off-diagonal Gluon Mass Generation and Infrared Abelian Dominance in Maximally Abelian Gauge in SU(3) Lattice QCD
In SU(3) lattice QCD formalism, we propose a method to extract gauge fields
from link-variables analytically. With this method, we perform the first study
on effective mass generation of off-diagonal gluons and infrared Abelian
dominance in the maximally Abelian (MA) gauge in the SU(3) case. Using SU(3)
lattice QCD, we investigate the propagator and the effective mass of the gluon
fields in the MA gauge with U(1)_3 \timesU(1)_8 Landau gauge fixing. The
Monte Carlo simulation is performed on at =5.7, 5.8 and 6.0 at
the quenched level. The off-diagonal gluons behave as massive vector bosons
with the approximate effective mass in the region of fm, and the propagation is
limited within a short range, while the propagation of diagonal gluons remains
even in a large range. In this way, infrared Abelian dominance is shown in
terms of short-range propagation of off-diagonal gluons. Furthermore, we
investigate the functional form of the off-diagonal gluon propagator. The
functional form is well described by the four-dimensional Euclidean Yukawa-type
function with
for fm. This also indicates that the spectral function of
off-diagonal gluons has the negative-value region
Cold atoms in non-Abelian gauge potentials: From the Hofstadter "moth" to lattice gauge theory
We demonstrate how to create artificial external non-Abelian gauge potentials
acting on cold atoms in optical lattices. The method employs internal
states of atoms and laser assisted state sensitive tunneling. Thus, dynamics
are communicated by unitary -matrices. By experimental control of
the tunneling parameters, the system can be made truly non-Abelian. We show
that single particle dynamics in the case of intense U(2) vector potentials
lead to a generalized Hofstadter butterfly spectrum which shows a complex
``moth''-like structure. We discuss the possibility to employ non-Abelian
interferometry (Aharonov-Bohm effect) and address methods to realize matter
dynamics in specific classes of lattice gauge fields.Comment: 5 pages, 3 figure
Measure of the path integral in lattice gauge theory
We show how to construct the measure of the path integral in lattice gauge
theory. This measure contains a factor beyond the standard Haar measure. Such
factor becomes relevant for the calculation of a single transition amplitude
(in contrast to the calculation of ratios of amplitudes). Single amplitudes are
required for computation of the partition function and the free energy. For
U(1) lattice gauge theory, we present a numerical simulation of the transition
amplitude comparing the path integral with the evolution in terms of the
Hamiltonian, showing good agreement.Comment: 5 pages, 2 figure
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