Search results for "Dissipative quantum systems"

DISSIPATIVE DYNAMICS OF MULTI-STATE QUANTUM SYSTEMS IN THE WEAK TO STRONG COUPLING REGIME

In this thesis the dissipative dynamics of bistable quantum systems is studied within the path integral approach. The path integral representation of the propagator for quantum states and density matrices of discrete variable systems is described along with the Feynman-Vernon influence functional. The main approximations to the FV influence for the spin-boson model are introduced and applied to a bistable system beyond the two-level system approximation, the so-called double-doublet system. By the combined use of the Bloch-Redfield perturbative approach and of the path integral techniques, a phase diagram showing the various dynamical and dissipative regimes of the double-doublet system is …

Accelerated stabilization of coherent photon states

2018

| openaire: EC/H2020/681311/EU//QUESS Control and utilization of coherent states of microwave photons is a ubiquitous requirement for the present and near-future implementations of solid-state quantum computers. The rate at which the photon state responds to external driving is limited by the relaxation rate of the storage resonator, which poses a trade-off between fast control and long storage time. Here, we present a control scheme that is designed to drive an unknown photon state to a desired coherent state much faster than the resonator decay rate. Our method utilizes a tunable environment which acts on an ancillary qubit coupled to the resonator. By periodically resetting the qubit and…