In the 13th session, Dr. Satvik Singh gave a talk on "Gaussian mean width strong converse bound on identification via quantum channels".
Dr. Satvik Singh is a postdoctoral researcher in the Quantum Information Theory group at the Technical University of Munich. He received his PhD in Theoretical and Mathematical Physics from the University of Cambridge, where he worked on quantum channel capacities under the supervision of Prof. Nilanjana Datta, and previously completed his BS-MS studies at IISER Mohali. His research lies at the intersection of quantum information theory, entanglement theory, mathematical physics, and quantum channel theory, with a particular focus on communication capacities, noise, and structural properties of quantum channels.
Abstract
Identification via a noisy channel is a communication task where, instead of requiring the receiver to recover the full transmitted message, we only ask him to decide/identify whether a particular message was sent or not. This small change leads to a striking difference: identification codes can grow doubly exponentially in the block-length as opposed to the single exponential growth of ordinary transmission codes. In this talk, I will discuss the task of classical message identification via quantum channels. I will present a new strong converse bound on the (doubly exponential) identification capacity of quantum channels based on the geometric notion of Gaussian mean width. The resulting bound is single-letter, efficiently computable, and improves known converse bounds for several important channels, including depolarizing, erasure, Pauli, and amplitude damping channels.
This talk is based on arXiv:2606.05032.