53,555 research outputs found
Towards QCD thermodynamics using exact chiral symmetry on lattice
The thermodynamics of massless ideal gas of overlap quarks has been
investigated numerically for both zero and nonzero baryon chemical potential
. While the parameter M has been shown to be irrelevant in the continuum
limit, it is shown numerically that the continuum limit can be reached with
relatively coarser lattices for certain range of M. Numerical limitation of the
existing method of introduction of chemical potential in the overlap formalism
is discussed. We have also studied the energy density of free domain wall
fermions in the absence of and estimated the extent of lattice in the
fifth dimension for which the overlap results are recovered.
Interestingly, this value of is also minimum for the same range of M
found in the overlap case.Comment: 5 pages, 4 figures, to appear in the proceedings of the 20th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions:
Quark Matter 2008 (QM2008
Study of composites as substrate materials in large space telescopes
Nonmetallic composites such as the graphite/epoxy system were investigated as possible substrates for the primary mirror of the large space telescope. The possible use of fiber reinforced metal matrix composites was reviewed in the literature. Problems arising out of the use of composites as substrate materials such as grinding, polishing, adherence of reflective coatings, rigidity of substrate, hygrospcopici tendency of the composites, thermal and temporal stability and other related problems were examined
Anomaly at finite density and chiral fermions on lattice
Using both perturbation theory in the Euclidean formalism as well as the
non-perturbative Fujikawa's method, we verify that the chiral anomaly equation
remains unaffected in continuum QCD in the presence of nonzero chemical
potential, \mu. We extend our considerations to lattice fermions with exact
chiral symmetry and discuss the consequences for the recent Bloch-Wettig
proposal for the Dirac operator at finite chemical potential. We propose a new
simpler method of incorporating \mu.Comment: Talk presented at the XXVII International Symposium on Lattice Field
Theory, July 26-31, 2009, Peking University, Beijing, China; 7 pages, 3
figure
Thermodynamics of free Domain Wall fermions
Studying various thermodynamic quantities for the free domain wall fermions
for both finite and infinite fifth dimensional extent N_5, we find that the
lattice corrections are minimum for for both energy density and
susceptibility, for its irrelevant parameter M in the range 1.45-1.50. The
correction terms are, however, quite large for small lattice sizes of
. We propose modifications of the domain wall operator, as well as
the overlap operator, to reduce the finite cut-off effects to within 10% of the
continuum results of the thermodynamic quantities for the currently used
N_T=6-8 lattices. Incorporating chemical potential, we show that \mu^2
divergences are absent for a large class of such domain wall fermion actions
although the chiral symmetry is broken for .Comment: 11 pages, 15 figures include
On weak shock diffraction in real gases
Asymptotic solutions are obtained for the two-dimensional Euler system for
real gases with appropriate boundary conditions which describe the diffraction
of a weak shock at a right-angled wedge; the real gas effects are characterized
by a van der Waals type equation of state. The behavior of the flow
configuration influenced by the real gas effects, that includes the local
structure near a singular point, is studied in detail.Comment: 14 pages, 1 figure. arXiv admin note: substantial text overlap with
arXiv:1405.066
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