Jesse Carlsson

SU(N) glueball masses in (2+1)-dimensions

We calculate the masses of the lowest lying eigenstates of improved SU(2), SU(3), SU(4) and SU(5) Hamiltonian lattice gauge theory (LGT) in 2+1 dimensions using an analytic variational approach. The ground state is approximated by a one plaquette trial state and mass gaps are calculated in the symmetric and antisymmetric sectors by minimising over a suitable basis of rectangular states. Analytic techniques are developed to handle the group integrals arising in the calculation.

Direct Improvement of Hamiltonian Lattice Gauge Theory

We demonstrate that a direct approach to improving Hamiltonian lattice gauge theory is possible. Our approach is to correct errors in the Kogut-Susskind Hamiltonian by incorporating additional gauge invariant terms. The coefficients of these terms are chosen so that the order

SU(N) for large N in the Hamiltonian formalism in 2+1 dimensions

{a}^{2}

An Analytic Variational Study of the Mass Spectrum in 2+1 Dimensional SU(3) Hamiltonian Lattice Gauge Theory

classical errors vanish. We conclude with a brief discussion of tadpole improvement in Hamiltonian lattice gauge theory.

Improved Hamiltonian lattice gauge theory

Abstract We describe how to obtain improved Hamiltonians for pure glue SU(N) gauge theory, and how to analytically estimate the excited state energies in 2+1 dimensions for any N . We find that the N → ∞ excited states appear to follow a 2 dimensional harmonic oscillator spectrum.

Improved lattice Hamiltonians

We calculate the masses of the lowest lying eigenstates of improved SU(2) and SU(3) lattice gauge theory in 2+1 dimensions using an analytic variational approach. The ground state is approximated by a one plaquette trial state and mass gaps are calculated in the symmetric and antisymmetric sectors by minimising over a suitable basis of rectangular states.

Integrals over SU(N)

Abstract We derive an improved lattice Hamiltonian for pure gauge theory, coupling arbitrarily distant links in the kinetic term. The level of improvement achieved is examined in variational calculations of the SU(2) specific heat in 2+1 dimensions.

Harmonic oscillator spectrum for glueball states in 2 + 1 dimensions in the large N limit

Abstract Since the inception of lattice gauge theory much effort has been devoted to constructing improved actions. This has enabled calculations with relatively large lattice spacing a to be performed. In contrast, attempts to improve the Hamiltonian formulation of lattice gauge theory have only recently begun. Using the transfer matrix method or a Legendre transformation, improved Hamiltonians have been derived from improved actions. Here we present an alternative method. We demonstrate that direct classical improvement of the Hamiltonian is possible by modifying the electric field on the lattice. Improvement is achieved by fixing the electric field so that no O ( a 2 ) corrections appear in the kinetic Hamiltonian.