Anomalous Fermion Number Non-Conservation on the Lattice

The anomaly for the fermion number current is calculated on the lattice in a simple prototype model with an even number of fermion doublets.Comment: 6 pages, CERN-TH.6717/92. Contribution to the Amsterdam Lattice '92 Conferenc

On the 1-loop lattice perturbation theory of the supersymmetric Ward identities

The one loop corrections to the supersymmetric Ward identities (WIs) in the discretized N=1 SU(2) supersymmetric Yang-Mills theory can be investigated by means of lattice perturbation theory. The supersymmetry (SUSY) is explicitly broken by the lattice discretization as well as by the introduction of Wilson fermions. However, the renormalization of the supercurrent can be carried out in a scheme that restores the nominal continuum WIs. We present our work in progress which is concerned with the 1-loop renormalization of the local supercurrent, i.e. with the perturbative computation of the corresponding renormalization constants and mixing coefficients.Comment: Lattice 2000 (Supersymmetry), 4 pges, 2 figure

Quantum fields on a lattice

This book presents a comprehensive and coherent account of the theory of quantum fields on a lattice, an essential technique for the study of the strong and the electroweak interactions of elementary particles. Quantum field theory describes basic physical phenomena over an extremely wide range of length or energy scales. Quantum fields exist in space and time, which can be approximated by a set of lattice points. This approximation allows the application of powerful analytical and numerical techniques, and has provided a powerful tool for the study of both the strong and the electroweak interaction. After introductory chapters on scalar fields, gauge fields and fermion fields, the book studies quarks and gluons in QCD and fermions and bosons in the electroweak theory. The last chapter is devoted to numerical simulation algorithms which have been used in recent large-scale numerical simulations

Diquark condensation in dense adjoint matter

We study SU(2) lattice gauge theory at non-zero chemical potential with one staggered quark flavor in the adjoint representation. In this model the fermion determinant, although real, can be both positive and negative. We have performed numerical simulations using both hybrid Monte Carlo and two-step multibosonic algorithms, the latter being capable of exploring sectors with either determinant sign. We find that the positive determinant sector behaves like a two-flavor theory, with the chiral condensate rotating into a two-flavor diquark condensate for mu>m_pi/2, implying a superfluid ground state. Good agreement is found with analytical predictions made using chiral perturbation theory. In the `full' model there is no sign of either onset of baryon density or diquark condensation for the range of chemical potentials we have considered. The impact of the sign problem has prevented us from exploring the true onset transition and the mode of diquark condensation, if any, for this model

Numerical simulations of dynamical gluinos in SU(3) Yang-Mills theory: first results

In a numerical Monte Carlo simulation of SU(3) Yang-Mills theory with dynamical gluinos we have investigated the behaviour of the expectation value of the scalar and pseudoscalar gluino condensates in order to determine the phase structure. Preliminary results are presented as a function of the hopping parameter