Colloquium: Saikat Guha

    Thursday, February 19, 2015 - 3:30pm - 5:00pm
    Meinel 307

    "Quantum Limits to Reliable, Secure and Covert Optical Communication"


    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, Guha will first 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. In the second half, Guha will delve 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. He will end the lecture with pointers to some recent experimental progress in the field and a few high-level thoughts on the prospects and design challenges of a future quantum communication network.

    Speaker Bio(s): 

    Saikat Guha is a senior scientist in the Quantum Information Processing group at Raytheon BBN Technologies. He earned his B.Tech. degree in electrical engineering in 2002 from the Indian Institute of Technology Kanpur (India), followed by S.M. and Ph.D. degrees in 2004 and 2008 respectively, from the department of electrical engineering and computer science at the Massachusetts Institute of Technology. His research interests span quantum limits to optical communication and sensing, optical quantum computing, and network information theory. Guha represented India at the International Physics Olympiad in 1998, where he was awarded the European Physical Society award for the experimental component. He was a co-recipient of a NASA Tech Brief award in 2010 in recognition of his work on novel receivers for quantum imaging. His Defense Advanced Research Projects Agency Information in a Photon team won the Raytheon 2011 Excellence in Engineering and Technology Award, Raytheon's highest technical honor, for outstanding research on fundamental limits of optical communication. Goha currently leads several research projects funded by DARPA, Office of Naval Research, National Science Foundation and the U.S. Department of Energy, on various topics spanning quantum-limited optical information processing.