Quantum resources in superposition of casual orders enhancing channel capacity

• Main Author: Singh, Isha Le Xue
• Other Authors: Gu Mile
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Science::Physics
• Online Access: https://hdl.handle.net/10356/148398
• Institution: Nanyang Technological University

The ability to enhance quantum channels is an important aspect of quantum information and the enhancing of two completely depolarising channel by putting them through indefinite causal order is a fascinating result. In this report, this idea will be studied through two models, one using completely depolarising channels while the other uses complete erasure channels. By analysing the expectation value of measurements, Holevo bound, and coherence measures, it is observed that both models are enhanced, regardless of whether the channels are completely depolarising, and that the improvement in channel capacity increases with increasing coherence. It is also observed that by setting certain constraints on the initial states, the expectation value of measurements can be used as a valid quantifier of coherence.