Date of Award

2022

Document Type

Thesis (Ph.D.)

Department or Program

Physics and Astronomy

First Advisor

Miles Blencowe

Second Advisor

Robert Caldwell

Third Advisor

Marcelo Gleiser

Abstract

In this work we study various aspects of the quantum dynamics for a system coupled to a Bosonic environment, which is described by a collection of quantum harmonic oscillators or a quantum field. We first consider two quantum mechanical oscillator system-bath models obtained by dimensionally truncating linearized gravity coupled to a massive scalar field and scalar QED, and we show that they separately map onto the phase damped oscillator model and the oscillator system subject to two-photon damping. The phase damped oscillator model also corresponds to the optomechanical system with an acoustic field environment, and we study the acoustic environment induced cavity modes dephasing dynamics as well as the possible infrared and ultraviolet divergence dependence on the spatial dimension of the environment with potential experimental realizations. Next, we show that the acoustic phonon field can not only induce the depahsing effects for the system, but also serves as an entanglement channel for two initially separable systems, which bears similarities with the weak, quantum gravitational fields as mediators of quantum entanglement. We then shift our focus to another system-bath model: Unruh-Dewitt (UDW) detectors coupled to a scalar field. We consider two scenarios here; one includes two UWD detectors coupled to a massless scalar field in a gravitational wave spacetime and we show that the entanglement harvested by two detectors depends sensitively on the frequency of the gravitational wave. The resonance effects can be observed when the energy gap of the detectors matches the frequency of the gravitational wave. The other one consists of a UWD detector initially in the ground state coupled to a nonrelativistic particle state of a massive scalar field, and it is found that the transition probability of the detector (which can be interpreted as the probability of detecting the particle at the location of the UWD detector) is qualitatively similar to the non-relativistic probability density of the particle.

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