Abstract

This work is a step towards merging the ideas that arise from semi-classical methods in continuum QFT with analytic/numerical lattice field theory. In this context, we consider Yang-Mills theories coupled to fermions transforming in the adjoint representation of the gauge group. These theories have the remarkable property that confinement and discrete chiral symmetry breaking can persist at weak coupling on ℝ3 × S1 up to small (non-thermal) compactification radii. This work presents a lattice investigation of a gauge theory coupled to a single adjoint Majorana fermion, the mathcal{N}=1 Supersymmetric Yang-Mills theory (SYM), and opens the prospect to understand analytically a number of non-perturbative phenomena, such as confinement, mass gap, chiral and center symmetry realizations, both on the lattice and in the continuum. We study the compactification of mathcal{N}=1 SYM on the lattice with periodic and thermal boundary conditions applied to the fermion field. We provide numerical evidences for the conjectured absence of phase transitions with periodic boundary conditions for sufficiently light lattice fermions (stability of center-symmetry), for the suppression of the chiral transition, and we provide also a diagnostic for Abelian vs. non-Abelian confinement, based on per-site Polyakov loop eigenvalue distribution functions. We identify the role of the lattice artefacts that become relevant in the very small radius regime, and we resolve some puzzles in the naive comparison between continuum and lattice.

Highlights

  • Mechanism, and the other is that in theories with exactly massless fermions, the Polyakov mechanism would not work [2]

  • This work presents a lattice investigation of a gauge theory coupled to a single adjoint Majorana fermion, the N = 1 Supersymmetric Yang-Mills theory (SYM), and opens the prospect to understand analytically a number of non-perturbative phenomena, such as confinement, mass gap, chiral and center symmetry realizations, both on the lattice and in the continuum

  • We provide numerical evidences for the conjectured absence of phase transitions with periodic boundary conditions for sufficiently light lattice fermions, for the suppression of the chiral transition, and we provide a diagnostic for Abelian vs. non-Abelian confinement, based on per-site Polyakov loop eigenvalue distribution functions

Read more

Summary

Adjoint QCD on the lattice

QCD(adj) consists of a non-Abelian gauge-field Acμ(x) minimally coupled to Nf Majorana fermions λci (x). In numerical simulations the lattice extend is finite in all directions. If fermions fields fulfill anti-periodic boundary conditions in the S1 direction, the theory on the T 3 × S1 torus emulates the thermal partition function of a quantum field theory in a box. If periodic boundary conditions are applied to fermion fields on S1 direction, the theory on T 3 × S1 corresponds to the twisted partition function (1.1) with no thermal interpretation. The latter setup is useful to realize the notion of adiabatic continuity. The continuum limit and the massless limit must be extrapolated from the numerical data

Order parameters for the phase diagram of adjoint QCD
NcV3 x
The perturbative effective potential for the Polyakov loop on the lattice
Different Polyakov line effective actions
The phase diagram on the continuum and lattice
Explanation of the discrepancy of lattice and continuum
Numerical results for compactified adjoint QCD
Confined and deconfined phases in SYM theory
The Polyakov loop in the adjoint representation
The chiral condensate
Conclusions
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call