7,916 research outputs found
Brown-Rho Scaling in the Strong Coupling Lattice QCD
We examine the Brown-Rho scaling for meson masses in the strong coupling
limit of lattice QCD with one species of staggered fermion. Analytical
expression of meson masses is derived at finite temperature and chemical
potential. We find that meson masses are approximately proportional to the
equilibrium value of the chiral condensate, which evolves as a function of
temperature and chemical potential.Comment: Prepared for Chiral Symmetry in Hadron and Nuclear Physics
(Chiral07), Nov. 13-16, 2007, Osaka, Japa
Phase structure and chiral limit of compact lattice QED with Wilson fermions
We study the phase structure and chiral limit of compact lattice QED
with Wilson fermions (both dynamical and quenched). We use the standard Wilson
action (WA) and also the modified action (MA) with some lattice artifacts
suppressed. We show that lattice artifacts influence the distributions of
eigenvalues of the fermionic matrix especially for small values
of . Our main conclusion is that the chiral limit of compact QED
can be efficiently located using different techniques. Sorry, figures are not
included and can be sent by ordinary mail or Fax.Comment: TALK GIVEN AT THE LATTICE '93 INTERNATIONAL SYMPOSIUM LATTICE FIELD
THEORY, DALLAS, USA, OCTOBER 12--16, 1993 3 page
Lattice supersymmetry in 1D with two supercharges
A consistent formulation of a fully supersymmetric theory on the lattice has
been a long standing challenge. In recent years there has been a renewed
interest on this problem with different approaches. At the basis of the
formulation we present in the following there is the Dirac-Kahler twisting
procedure, which was proposed in the continuum for a number of theories,
including N=4 SUSY in four dimensions. Following the formalism developed in
recent papers, an exact supersymmetric theory with two supercharges on a one
dimensional lattice is realized using a matrix-based model. The matrix
structure is obtained from the shift and clock matrices used in two dimensional
non-commutative field theories. The matrix structure reproduces on a one
dimensional lattice the expected modified Leibniz rule. Recent claims of
inconsistency of the formalism are discussed and shown not to be relevant.Comment: 14 pages, Presented by SA and AD at the XXV International Symposium
on Lattice Field Theory, July 30 - August 4 2007, Regensburg, German
Microscopic observation of superconducting fluctuations in -(BEDT-TTF)Cu[N(CN)]Br by C NMR spectroscopy
We performed C-NMR experiment and measured spin-lattice relaxation
rate divided by temperature near the superconducting (SC) transition
temperature in -(BEDT-TTF)Cu[N(CN)]Br (-Br
salt), and -(BEDT-TTF)Cu(NCS) (-NCS salt). We
observed the reduction of starting at the temperature higher than
in -Br salt. Microscopic observation of quasi-particle density of
states in the fluctuating SC state revealed the effects of short-range Cooper
pairs induced in the normal state to the quasi-particle density of states. We
also performed systematic measurements in the fields both parallel and
perpendicular to the conduction plane in -Br and -NCS salts,
and confirmed that the reduction of above is observed only
in -Br salt regardless of the external field orientation.Comment: Accepted for publication in PR
The origin of the phase separation in partially deuterated -(ET)Cu[N(CN)]Br studied by infrared magneto-optical imaging spectroscopy
The direct observation of the phase separation between the metallic and
insulating states of 75 %-deuterated -(ET)Cu[N(CN)]Br ()
using infrared magneto-optical imaging spectroscopy is reported, as well as the
associated temperature, cooling rate, and magnetic field dependencies of the
separation. The distribution of the center of spectral weight () of
did not change under any of the conditions in which data were taken and
was wider than that of the non-deuterated material. This result indicates that
the inhomogenity of the sample itself is important as part of the origin of the
metal - insulator phase separation.Comment: 4 pages, 3 figures, accepted for publication in Solid State Commu
N=2 Supersymmetric Model with Dirac-Kahler Fermions from Generalized Gauge Theory in Two Dimensions
We investigate the generalized gauge theory which has been proposed
previously and show that in two dimensions the instanton gauge fixing of the
generalized topological Yang-Mills action leads to a twisted N=2 supersymmetric
action. We have found that the R-symmetry of N=2 supersymmetry can be
identified with the flavour symmetry of Dirac-Kahler fermion formulation. Thus
the procedure of twist allows topological ghost fields to be interpreted as the
Dirac-Kahler matter fermions.Comment: 22 pages, LaTe
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