Application of the Jaynes-Cummings model in quantum information processing

Abstract

The advent of quantum computation and information science has seen the re-emergence of squeezed states of light being of critical importance in the field of quantum metrology. The generation of the squeezed states of light in circuit QED has proven to achieve quantum measurement in a faster way than conventional optical methods. The Jaynes-Cummings physics is used to study the degree of squeezing generated in a dissipative atom-cavity system by computing the master equation of the interacting atom-cavity quantum system. The collapse-revival oscillations of the dynamical process in the Markovian and non-Markovian regime are observed to be dependent on the coupling strength g of the two-level atom-cavity quantum system including those of the Bohr frequency. By transforming the original Rabi Hamiltonian to a dispersive Hamiltonian, significant squeezing can be observed through sudden qubit flips via the squeezing protocol scheme presented. The degree of squeezing is calculated after N cycles of the protocol are carried out at certain frequency jumps. A comparison of the degree of squeezing generated by the dispersive model and the Rabi model carried out by the frequency-shift protocol proves that the degree of squeezing in the Rabi model is higher. We implement the generation of light squeezing in a quantum circuit environment by first developing a hybrid quantum system consisting of superconducting flux qubits and an ensemble of nitrogen-vacancy centers (NVE). Within such an architecture one of the most important thing to measure is the entanglement between the flux qubits and NV ensemble. This we will measure using a metric called concurrence C. An ideal quantum circuit should be able to effectively store quantum memory and have long coherence times through spin ensembles. We measure bipartite, residual and dissipative entanglement dynamics using concurrence. We conclude the thesis by introducing a novel technique to genearate squeezed states of an NVE within a hybrid quantum system by making use of the superconducting qubit which couples the resonator to the NVE so that we can generate single-mode squeezed states of an NVE from the entangled states of the bosonic mode with the NVE