# Seminar: Quantum Information Theory for Quantum Technologies: Fundamentals with Practical Guidance

**Sumeet Khatri**

*Postdoctoral Researcher, Jens Eisert Group
Freie Universitat Berlin*

Monday, February 13, 2023

11:00 AM - 12:00 PM

via Zoom

### Abstract

The prospect of realizing quantum technologies such as quantum computing, quantum communication, and quantum sensing, has arisen from research on harnessing the quantum-mechanical phenomena of superposition and entanglement for practical purposes. The hope is that by using quantum systems--in the form of qubits--as carriers of information, we might achieve an advantage over classical bits. In this area of research, known as "quantum information theory", we examine information-processing tasks with qubits, and these studies form the foundations of quantum technologies. However, the analysis of quantum information-processing tasks is typically idealized, not always taking realistic physical assumptions into account, and often telling us only what performance benchmarks can in principle be achieved and not necessarily how to achieve them in practice. While such an analysis is an important first step, realizing quantum technologies requires theoretical research at the intersection of theory and practice, using tools from quantum information theory, mathematics, and computer science in order to conduct a performance analysis that models real-world physical constraints, which can then help guide actual implementations. In this talk, I present the ways in which I have undertaken this challenge. I place particular emphasis on prior and ongoing work on the development of tools at the intersection of quantum information theory, performance modeling, and queuing theory to determine optimal policies for long-distance quantum communication under practical physical constraints. I also present some results at the intersection of quantum information theory and variational quantum computing algorithms arising from this practically-oriented mindset, as well as recent work on quantum error mitigation. Looking forward, I outline my plans for future work on quantum information theory for practical purposes in the areas of quantum communication, quantum metrology/sensing, and quantum learning theory, all with the ultimate goal of guiding the burgeoning efforts on bringing quantum technologies outside the lab and into widespread use.

### Biography

Sumeet Khatri is a postdoctoral researcher in the group of Jens Eisert at the Freie Universitat Berlin. He works on topics in quantum information theory, including quantum communication, computing, metrology/sensing, and learning theory, with the goal of providing fundamental, theorectical guidance in order to help bring quantum technologies into real-world, widespread use. He complete his PhD in Physics in May 2021 at Lousiana State University. Prior to that, he earned his Bachelor's degree in Mathematical Physics and Master's degree in Physics at the University of Waterloo. He is co-author of the textbook "Principles of Quantum Communication Theory: A Modern Approach", about the fundamentals of quantum information theory, with an emphasis on quantum communication.