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Title: Non-Markovian quantum Brownian motion
Author: Werren, Nicholas
ISNI:       0000 0004 9350 3300
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 2020
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We develop a non-Markovian extension to the caldeira-leggett master equation for quantum Brownian motion by using the timescale of the bath as a small parameter around which to perform a perturbative expansion. This framework allows us to deal directly with the time non-locality of the non-Markovian regime. We derive an exact description of the evolution of the reduced density matrix and obtain a new quantum master equa- tion with non-Markovian corrections added perturbatively to the standard Lindblad form. The resulting simulations show new dynamics and a strong deviation from Markovian behaviour. We observe that quantum coherences survive far longer than in the Marko- vian limit. In particular, when the system is fully non-Markovian, quantum phenomena experience a form of decoherence that behaves functionally like an inverse-power law. These results may have important implications in quantum technologies and biology as they suggest environments can be engineered to support long-lived quantum coherence.
Supervisor: Rocco, Andrea ; Al-Khalili, Jim Sponsor: STFC ; University of Surrey
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral