QSimFP QBH Seminar: Ambient temperature in the circular motion Unruh effect

Abstract: The Unruh effect lies at the interface of quantum field theory and general relativity, predicting that detectors in accelerated and inertial motion experience the quantum vacuum differently - the former measures a response when the latter does not. The excitation and de-excitation rates of this response have the characteristics of a thermal spectrum at a temperature directly proportional to the proper acceleration of the accelerated detector. Measuring this effect, however, has proven remarkably difficult: a 1K increase in temperature would require an acceleration of the order 10^20m/s^2.
Since the discovery by Unruh in 1981 of the analogy between linearised surface perturbations in an inviscid fluid and a massless scalar field on a curved background, analogue gravity as a field has opened up previously inaccessible regimes to experimental probing in hydrodynamical, condensed matter, and optical systems. These systems offer analogue spacetimes as playgrounds for testing theoretical phenomena. However, the experiment must be contained within a finite size and such systems exhibit non-zero temperatures. As such, by expanding the theoretical framework to include a finite temperature with a detector in circular motion (constant acceleration), this work aims to bring experiment and theory closer together.

In this talk, I will review the Unruh-DeWitt detector model applied to a field at a nonzero ambient, explore the detector's response function, and apply this formalism to a superfluid helium setup. Rather than being a hinderance, the ambient temperature can be found to enhance acceleration-dependent response.

This talk is based on the works 2303.12690 and 2302.12023

Biosketch: Cameron Bunney is a final-year PhD student at University of Nottingham under Prof. Jorma Louko and Prof. Silke Weinfurtner. Before starting his PhD in 2020, he completed an MMath at University of Nottingham. His work has focused on experimental modelling for the circular motion Unruh effect.