Applications of Single-Photon Two-Qubit Quantum Logic to the Quantum Information Science

Abstract

In this thesis, I describe demonstration of various quantum information processing tasks using single-photon two-qubit (SPTQ) quantum logic. As an initial state of those tasks, I used various entangled photon pairs, and I describe development of a polarization entangled photon pair source based on a collinear spontaneous parametric down conversion (SPDC) process within a bidirectionally pumped periodically-poled potassium titanyl phosphate (PPKTP) crystal embedded in a polarization Sagnac in- terferometer and generation of hyper-entangled photon pairs that are simultaneously entangled in the polarization and momentum degrees of freedom. I also introduce deterministic quantum gates based on SPTQ quantum logic where the polarization and momentum degrees of freedom in a single photon are used as two qubits. By applying SPTQ quantum logic to di®erent entangled states, I demonstrate several quantum information tasks such as transferring entanglement from the momentum qubits to the polarization qubits, SPTQ-based complete polarization Bell state mea- surements, entanglement distillation (Schmidt projection), and a physical simulation of the entangling-probe attack on the Bennett-Brassard 1984 (BB84) quantum key distribution (QKD).