Unnamed: 0 int64 0 41k | title stringlengths 4 274 | category stringlengths 5 18 | summary stringlengths 22 3.66k | theme stringclasses 8
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7,300 | How to Put a Heavier Higgs on the Lattice | hep-lat | Lattice work, exploring the Higgs mass triviality bound, seems to indicate
that a strongly interacting scalar sector in the minimal standard model cannot
exist while low energy QCD phenomenology seems to indicate that it could. We
attack this puzzle using the 1/N expansion and discover a simple criterion for
selecting ... | physics |
7,301 | Spectral Density Study of the SU(3) Deconfining Phase Transition | hep-lat | We present spectral density reweighting techniques adapted to the analysis of
a time series of data with a continuous range of allowed values. In a first
application we analyze action and Polyakov line data from a Monte Carlo
simulation on $L_t L^3 (L_t=2,4)$ lattices for the SU(3) deconfining phase
transition. We calc... | physics |
7,302 | Vectorized Cluster Search | hep-lat | Contrary to conventional wisdom, the construction of clusters on a lattice
can easily be vectorized, namely over each ``generation'' in a breadth first
search. This applies directly to, e.g., the {\it single cluster} variant of the
Swendsen-Wang algorithm. On a Cray Y-MP, total CPU time was reduced by a factor
3.5 -- 7... | physics |
7,303 | Multi-Grid Monte Carlo III. Two-Dimensional O(4)-Symmetric Nonlinear $σ$-Model | hep-lat | We study the dynamic critical behavior of the multi-grid Monte Carlo (MGMC)
algorithm with piecewise-constant interpolation applied to the two-dimensional
O(4)-symmetric nonlinear $\sigma$-model [= SU(2) principal chiral model], on
lattices up to $256 \times 256$. We find a dynamic critical exponent
$z_{int,{\cal M}^2}... | physics |
7,304 | Monte Carlo Simulations of Higgs-Fermion Systems | hep-lat | To gain understanding of the Higgs-fermion sector of the standard model, we
study the one-component $Z_2$ symmetric and the four-component O(4) symmetric
scalar models coupled to staggered fermions using the hybrid Monte Carlo
algorithm. We map out the phase diagrams, and show that the $Z_2$ model has a
tree level pert... | physics |
7,305 | A Study of Symmetry Restoration at Finite Temperature in the O(4) Model Using Anisotropic Lattices | hep-lat | Results of investigations of the O(4) spin model at finite temperature using
anisotropic lattices are presented. In both the large $N$ approximation and the
numerical simulations using the Wolff cluster algorithm we find that the ratio
of the symmetry restoration temperature $T_{\rm SR}$ to the Higgs mass $m_{\rm
H}$ i... | physics |
7,306 | Dynamic Critical Behaviour of Wolff's Algorithm for $RP^N$ $σ$-Models | hep-lat | We study the performance of a Wolff-type embedding algorithm for $RP^N$
$\sigma$-models. We find that the algorithm in which we update the embedded
Ising model \`a la Swendsen-Wang has critical slowing-down as $z_\chi \approx
1$. If instead we update the Ising spins with a perfect algorithm which at
every iteration pro... | physics |
7,307 | How to Put a Heavier Higgs on the Lattice | hep-lat | The cutoff dependence of the Scalar Sector of the Minimal Standard Model can
result in an increase of the existing triviality bound estimates of the Higgs
mass. We present a large $N$ calculation and some preliminary N=4 results that
suggest that the increase can be as large as 30%, resulting to a bound of about
850 G ... | physics |
7,308 | QCD Hadron Spectroscopy with Staggered Dynamical Quarks at $β= 5.6$ | hep-lat | We present preliminary results from the 1991 HEMCGC simulations with
staggered dynamical fermions on a $16^3 \times 32$ lattice at $\beta = 5.6$
with sea quark masses $am_q = 0.025$ and 0.01. The spectroscopy was done both
for staggered valence quarks with mass equal to the sea quark masses and for
Wilson valence quark... | physics |
7,309 | Path Integrals and Voronin's Theorem on the Universality of the Riemann Zeta Function | hep-lat | We explore a new approach to the path integral for a latticized quantum
theory. This talk is based on work with N. Khuri and H. Ren. | physics |
7,310 | On the Dynamics of Light Wilson Quarks | hep-lat | We describe recent results obtained as part of the High Energy Monte Carlo
Grand Challenge (HEMCGC) project concerning the behaviour of lattice QCD with
light dynamical Wilson quarks. We show that it is possible to reach regions of
parameter space with light pions $m_\pi\ll0.2/a$, but that the equilibration
time for su... | physics |
7,311 | Monte Carlo Calculation of the Surface Free Energy for the 2d 7-state Potts Model, and an Estimate for 4d SU(3) Gauge Theory | hep-lat | Using the recently proposed multicanonical ensemble, we perform Monte Carlo
simulation for the 2d 7-state Potts model and calculate its surface free energy
density (surface tension) to be $2 f^s = 0.0241 \pm 0.0010$. This is an order
of magnitude smaller than other estimates in the recent literature. Relying on
existin... | physics |
7,312 | Random Walks and the Correlation Length Critical Exponent in Scalar Quantum Field Theory | hep-lat | The distance scale for a quantum field theory is the correlation length
$\xi$, which diverges with exponent $\nu$ as the bare mass approaches a
critical value. If $t=m^{2}-m_{c}^{2}$, then $\xi=m_{P}^{-1} \sim t^{-\nu}$ as
$t \to 0$. The two-point function of a scalar field has a random walk
representation. The walk ta... | physics |
7,313 | Thermodynamics of Lattice QCD with 2 Light Dynamical (Staggered) Quark Flavours on a $16^3\times 8$ Lattice | hep-lat | Lattice QCD with 2 light staggered quark flavours is being simulated on a
$16^3\times8$ lattice to study the transition from hadronic matter to a quark
gluon plasma. We have completed runs at $m_q=0.0125$ and are extending this to
$m_q=0.00625$. We also examine the addition of a non-dynamical "strange" quark.
Thermodyn... | physics |
7,314 | Multicanonical Ensemble: A New Approach to Simulate First-order Phase Transitions | hep-lat | Relying on the recently proposed multicanonical algorithm, we present a
numerical simulation of the first order phase transition in the 2d 10-state
Potts model on lattices up to sizes $100\times100$. It is demonstrated that the
new algorithm $lacks$ an exponentially fast increase of the tunneling time
between metastabl... | physics |
7,315 | Multimagnetical Simulations | hep-lat | We modified the recently proposed multicanonical MC algorithm for the case of
a magnetic field driven order--order phase transition. We test this {\it
multimagnetic} Monte Carlo algorithm for the D=2 Ising model at $\beta=0.5$ and
simulate square lattices up to size $100 \times 100$. On these lattices with
periodic bou... | physics |
7,316 | A New Approach to Spin Glass Simulations | hep-lat | We present a recursive procedure to calculate the parameters of the recently
introduced multicanonical ensemble and explore the approach for spin glasses.
Temperature dependence of the energy, the entropy and other physical quantities
are easily calculable and we report results for the zero temperature limit. Our
data ... | physics |
7,317 | A Numerical Test of KPZ Scaling: Potts Models Coupled to Two-Dimensional Quantum Gravity | hep-lat | We perform Monte Carlo simulations using the Wolff cluster algorithm of the
q=2 (Ising), 3, 4 and q=10 Potts models on dynamical phi-cubed graphs of
spherical topology with up to 5000 nodes. We find that the measured critical
exponents are in reasonable agreement with those from the exact solution of the
Ising model an... | physics |
7,318 | Multiple Potts Models Coupled to Two-Dimensional Quantum Gravity | hep-lat | We perform Monte Carlo simulations using the Wolff cluster algorithm of {\it
multiple} $q=2,3,4$ state Potts models on dynamical phi-cubed graphs of
spherical topology in order to investigate the $c>1$ region of two-dimensional
quantum gravity. Contrary to naive expectation we find no obvious signs of
pathological beha... | physics |
7,319 | Critical Behavior of Dynamically Triangulated Quantum Gravity in Four Dimensions | hep-lat | We performed detailed study of the phase transition region in Four
Dimensional Simplicial Quantum Gravity, using the dynamical triangulation
approach. The phase transition between the Gravity and
Antigravity phases turned out to be asymmetrical, so that we observed the
scaling laws only when the Newton constant app... | physics |
7,320 | Microcanonical cluster algorithms | hep-lat | I propose a numerical simulation algorithm for statistical systems which
combines a microcanonical transfer of energy with global changes in clusters of
spins. The advantages of the cluster approach near a critical point augment the
speed increases associated with multi-spin coding in the microcanonical
approach. The m... | physics |
7,321 | Point-Split Lattice Operators for B Decays | hep-lat | The matrix element which determines the B meson decay constant can be
measured on the lattice using an effective field theory for heavy quarks.
Various discretizations of the heavy-light bilinears which appear in this and
other B decay matrix elements are possible. The heavy-light bilinear currently
used for the determ... | physics |
7,322 | Chiral Perturbation Theory for the Quenched Approximation of QCD | hep-lat | [This version is a minor revision of a previously submitted preprint. Only
references have been changed.] We describe a technique for constructing the
effective chiral theory for quenched QCD. The effective theory which results is
a lagrangian one, with a graded symmetry group which mixes Goldstone bosons and
fermions,... | physics |
7,323 | Hadron Spectrum in QCD with Valence Wilson Fermions and Dynamical Staggered Fermions at $6/g^2=5.6 | hep-lat | We present an analysis of hadronic spectroscopy for Wilson valence quarks
with dynamical staggered fermions at lattice coupling $6/g^2 = \beta=5.6$ at
sea quark mass $am_q=0.01$ and 0.025, and of Wilson valence quarks in quenched
approximation at $\beta=5.85$ and 5.95, both on $16^3 \times 32$ lattices. We
make compari... | physics |
7,324 | Spectrum of Relativistic Fermions in a 2d Doped Lattice | hep-lat | Motivated by some previous work on fermions on random lattices and by
suggestions that impurities could trigger parity breaking in 2d crystals, we
have analyzed the spectrum of the Dirac equation on a two dimensional square
lattice where sites have been removed randomly --- a doped lattice. We have
found that the syste... | physics |
7,325 | Influence of the Measure on Simplicial Quantum Gravity in Four Dimensions | hep-lat | We investigate the influence of the measure in the path integral for
Euclidean quantum gravity in four dimensions within the Regge calculus. The
action is bounded without additional terms by fixing the average lattice
spacing. We set the length scale by a parameter $\beta$ and consider a scale
invariant and a uniform m... | physics |
7,326 | Phenomenology with Wilson fermions using smeared sources | hep-lat | We investigate the use of two types of non-local (``smeared'') sources for
quark propagators in quenched lattice QCD at $\beta=6.0$ using Wilson fermions
at $\kappa=0.154$ and $0.155$. We present results for the hadron mass spectrum,
meson decay constants, quark masses, the chiral condensate and the quark
distribution ... | physics |
7,327 | Scalar and axial matrix elements of the nucleon: sea quark content | hep-lat | Sea quark contributions to the scalar density and the axial current matrix
elements of the nucleon are studied in lattice qcd with two flavours of
dynamical wilson fermions. the results are compared to trends in heavy quark
mass expansions, and contrasted with the numbers obtained using dynamical
staggered fermions. | physics |
7,328 | The Free Energy of Spherical Bubbles in Lattice SU(3) Gauge Theory | hep-lat | We study the coefficients of the expansion $F(R) = 1/3 c_3 R^3 + 1/2 c_2 R^2
+ c_1 R$ of the free energy of spherical bubbles at $T=T_c$ in pure glue QCD
using lattice Monte Carlo techniques. The coefficient $c_3$ vanishes at $T=T_c$
and our results suggest that the sign and the order of magnitude of $c_1$ is in
agreem... | physics |
7,329 | Multigrid Methods in Lattice Field Computations | hep-lat | The multigrid methodology is reviewed. By integrating numerical processes at
all scales of a problem, it seeks to perform various computational tasks at a
cost that rises as slowly as possible as a function of $n$, the number of
degrees of freedom in the problem. Current and potential benefits for lattice
field computa... | physics |
7,330 | Blockspin Cluster Algorithms for Quantum Spin Systems | hep-lat | Cluster algorithms are developed for simulating quantum spin systems like the
one- and two-dimensional Heisenberg ferro- and anti-ferromagnets. The
corresponding two- and three-dimensional classical spin models with four-spin
couplings are maped to blockspin models with two-blockspin interactions.
Clusters of blockspin... | physics |
7,331 | Acceptance Rates in Multigrid Monte Carlo | hep-lat | An approximation formula is derived for acceptance rates of nonlocal
Metropolis updates in simulations of lattice field theories. The predictions of
the formula agree quite well with Monte Carlo simulations of 2-dimensional Sine
Gordon, XY and phi**4 models. The results are consistent with the following
rule: For a cri... | physics |
7,332 | Scaling topological charge in the CP^3 spin model | hep-lat | The CP^3 spin model is simulated at large correlation lengths in two
dimensions. An overrelaxation algorithm is employed which yields reduced
critical slowing down with dynamical exponents z around unity. We compare our
results with recent multigrid data on the massgap m and the spin susceptibility
and confirm the abse... | physics |
7,333 | Chiral Invariance and Species Doublers in Generic Fermion Models on the Lattice | hep-lat | Discussions are made on the structures of chirally invariant lattice actions
without any restriction of hermiticity. With the help of the Ward-Takahashi
identity a general conclusion can be derived that there must be species
doublers in any chirally invariant model provided that the model is chosen as
well-regularized,... | physics |
7,334 | Non--perturbative bounds on the Higgs mass in the minimal standard model | hep-lat | This is a slightly extended version of the talk delivered at the Topical
Workshop ``Non perturbative aspects of chiral gauge theories'', Accademia
Nazionale dei Lincei, Roma, 9-11 March, 1992. Abstract: The Higgs mass in the
minimal standard model is bounded by triviality and vacuum stability in the
range 50--100 $GeV$... | physics |
7,335 | Spontaneous symmetry breaking on the lattice generated by Yukawa interaction | hep-lat | We study by numerical simulation a lattice Yukawa model with naive fermions
at intermediate values of the Yukawa coupling $y$ when the nearest neighbour
coupling $\kp$ of the scalar field $\Phi$ is very weakly ferromagnetic ($\kp
\approx 0$) or even antiferromagnetic ($\kappa < 0$) and the nonvanishing value
of $\vev$ ... | physics |
7,336 | Wolff-Type Embedding Algorithms for General Nonlinear $σ$-Models | hep-lat | We study a class of Monte Carlo algorithms for the nonlinear $\sigma$-model,
based on a Wolff-type embedding of Ising spins into the target manifold $M$. We
argue heuristically that, at least for an asymptotically free model, such an
algorithm can have dynamic critical exponent $z \ll 2$ only if the embedding is
based ... | physics |
7,337 | Improved Nonrelativistic QCD for Heavy Quark Physics | hep-lat | We construct an improved version of nonrelativistic QCD for use in lattice
simulations of heavy quark physics, with the goal of reducing systematic errors
from all sources to below 10\%. We develop power counting rules to assess the
importance of the various operators in the action and compute all leading order
correct... | physics |
7,338 | Dynamics of Langevin Simulation | hep-lat | This chapter [of a supplement to Prog. Theo. Phys.] reviews numerical
simulations of quantum field theories based on stochastic quantization and the
Langevin equation. The topics discussed include renormalization of finite
step-size algorithms, Fourier acceleration, and the relation of the Langevin
equation to hybrid s... | physics |
7,339 | Ising Model Coupled to Three-Dimensional Quantum Gravity | hep-lat | We have performed Monte Carlo simulations of the Ising model coupled to
three-dimensional quantum gravity based on a summation over dynamical
triangulations. These were done both in the microcanonical ensemble, with the
number of points in the triangulation and the number of Ising spins fixed, and
in the grand canoncal... | physics |
7,340 | The Running Coupling from Lattice Gauge Theory | hep-lat | From an accurate determination of the inter-quark potential, one can study
the running coupling constant for a range of $R$-values and hence estimate the
scale $\Lambda_{\msbar} $. Detailed results are presented for $SU(2)$ pure
gauge theory to illustrate the method. | physics |
7,341 | Tunneling and Energy Splitting in Ising Models | hep-lat | The energy splitting $E_{0a}$ in two and four dimensional Ising models is
measured in a cylindrical geometry on finite lattices. By comparing to exact
results in the two dimensional Ising model we demonstrate that $E_{0a}$ can be
extracted very reliably from Monte Carlo calculations in practice. In four
dimensions we c... | physics |
7,342 | Reflection positive formulation of chiral gauge theories on a lattice | hep-lat | Gauge invariant chiral theories satisfying the reflection positivity is
constructed on a lattice. This requires the introduction of "half gauge fields"
defined some time ago by Brydges, Fr\"{o}hlich, and Seiler \cite{BFS}. A
two-dimensional model is considered in some detail. | physics |
7,343 | Chiral Limit of Nucleon Lattice Electromagnetic Form Factors | hep-lat | We calculate electric and magnetic form factors of protons and neutrons in
quenched Monte Carlo lattice QCD on a $16^3\times 24$ lattice at $\beta = 6.0$
using Wilson fermions. We employ a method which characterizes one of the
nucleon fields as a fixed zero-momentum secondary source. Extrapolating the
overall data set ... | physics |
7,344 | Quenched Hadrons using Wilson and O(a)-Improved Fermion Actions at beta=6.2 | hep-lat | We present the first study of the light hadron spectrum and decay constants
for quenched QCD using an O(a)-improved nearest-neighbour Wilson fermion action
at \beta=6.2. We compare the results with those obtained using the standard
Wilson fermion action, on the same set of 18 gauge field configurations of a
24^3 times ... | physics |
7,345 | The Quantized $O(1,2)/O(2)\times Z_2$ Sigma Model Has No Continuum Limit in Four Dimensions. II. Lattice Simulation | hep-lat | A lattice formulation of the $O(1,2)/O(2)\times Z_2$ sigma model is
developed, based on the continuum theory presented in the preceding paper.
Special attention is given to choosing a lattice action (the ``geodesic''
action) that is appropriate for fields having noncompact curved configuration
spaces. A consistent cont... | physics |
7,346 | Critical mass in nonzero temperature QCD with staggered fermions | hep-lat | The behaviour of the chiral condensate in QCD is investigated by means of a
study of the distribution of the zeros of the partition function in the complex
quark mass plane. Simulations are performed at fixed temperature on three
different spatial volumes at $\beta=5.04$ and at $\beta=4.9$ and $\beta=5.2$ on
a $4^4$ la... | physics |
7,347 | Parity breaking at high temperature and density | hep-lat | We investigate the question of parity breaking in three-dimensional Euclidean
SU(2) gauge-Higgs theory by Monte Carlo simulations. We observe no sign of
spontaneous parity breaking in the behaviour of both local and non-local gauge
invariant operators. However, the presence of parity odd terms in the action
can induce ... | physics |
7,348 | Mirror fermions in chiral gauge theories | hep-lat | Mirror fermions appear naturally in lattice formulations of the standard
model. The phenomenological limits on their existence and discovery limits at
future colliders are discussed. After an introduction of lattice actions for
chiral Yukawa-models, a recent numerical simulation is presented. In
particular, the emergin... | physics |
7,349 | Grand Canonical Partition Function of a 2-dimensional Hubbard Model | hep-lat | We present a new technique for a numerical analysis of the phase structure of
the 2D Hubbard model as a function of the hole chemical potential. The grand
canonical partition function for the model is obtained via Monte Carlo
simulations. The dependence of the hole occupation number on the chemical
potential and the te... | physics |
7,350 | Numerical Investigation of the Interface Tension in the three-dimensional Ising Model | hep-lat | The interface tension in the three-dimensional Ising model in the low
temperature phase is investigated by means of the Monte Carlo method. Together
with other physically relevant quantities it is obtained from a calculation of
time-slice correlation functions in a cylindrical geometry. The results at
three different v... | physics |
7,351 | Renormalization group and triviality in noncompact lattice QED with light fermions | hep-lat | In the framework of noncompact lattice QED with light fermions, we derive the
functional dependence of the average energy per plaquette on the bare
parameters using block-spin Renormalization Group arguments and assuming that
the renormalized coupling vanishes. Our numerical results for this quantity in
$8^4$ and $10^4... | physics |
7,352 | Lattice QCD with 8 Light Quark Flavors | hep-lat | QCD with eight flavors is studied on $16^3\times N_t$ lattices with $N_t=4$,
6, 8, 16 and 32, a dynamical quark mass $ma=0.015$ and lattice coupling
$\beta=6/g^2$ between 4.5 and 5.0. For $N_t=16$ and 32, hadron masses and
screening lengths are computed for a variety of valence quark masses. The
previously observed, st... | physics |
7,353 | Finite size effects and scaling in lattice CP(N-1) | hep-lat | We present model predictions for the spectrum of $CP^{N-1}$ in a periodic box
and use them to interpret the strong finite size effects observed in lattice
simulations at medium values of $N$. The asymptotic scaling behaviour of
alternative lattice actions is discussed along with some aspects of multigrid
algorithm effi... | physics |
7,354 | Resonance Scattering Phase Shifts in a 2-d Lattice Model | hep-lat | We study a simple 2-d model representing two fields with different mass and a
3-point coupling term. The phase shift in the resonating 2-particle channel is
determined from the energy spectrum obtained in Monte Carlo simulations on
finite lattices. Masses and wave function renormalization constants of the
fields as wel... | physics |
7,355 | Massless Decoupled Doublers: Chiral Yukawa Models and Chiral Gauge Theories | hep-lat | We present a new method for regularizing chiral theories on the lattice. The
arbitrariness in the regularization is used in order to decouple massless
replica fermions. A continuum limit with only one fermion is obtained in
perturbation theory and a Golterman-Petcher like symmetry related to the
decoupling of the repli... | physics |
7,356 | Gauge Fixing on the Lattice without Ambiguity | hep-lat | A new gauge fixing condition is discussed, which is (lattice) rotation
invariant, has the `smoothness' properties of the Landau gauge but can be
efficiently computed and is unambiguous for almost all lattice gauge field
configurations. | physics |
7,357 | Virtual Bond Percolation for Ising Cluster Dynamics | hep-lat | The Fortuin-Kasteleyn mapping between the Ising model and the site-bond
correlated percolation model is shown to be only one of an infinite class of
exact mappings. These new cluster representations are a result of
"renormalized" percolation rules correlated to entire blocks of spins. For
example these rules allow for ... | physics |
7,358 | Fermion-Higgs model with Reduced Staggered Fermions | hep-lat | We introduce a lattice fermion-Higgs model with one component `reduced
staggered' fermions. In order to use the fermion field as efficiently as
possible we couple the two {\em staggered} flavors to the O(4) Higgs field
leading to a model with only one SU(2) doublet in the scaling region. The
number of fermions is doubl... | physics |
7,359 | Hopping Parameter Expansion for Heavy-Light Systems | hep-lat | We present a technique which permits the calculation of two-point functions
of operators containing one heavy quark and an arbitrary number of light quarks
as analytic functions of the heavy-quark mass. It is based on the standard
Jacobi linear solver used for the calculation of quark propagators. Results for
the heavy... | physics |
7,360 | Absence of Chiral Fermions in the Eichten--Preskill Model | hep-lat | The model proposed by Eichten and Preskill for obtaining theories with chiral
fermions from the lattice is shown to undergo spontaneous symmetry breaking. In
addition, the fermions appear to be Dirac-like everywhere in the phase diagram
with no room for undoubled Weyl fermions. The phase diagram of a closely
related Hi... | physics |
7,361 | More about orbitally excited hadrons from lattice QCD | hep-lat | This is a second paper describing the calculation of spectroscopy for
orbitally excited states from lattice simulations of Quantum Chromodynamics.
New features include higher statistics for P-wave systems and first results for
the spectroscopy of D-wave mesons and baryons, for relatively heavy quark
masses. We paramete... | physics |
7,362 | An Effective Model for Crumpling in Two Dimensions? | hep-lat | We investigate the crumpling transition for a dynamically triangulated random
surface embedded in two dimensions using an effective model in which the
disordering effect of the $X$ variables on the correlations of the normals is
replaced by a long-range ``antiferromagnetic'' term. We compare the results
from a Monte Ca... | physics |
7,363 | The XY Model Coupled to Two-Dimensional Quantum Gravity | hep-lat | We perform Monte Carlo simulations using the Wolff cluster algorithm of the
XY model on both fixed and dynamical phi-cubed graphs (i.e. without and with
coupling to two-dimensional quantum gravity). We compare the numerical results
with the theoretical expectation that the phase transition remains of KT type
when the X... | physics |
7,364 | Numerical study of Yang-Mills classical solutions on the twisted torus | hep-lat | We use the lattice cooling method to investigate the structure of some gauge
fixed SU(2) Yang-Mills classical solutions of the euclidean equations of motion
which are defined in the 3-torus with symmetric twisted boundary conditions. | physics |
7,365 | Tunneling and the Spectrum of the Potts Model | hep-lat | The three-dimensional, three-state Potts model is studied as a paradigm for
high temperature quantum chromodynamics. In a high statistics numerical
simulation using a Swendson-Wang algorithm, we study cubic lattices of
dimension as large as $64^3$ and measure correlation functions on long lattices
of dimension $20^2\ti... | physics |
7,366 | London relation and fluxoid quantization for monopole currents in U(1) lattice gauge theory | hep-lat | We explore the analogy between quark confinement and the Meissner effect in
superconductors. We measure the response of color-magnetic "supercurrents" from
Dirac magnetic monopoles to the presence of a static quark-antiquark pair in
four dimensional U(1) lattice gauge theory. Our results indicate that in the
confined p... | physics |
7,367 | Low temperature expansion for the 3-d Ising Model | hep-lat | We compute the weak coupling expansion for the energy of the three
dimensional Ising model through 48 excited bonds. We also compute the
magnetization through 40 excited bonds. This was achieved via a recursive
enumeration of states of fixed energy on a set of finite lattices. We use a
linear combination of lattices wi... | physics |
7,368 | Properties of Interfaces in the two and three dimensional Ising Model | hep-lat | To investigate order-order interfaces, we perform multimagnetical Monte Carlo
simulations of the $2D$ and $3D$ Ising model. Following Binder we extract the
interfacial free energy from the infinite volume limit of the magnetic
probability density. Stringent tests of the numerical methods are performed by
reproducing wi... | physics |
7,369 | Lattice QCD Spectroscopy with an Improved Wilson Fermion Action | hep-lat | We study the hadronic spectrum in quenched lattice QCD using an improved
Wilson fermion action (Hamber-Wu(1983),Eguchi-Kawamoto(1984)) at $\beta= 5.7$
and $\beta =6.0$. We find a systematic reduction of the finite spacing effects
compared to the results obtained by using the standard Wilson action. | physics |
7,370 | The Four-Fermi Model in Three Dimensions at Non-Zero Density and Temperature | hep-lat | The Four Fermi model with discrete chiral symmetry is studied in three
dimensions at non-zero chemical potential and temperature using the Hybrid
Monte Carlo algorithm. The number of fermion flavors is chosen large $(N_f=12)$
to compare with analytic results. A first order chiral symmetry restoring
transition is found ... | physics |
7,371 | The Universlity Class of Monopole Condensation in Non-Compact, Quenched Lattice QED | hep-lat | Finite size scaling studies of monopole condensation in noncompact quenched
lattice $QED$ indicate an authentic second order phase transition lying in the
universality class of four dimensional percolation. Since the upper critical
dimension of percolation is six, the measured critical indices are far from
mean-field v... | physics |
7,372 | Gauge Dependence of Effective Quark Mass and Matrix Elements in Gaugefixed Large $N$ Strong Coupling Lattice QCD | hep-lat | In conjunction with recent numerical \hbox{$\lambda~\partial_0 A_0 +
\nabla\cdot\vec{A} =0$} ``$\lambda$-gauge'' results reported in a companion
paper, we construct an $N\to\infty$ Wilson loop picture of
$\lambda$-gaugefixing in which (I)the $\lambda$-gauge expectation value of a
link chain $C$ is the weighted sum over... | physics |
7,373 | Kinematics of Multigrid Monte Carlo | hep-lat | We study the kinematics of multigrid Monte Carlo algorithms by means of
acceptance rates for nonlocal Metropolis update proposals. An approximation
formula for acceptance rates is derived. We present a comparison of different
coarse-to-fine interpolation schemes in free field theory, where the formula is
exact. The pre... | physics |
7,374 | Fermions in Models with Wilson--Yukawa Couplings | hep-lat | Our work on models with Wilson--Yukawa couplings is reviewed. Conclusions
include the failure of such models to produce continuum chiral gauge theories. | physics |
7,375 | On the Eichten--Preskill Proposal for Lattice Chiral Gauge Theories | hep-lat | We have studied the Eichten--Preskill proposal for constructing lattice
chiral gauge theories using both strong and weak coupling methods. The results
indicate that this proposal is unlikely to work due to a dynamical behavior
similar to that of the Smit--Swift proposal, which also does not give rise to
chiral fermions... | physics |
7,376 | The Phase Diagram of a U(1) Higgs-Yukawa Model at Finite $λ$ | hep-lat | In this paper we investigate how the phase diagram of a U(1) symmetric
Higgs-Yukawa system depends on the scalar self coupling $\lambda$. The phase
diagram of similar models with continuous symmetry were extensively studied in
the infinite scalar self coupling $\lambda=\infty$ limit. Recent analytical and
numerical cal... | physics |
7,377 | Recent Results of Multimagnetical Simulations of the Ising Model | hep-lat | To investigate order-order interfaces, we perform multimagnetical Monte Carlo
simulations of the $2D$ and $3D$ Ising model. Stringent tests of the numerical
methods are performed by reproducing with high precision exact $2D$ results. In
the physically more interesting $3D$ case we estimate the amplitude $F^s_0$ of
the ... | physics |
7,378 | The Schrödinger Functional - a Renormalizable Probe for Non-Abelian Gauge Theories | hep-lat | Following Symanzik we argue that the Schr\"odinger functional in lattice
gauge theories without matter fields has a well-defined continuum limit. Due to
gauge invariance no extra counter terms are required. The Schr\"odinger
functional is, moreover, accessible to numerical simulations. It may hence be
used to study the... | physics |
7,379 | Computation of the Running Coupling in the SU(2) Yang-Mills Theory | hep-lat | A finite-size scaling technique is applied to the SU(2) gauge theory (without
matter fields) to compute a non-perturbatively defined running coupling
alpha(q) for a range of momenta q given in units of the string tension K. We
find that already at rather low q, the evolution of alpha(q) is well described
by the 2-loop ... | physics |
7,380 | A Proposal for Simulating Chiral Fermions | hep-lat | We describe a method for evaluating chiral gauge theories that is not plagued
by the doubling problem. To demonstrate the efficiency of the approach, we
apply our ideas to the chiral Schwinger model. | physics |
7,381 | The Topological Susceptibility of the Lattice CP(n-1) Model on the Torus and the Sphere | hep-lat | The topological vacuum structure of the two-dimensional $~CP^{n-1}~$ model
for $~n = 3,5,7~$ is studied on the lattice. In particular we investigate the
small-volume limit on the torus as well as on the sphere and compare with
continuum results. For $~n \ge 5~$ , where lattice artifacts should be
suppressed, the topolo... | physics |
7,382 | Lattice Charge Overlap: Towards the Elastic Limit | hep-lat | A numerical investigation of time-separated charge overlap measurements is
carried out for the pion in the context of lattice QCD using smeared Wilson
fermions. The evolution of the charge distribution function is examined and the
expected asymptotic time behavior $\sim e^{-(E_{q}-m_{\pi})t}$, where $t$
represents the ... | physics |
7,383 | Improving Multigrid and Conventional Relaxation Algorithms for Propagators | hep-lat | Practical modifications of deterministic multigrid and conventional
relaxation algorithms are discussed. New parameters need not be tuned but are
determined by the algorithms themselves. One modification can be thought of as
``updating on a last layer consisting of a single site''. It eliminates
critical slowing down i... | physics |
7,384 | The equivalence of the SU(N) Yang Mills Theory with a Purely Fermionic Model | hep-lat | We investigate the detailed conditions under which a purely fermionic model
with current-current interaction goes over to a renormalizable, asymptotically
free SU$(N)$ gauge theory. | physics |
7,385 | Fermion Interactions in the Wilson Yukawa Approach for Lattice Chiral Gauge Theories | hep-lat | We consider fermion-gauge couplings in the Wilson-Yukawa approach for lattice
chiral gauge theories. At the leading order of a fermionic hopping parameter
expansion we find that the fermion-gauge coupling has a chiral and tree-like
structure. We argue that this fermion-gauge coupling remains non-zero in the
continuum l... | physics |
7,386 | Topography of the hot sphaleron Transitions | hep-lat | By numerical simulations in {\it real time} we provide evidence in favour of
sphaleron like transitions in the hot, symmetric phase of the electroweak
theory. Earlier performed observations of a change in the Chern-Simons number
are supplemented with a measurement of the lowest eigenvalues of the
three-dimensional stag... | physics |
7,387 | Numerical simulation of heavy fermions in an SU(2)_L x SU(2)_R symmetric Yukawa model | hep-lat | An exploratory numerical study of the influence of heavy fermion doublets on
the mass of the Higgs boson is performed in the decoupling limit of a chiral
$\rm SU(2)_L \otimes SU(2)_R$ symmetric Yukawa model with mirror fermions. The
behaviour of fermion and boson masses is investigated at infinite bare quartic
coupling... | physics |
7,388 | Crossover Between Weakly and Strongly Self-avoiding Random Surfaces | hep-lat | We investigate the crossover between weak and strong self-avoidance in a
simulation of random surfaces with extrinsic curvature. We consider both
dynamically triangulated and rigid surfaces with the two possible
discretizations of the extrinsic curvature term. | physics |
7,389 | QCD thermodynamics with two flavors of Wilson quarks at N_t=6 | hep-lat | We report on a study of hadron thermodynamics with two flavors of Wilson
quarks on 12^3x6 lattices. We have studied the crossover between the high and
low temperature regimes for three values of the hopping parameter, kappa=0.16,
0.17, and 0.18. At each of these values of kappa we have carried out spectrum
calculations... | physics |
7,390 | A new approach to noncompact lattice qed with light fermions | hep-lat | We discuss detailed simulations of the non compact abelian model coupled to
light fermions, using a method previously developed that includes the effects
of the fermionic interactions in an effective action. The approximations
involved are related to an expansion in the flavour number. We address the
problem of the (no... | physics |
7,391 | Global Demons in Field Theory : Critical Slowing Down in the Xy Model | hep-lat | We investigate the use of global demons, a `canonical dynamics', as an
approach to simulating lattice regularized field theories. This
deterministically chaotic dynamics is non-local and non-Hamiltonian, and
preserves the canonical measure rather than $\delta(H-E)$. We apply this
inexact dynamics to the 2D XY model, co... | physics |
7,392 | Finite Size Scaling of Probability Distributions in SU(2) Lattice Gauge Theory and Phi^4 Field Theory | hep-lat | For a system near a second order phase transition, the probability
distribution for the order parameter can be given a finite size scaling form.
This fact is used to compare the finite temperature phase transition for the
Wilson lines in d=3+1 SU(2) lattice gauge theory with the phase transition in
d=3 phi^4 field theo... | physics |
7,393 | Topological susceptibility and string tension in the lattice CP(N) models | hep-lat | In the lattice CP(N) models we studied the problems related to the measure of
the topological susceptibility and the string tension . We perfomed numerical
simulations at N=4 and N=10. In order to test the universality, we adopted two
different lattice formulations. Scaling and universality tests led to the
conclusion ... | physics |
7,394 | A Lower Bound on $T_{SR}/{m_{\rm H}}$ in the O(4) Model on Anisotropic Lattices | hep-lat | Results of an investigation of the $O(4)$ spin model at finite temperature
using anisotropic lattices are presented. In both the large $N$ approximation
and numerical simulations using the Wolff cluster algorithm we find that the
ratio of the symmetry restoration temperature $T_{\rm SR}$ to the Higgs mass
$m_{\rm H}$ i... | physics |
7,395 | Chern-Simons term in the 4-dimensional SU(2) Higgs model | hep-lat | Using a variation of Lueschers geometric charge definition for SU(2) lattice
gauge theory, we have managed to give a geometric expression for it's
Chern-Simons ter. From this definition we have checked the periodic structure.
we determined the Chern-Simons density for symmetric and asymmetric lattices
near the critical... | physics |
7,396 | A Parallel Cluster Labeling Method for Monte Carlo Dynamics | hep-lat | We present an algorithm for cluster dynamics to efficiently simulate large
systems on MIMD parallel computers with large numbers of processors. The method
divides physical space into rectangular cells which are assigned to processors
and combines a serial local procedure with a nearest neighbor relaxation
process. By c... | physics |
7,397 | A Rigourous Treatment of the Lattice Renormalization Problem of F_B | hep-lat | The $B$-meson decay constant can be measured on the lattice using a $1/m_b$
expansion. To relate the physical quantity to Monte Carlo data one has to know
the renormalization coefficient, $Z$, between the lattice operators and their
continuum counterparts. We come back to this computation to resolve
discrepancies found... | physics |
7,398 | Comparison of Lattice Coulomb Gauge Wave Functions in Quenched Approximation and with Dynamical Fermions | hep-lat | We present a comparison of Coulomb gauge wave functions from $6/{g^2}=6.0$
quenched simulations with two simulations which include the effects of
dynamical fermions: simulations with two flavors of dynamical staggered quarks
and valence Wilson quarks at $6/{g^2}=5.6$ and simulations with two flavors of
dynamical Wilson... | physics |
7,399 | Continuum Gauge Fields from Lattice Gauge Fields | hep-lat | On the lattice some of the salient features of pure gauge theories and of
gauge theories with fermions in complex representations of the gauge group seem
to be lost. These features can be recovered by considering part of the theory
in the continuum. The prerequisite for that is the construction of continuum
gauge field... | physics |
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