Quantum Optics in Information and Control
Teo Zhi, Colin Wei · 2013
The field of Quantum Optics has transitioned from the original study of the coherences of light, to its present day focus on the treatment of the interactions of matter with various quantum states of lights. This transition was spurred, in part, by the predicted potential of Quantum Information Processing protocols. These protocols take advantage of the coherent nature of quantum states and have been shown to be useful in numerous settings. However, the delicate nature of these coherences make scalability a real concern in realistic systems. Quantum Control is one particular tool to address this facet of Quantum Information Processing and has been used in experiments to great effect. In this thesis, we present our study of the use of Quantum Optics in Quantum Information and Quantum Control. We first introduce some results of InputOutput Theory, which is an elegant formalism to treat open quantum systems. Following which, we expound on work done in collaboration with colleagues from Brazil on a proposal for a loophole-free Bell test. This builds on the results derived using Input-Output theory and includes a semi-analytical formalism to perform the optimization of the Bell inequality. The treatment of this problem is then used to show that with existing optical cavity setups, one is able to produce the required states with a fidelity sufficient to violate a Bell inequality. Next, we present a description of an experiment to produce entangled photon pairs using four-wave mixing, done in collaboration with the experimental group in CQT. Finally, we present a study of quantum optimal control which highlights non-intuitive concepts of Optimal Control Theory.