304 research outputs found
Matter-Antimatter Coexistence Method for Finite Density QCD
We propose a "matter-antimatter coexistence method" for finite-density
lattice QCD, aiming at a possible solution of the sign problem. In this method,
we consider matter and anti-matter systems on two parallel -sheets
in five-dimensional Euclidean space-time. For the matter system with a
chemical potential on a -sheet, we also prepare
the anti-matter system with on the other -sheet
shifted in the fifth direction. In the lattice QCD formalism, we introduce a
correlation term between the gauge variables in
and in , such as with a real parameter . In the limit of , a strong constraint is
realized, and the total fermionic determinant is real and non-negative. In the
limit of , this system goes to two separated ordinary
QCD systems with the chemical potential of and . On a
finite-volume lattice, if one takes an enough large value of , is realized and there occurs a phase cancellation
approximately between two fermionic determinants in and , which is
expected to suppress the sign problem and to make the lattice calculation
possible. For the obtained gauge configurations of the coexistence system,
matter-side quantities are evaluated through their measurement only for the
matter part . By the calculations with gradually decreasing and
their extrapolation to , physical quantities in finite density QCD
are expected to be estimated.Comment: 6 pages, 1 figure. arXiv admin note: substantial text overlap with
arXiv:1705.0751
Matter-antimatter coexistence method for finite density QCD toward a solution of the sign problem
Toward the lattice QCD calculation at finite density, we propose
"matter-antimatter coexistence method", where matter and anti-matter systems
are prepared on two parallel -sheets in five-dimensional Euclidean
space-time. We put a matter system with a chemical potential on a -sheet, and also put an anti-matter system with
on the other -sheet shifted in the fifth direction. Between
the gauge variables in and in , we introduce a correlation term with a real
parameter . In one limit of , a strong
constraint is realized, and therefore the total
fermionic determinant becomes real and non-negative, due to the cancellation of
the phase factors in and , although this system resembles QCD with
an isospin chemical potential. In another limit of ,
this system goes to two separated ordinary QCD systems with the chemical
potential of and . For a given finite-volume lattice, if one
takes an enough large value of , is
realized and phase cancellation approximately occurs between two fermionic
determinants in and , which suppresses the sign problem and is
expected to make the lattice calculation possible. For the obtained gauge
configurations of the coexistence system, matter-side quantities are evaluated
through their measurement only for the matter part . The physical quantities
in finite density QCD are expected to be estimated by the calculations with
gradually decreasing and the extrapolation to . We also
consider more sophisticated improvement of this method using an irrelevant-type
correlation.Comment: 4 page
Thermal Width Broadening of the 0++ Glueball Spectrum near Tc
We study the 0++ glueball correlator constructed with SU(3) anisotropic
quenched lattice QCD at various temperature taking into account the possible
existence of the thermal width in the ground-state peak. For this purpose, we
adopt the Breit-Wigner ansatz, analysing the lattice data obtained with
5,500-9,900 gauge configurations at each T. The results indicate the
significant thermal width broadening as Gamma(Tc) \sim 300 MeV with a reduction
in the peak center as Delta omega_0(Tc) \sim 100 MeV in the vicinity of the
critical temperature Tc.Comment: Talk given at Tokyo-Adelaide Joint Workshop on Quarks, Astrophysics
and Space Physics, Tokyo, Japan, 6-10 January 2003, 5 pages, Latex2e, 2
figure
Glueball properties in anisotropic SU(3) lattice QCD with improved action
We study the glueballs properties at finite temperature using SU(3) lattice
QCD at the quenched level with the anisotropic lattice. We use the tree-level
Symanzik O(a^2) improved action. We present our preliminary results which shows
the slight reduction of the scalar glueball mass near T_cComment: 8 pages, 13 figures, Talk given at Joint Workshop of the Special
Research Center for the Subatomic Structure of Matter and the National
Institute for Theoretical Physics (Workshop on Lepton Scattering, Hadrons and
QCD), Adelaide, Australia 26 March - 6 April 200
Three-quark potential and Abelian dominance of confinement in SU(3) QCD
We study the baryonic three-quark (3Q) potential and its Abelian projection
in terms of the dual-superconductor picture in SU(3) quenched lattice QCD. The
non-Abelian SU(3) gauge theory is projected onto Abelian U(1) gauge theory
in the maximal Abelian gauge. We investigate the 3Q potential and its Abelian
part for more than 300 different patterns of static 3Q systems in total at
on and at on with 1000-2000 gauge
configurations. For all the distances, both the 3Q potential and Abelian part
are found to be well described by the Y ansatz, i.e., two-body Coulomb term
plus three-body Y-type linear term ,
where is the minimum flux-tube length connecting the three
quarks. We find equivalence between the three-body string tension
and its Abelian part
with an accuracy within a few percent deviation, i.e., , which means Abelian dominance of the
quark-confining force in 3Q systems.Comment: 7pages, 7figures, 3tables; published versio
Quark motional effects on the interquark potential in baryons
We study the heavy-heavy-light quark () system in a non-relativistic
potential model, and investigate the quark motional effect on the
inter-two-quark potential in baryons. We adopt the Hamiltonian with the static
three-quark potential which is obtained by the first-principle calculation of
lattice QCD, rather than the two-body force in ordinary quark models. Using the
renormalization-group inspired variational method in discretized space, we
calculate the ground-state energy of systems and the light-quark spatial
distribution. We find that the effective string tension between the two heavy
quarks is reduced compared to the static three-quark case. This reduction of
the effective string tension originates from the geometrical difference between
the inter-quark distance and the flux-tube length, and is conjectured to be a
general property for baryons.Comment: 7 pages, 6 figure
- …