David McGady, "Path integrals, finite temperature, and lattices"

Tuesday 23 Oct 2018, 14:00 → 16:00 Europe/Zurich

4/3-006 - TH Conference Room (CERN)

Surprisingly, partition functions for some model systems in
statistical mechanics are invariant under formally reflecting the sign
of temperature, T: +T -> -T. We call this T-reflection invariance.
Clearly, partition functions for generic statistical systems cannot be
invariant under T-reflection. However, in this talk we focus on
finite-temperature path integrals and give a general picture for why
finite-temperature path integrals in quantum field theory *should*
behave well under T-reflection. We probe this general picture in the
context of the harmonic oscillators (in one-dimension) and in
conformal field theories on the two-torus (in two-dimensions) and in
the mathematics of modular forms. We find that the relevant path
integrals are often invariant only up to overall T-independent phases,
which could be naturally interpreted as new anomalies under large
coordinate transforms.

This talk is based off of work related to the following four recent papers:
https://arxiv.org/abs/1711.07536
https://arxiv.org/abs/1806.09873
https://arxiv.org/abs/1806.09874
https://arxiv.org/abs/1806.09875