Stanford University

Information technologies at the fundamental physical limits

Special seminar, hosted by Prof. Subhasish Mitra.

Fundamental physical laws dictate the performance bounds of all technologies. Over the last century, nanotechnology and integrated circuits have driven computing, communications, and sensing toward these bounds. As scaling continues, classical limits increasingly constrain further improvements. The advent of quantum technologies opens paths to overcoming some of them by leveraging non-classical resources. In this pursuit, it is prudent to unite the development of quantum and conventional technologies under the bounds arising from fundamental physical laws. In this talk, I give an overview of the fundamental physical limits in computing, communications, and sensing. Across these three domains, I present large-scale integrated systems we realized in silicon photonics and electronics that serve as a proof of concept for deployable technologies operating at these limits. The demonstrations and proposals include (i) quantum computers on CMOS, together with hybrid classical–quantum computing architectures, (ii) quantum coherent transceivers that encode information in non-classical light and surpass the Shannon limit toward the Holevo limit, and (iii) quantum phased arrays and squeezed-light sensors that surpass the standard quantum limit toward the Heisenberg limit. For each system, I address the theory, design, experiment, and application, and outline a vision for how these technologies can be practically deployed in the future, with an economically scalable path within today’s CMOS infrastructure.