Lattice gauge theory on a parallel computer

Technical Report · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6854724

Flower, J W

The results of several numerical simulations of QCD by Monte Carlo lattice gauge theory are presented. Studying the mesonic potential on a 20/sup 4/ lattice, we conclude that asymptotic scaling does not hold over the range 6.1 less than or equal to ..beta.. less than or equal to 6.7, although we are not able to quantify the discrepancies. The effect of discrete rotational symmetry on physical parameters is examined and seems to modify the string tension by 15% at ..beta.. = 6.1, while at ..beta.. = 6.3 the change was less than 1%. The potential between three charges is studied and yields a string tension of .18 GeV/sup 2/, consistent with mesonic calculations and relativized potential models. Contributions to the potential from low-energy string vibrations appear small in the range x less than or equal to .5 fm. We perform energy density measurements in the color fields surrounding both mesons and baryons, which provide strong evidence in favor of the dual superconductor picture of confinement. It is also suggested that the confining strings in the baryon meet at a central point rather than joining the quarks pairwise. Several algorithms are explored in an attempt to develop simulation methods which are able to directly account for the currents generated by color sources. The extension of the Langevin equation to complex degrees of freedom is derived leading to a Fokker-Planck equation for a complex 'Probability distribution'. Using this technique we are then able to calculate energy densities in U(1) gauge theory at large charge separations. The extension of the method to non-Abelian theories comes up against an unresolved problem in segregation for certain types of observable. 145 refs., 36 figs.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• DOE Contract Number: FG03-85ER25009
• OSTI ID: 6854724
• Report Number(s): DOE/ER/25009-411; ON: DE87008771
• Country of Publication: United States
• Language: English

Related Subjects

645400* -- High Energy Physics-- Field Theory
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGORITHMS
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
FIELD THEORIES
LANGEVIN EQUATION
LATTICE FIELD THEORY
MATHEMATICAL LOGIC
MONTE CARLO METHOD
PARALLEL PROCESSING
POSTULATED PARTICLES
POTENTIALS
PROGRAMMING
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
QUARKS