13,363 research outputs found
Quantum chromodynamics with various number of flavors
The phase structure of QCD with various number of flavors is studied for
Wilson quarks. For the case of we find that the finite temperature
deconfining transition is of first order in the chiral limit on an
lattice. Together with our previous results that the deconfining transition in
the chiral limit is continuous for and is first order for , the
order of the transition is found to be consistent with a prediction of
universality. The case of QCD is also studied in the strong coupling
limit and the phase structure is found to be quite similar to the case of
: There exists a critical number of flavors and for the confinement is broken even in the strong coupling limit for light
quarks. corresponding to 7 for .Comment: 3 pages with 5 PS figures, LaTeX (espcrc2.sty required), UTHEP-26
Construction of staples in lattice gauge theory on a parallel computer
We propose a simple method to construct staples in lattice gauge theory with
Wilson action on a parallel computer. This method can be applicable to any
dimensional system and to any dimensional division without difficulty.
Furthermore this requires rather small working area to realize gauge simulation
on a parallel computer.Comment: 4 pages of A4 forma
Electromagnetic power absorber
A structure is presented with a surface portion of dielectric material which passes electromagnetic radiation and with a portion below the surface which includes material that absorbs the radiation, the face of the structure being formed with numerous steep ridges. The steepness of the dielectric material results in a high proportion of the electromagnetic energy passing through the surface for absorption by the absorbing material under the surface. A backing of aluminum or other highly heat-conductive and reflective material lies under the face and has very steep protuberances supporting the absorbing and dielectric materials
Phase structure of QCD for general number of flavors
We investigate and elucidate the phase structure of QCD for general number of
flavors with Wilson quarks, varying from 2 up to 300. Based on
numerical results combined with the result of the perturbation theory we
propose the following picture: When , there is only a trivial fixed
point and therefore the theory in the continuum limit is trivial. On the other
hand, when , there is a non-trivial fixed point and therefore
the theory is non-trivial with anomalous dimensions, however, without quark
confinement. Theories which satisfy both quark confinement and spontaneous
chiral symmetry breaking in the continuum limit exist only for . We
also discuss the structure of the deconfining phase at finite temperatures for
the small number of flavors such as and 3, through a systematic study
of it for general number of flavors.Comment: LaTeX, 7 pages, 10 PS figures, Talk presented at LATTICE96(poster)
and LATTICE96(finite temperature
Chiral Phase Transition in Lattice QCD with Wilson Quarks
The nature of the chiral phase transition in lattice QCD is studied for the
cases of 2, 3 and 6 flavors with degenerate Wilson quarks, mainly on a lattice
with the temporal direction extension . We find that the chiral phase
transition is continuous for the case of 2 flavors, while it is of first order
for 3 and 6 flavors.Comment: uuencoded compressed tar file, LaTeX, 14 pages, 7 figure
Finite-temperature chiral transitions in QCD with the Wilson quark action
We investigate the finite-temperature phase structure and the scaling of the
chiral condensate in lattice QCD with two degenerate light quarks, using a
renormalization group improved gauge action and the Wilson quark action. We
obtain a phase diagram which is consistent with that from the parity-flavor
breaking scenario. The scaling relation for the chiral condensate assuming the
critical exponents and the scaling function of the three dimensional O(4) model
is remarkably satisfied for a wide range of parameters. This indicates that the
chiral transition in two flavor QCD is of second order in the continuum limit.Comment: LaTeX, 3 pages, 4 EPS figures, Talk presented at LATTICE97 (finite
temperature
Transport Coefficients of Quark Gluon Plasma for Pure Gauge Models
The transport coefficients of quark gluon plasma are calculated on a lattice
16**3X8, with the pure gauge models. Matsubara Green's functions of energy
momentum tensors have very large fluctuations and about a few million MC sweeps
are needed to reduce the errors reasonably small in the case of the standard
action. They are much suppressed if Iwasaki's improved action is employed.
Preliminary results show that the transport coefficients roughly depend on the
coupling constant as a**(-3)(g) in the case of SU(2).Comment: Talk presented at LATTICE96(finite temperature), 3 pages in latex, 4
Postscript figure
Anisotropic Improved Gauge Actions; --Perturbative and Numerical Studies --
The parameter on the anisotropic lattice, the spatial and
temperature coupling constant , and their derivative
with respaect to the the anisotropy parameter are studied perturbatively
for the class of improved actions, which cover tree level Symanzik's, Iwasaki's
and QCDTARO's improved actions. The becomes less
than 1 for Iwasaki's and QCDTARO's action, which is confirmed nonperturbatively
by numerical simulations. Derivatives of the coupling constants with respect to
the anisotropy parameter, and , change sign for those improved actions.Comment: LATTICE98(hightemp), 3 pages in latex, 4 Postscript figures Fonts in
Fig3 is replaced Aria
QCD Phase Transition with Strange Quark in Wilson Formalism for Fermions
The nature of QCD phase transition is studied with massless up and down
quarks and a light strange quark, using the Wilson formalism for quarks on a
lattice with the temporal direction extension . We find that the phase
transition is first order in the cases of both about 150 MeV and 400 MeV for
the strange quark mass. These results together with those for three degenerate
quarks suggest that QCD phase transition in nature is first order.Comment: uuencoded compressed tar file, LaTeX, 13 pages, 9 figures, Minor
errors for quoting references are corrected and a reference is adde
Finite Temperature QCD with Wilson Quarks: A Study with a Renormalization Group Improved Gauge Action
Finite temperature transition in lattice QCD with degenerate Wilson quarks is
investigated on an lattice, using a renormalization group improved
gauge action. We find the following for the case:
1) The transition is smooth for a wide range of the quark mass.
2) The chiral transition is continuous.
3) The chiral condensation well satisfies a scaling relation with the
critical exponents of the 3 dimensional spin model. For , we find
that the chiral transition is of first order.Comment: 4 pages (6 figures), Postscript file, Contribution to Lattice 95
proceeding
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