Thermodynamic control and characterisation of levitated quantum systems

Abstract

This thesis explores non-equilibrium phenomena in mesoscopic open quantum system dynamics; which is experimentally relevant for the progress in the control of quantum systems and dynamics in levitodynamics. In particular, the thesis analyses the following three topics: 1) spin systems under the transformation of field or interaction - where we explore the effects of quantum coherence in processes assisted by counterdiabatic driving. We analyse the fundamental relations between the thermodynamic quantities such as quantum coherence, work and irreversible entropy production. 2) a levitated nanoparticle in a double-well potential - where we develop a general framework to compute the Wehrl entropy of the levitated quantum system that is subjected to thermalisation and localisation and undergoes the transition from a harmonic potential to a double-well potential. We explore the real experimental settings in which the quantum and thermal effects have comparable impacts over the system dynamics, quantify requirements that relate our results to a bona fide experiment with the presence of the environment, and provide the experimental interpretations of our results. 3) the squeezing of a levitated system under continuous measurement - where we study the effects of a squeezing protocol on a quantum system with a stochastic dynamics due to the measurement. We consider the levitated system in a quadratic potential such that its dynamics is described by a quantum Gaussian stochastic model, and analyse the amount of squeezing that can be achieved with the levitated system using a dynamical squeezing protocol.

Date of Award	Dec 2023
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	The Leverhulme Trust
Supervisor	Mauro Paternostro (Supervisor) & Gabriele De Chiara (Supervisor)