Confinement and Deconfinement in Gauge Theories : A Quantum Field Theory @DIASDublin

Uploaded September 2023 | Updated September 2026, 2 weeks ago

Speaker: A. P. Balachandran (Syracuse University)
Abstract: After a brief discussion of small and large gauge transformations and the nature of observables, we discuss superselection sectors in gauge theories. There are an infinity of them,
classified by large gauge transformations. Gauge theory sectors are labelled by the eigenvalues of a complete commuting set (CCS) of these transformations.
In QED, the standard chemical potential is one such operator generating global U(1). There are many more given by the moments of the electric field on the sphere at infinity. In QCD, the CCS
are constructed from the two commuting generators spanning a Cartan subalgebra.
We show that any element of a large gauge transformation can be added to the standard Hamiltonian as a chemical potential without changing field equations and that in QCD, they lead to
confined and deconfined phases . A speculation about the physical meaning of these chemical potentials is also made.

Confinement and Deconfinement in Gauge Theories : A Quantum Field Theory

$Maxwell Theory of Fractons Speaker: Erica Bertolini (DIAS) Abstract: In this talk I will show that the main properties of the fracton quasiparticles can be derived from a generalized covariant Maxwell-like action. Starting from a rank-2 symmetric tensor field, a partially symmetric rank-3 tensor field strength can be built, which obeys a kind of Bianchi identity. The most general action invariant under the covariant fracton? transformation consists of two independent terms: one describing Linearized Gravity (LG) and the other referable to fractons, a proof of the always suspected relation between fractons and gravitons. I will also discuss that, as claimed in the Literature, the fracton part can be reconduced to a generalized Maxwell theory. In particular, in the covariant generalization of the fracton theory, the equations describing the fracton limited mobility, i.e. the charge and dipole conservation, are not external constraints, but rather consequences of the field equations of motion, hence of the invariant action and, ultimately, of the fracton covariant symmetry. I will also discuss boundary effects related to this fracton model.$

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