Department of Physics & Astronomy
University of New Mexico

CQuIC Seminars

Quantum Limits of Reliable and Secure Optical Communications

Presented by Saikat Guha, University of Arizona

The fundamental limits to optical information processing — be it the maximum rate of reliable communication, imaging resolution of an optical sensor or the computational power of an optical computer — are all governed by the laws of quantum mechanics. Most current-day systems, which do not exploit the manifestly quantum effects of light, are limited to performance inferior to these limits. Exploiting the quantum effects of light would not only facilitate more powerful information processing, it would enable the most powerful form of security in various information processing applications — physics-based security — which, instead of relying upon the hardness of computational problems, would be secure to the most powerful adversaries allowed by physics.

In this lecture, I will first briefly talk about the quantum limits of optical communication, and how one might try designing hardware that bridges the gap between the conventional (Shannon-theoretic) limits to communication capacity associated with standard optical receivers, and the ultimate quantum limit, usually known as the Holevo capacity. Then I will delve in more details into the security aspects: the quantum limits associated with secure and covert communication — i.e., reliable communication over a noisy optical channel, while being secure against interception (i.e., the data being decoded) and/or against detection (i.e., the communication attempt being discovered) — against the all-powerful adversary allowed by physics. I will end the lecture with pointers to some recent experimental progress in the field and on the recent results on addressing design challenges of a future quantum communication network.

3:30 pm, Thursday, September 14, 2017
Room 190, Physics & Astronomy
Northeast corner of Lomas and Yale, Albuquerque, New Mexico

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