Welcome!

I’m currently a graduate student in the Quantum Science and Technologies Group in the Hearne Institute for Theoretical Physics at Louisiana State University under the supervision of Mark Wilde.  Previously, I was a Master’s student at the Institute for Quantum Computing at the University of Waterloo under the supervision of Norbert Lütkenhaus.

My research is in the general area of quantum information theory. For the past couple of years my focus has been on quantum cryptography, specifically quantum key distribution. I am also interested in quantum networks as well as quantum computing, specifically applying machine learning methods to quantum algorithms for near-term applications. Check out my research for details on what I’ve been working on, as well as my Google Scholar page and my papers on arXiv. I’ve also compiled a list of introductory resources on the topics pertaining to my research and to physics in general.

You can contact me at skhatr5 [at] lsu [dot] edu.

Latest Papers

Information-theoretic aspects of the generalized amplitude damping channel

Abstract:

The generalized amplitude damping channel (GADC) is one of the sources of noise in superconducting-circuit-based quantum computing. It can be viewed as the qubit analogue of the bosonic thermal channel, and it thus can be used to model lossy processes in the presence of background noise for low-temperature systems. In this work, we provide an information-theoretic study of the GADC. We first determine the parameter range for which the GADC is entanglement breaking and the range for which it is anti-degradable. We then establish several upper bounds on its classical, quantum, and private capacities. These bounds are based on data-processing inequalities and the uniform continuity of information-theoretic quantities, as well as other techniques. Our upper bounds on the quantum capacity of the GADC are tighter than the known upper bound reported recently in [Rosati et al., Nat. Commun. 9, 4339 (2018)] for the entire parameter range of the GADC, thus reducing the gap between the lower and upper bounds. We also establish upper bounds on the two-way assisted quantum and private capacities of the GADC. These bounds are based on the squashed entanglement, and they are established by constructing particular squashing channels. We compare these bounds with the max-Rains information bound, the mutual information bound, and another bound based on approximate covariance. For all capacities considered, we find that a large variety of techniques are useful in establishing bounds.