Previous APMS Colloquia

Spring 2026

Thursday, January 22, 9:45-10:45 am

Dr. Diego Dalvit
Los Alamos National Laboratory

Quantum Radar with Undetected Photons

Abstract: Quantum sensing promises to revolutionize sensing applications by employing quantum states of light or matter as sensing probes. Photons are the clear choice as quantum probes for remote sensing because they can travel to and interact with a distant target. Existing schemes are mainly based on the quantum illumination framework, which requires a quantum memory to store a single photon of an initially entangled pair until its twin reflects off a target and returns for final correlation measurements. Existing demonstrations are limited to tabletop experiments, and expanding the sensing range faces various roadblocks, including long-time quantum storage and photon loss and noise when transmitting quantum signals over long distances. We propose a novel quantum sensing framework that addresses these challenges using quantum frequency combs with path identity for remote sensing of signatures (“qCOMBPASS”). The combination of one key quantum phenomenon and two quantum resources, namely quantum induced coherence by path identity, quantum frequency combs, and two-mode squeezed light, allows for quantum remote sensing without requiring a quantum memory. The proposed scheme is akin to a quantum radar based on entangled frequency comb pairs that uses path identity to detect/range/sense a remote target of interest by measuring pulses of one comb in the pair that never flew to target, but that contains target information “teleported” by quantum-induced coherence from the other comb in the pair that did fly to target but is not detected. This work was recently published in D.A.R. Dalvit et.al., Quantum Frequency Combs with Path Identity for Quantum Remote Sensing, PRX 14, 041058 (2024).

Bio: Diego Dalvit is a Senior Staff Member at the Theoretical Division of Los Alamos National Laboratory. He is a quantum optics theorist with expertise in quantum sensing and metrology, Casimir physics, and metamaterials. He received his Ph.D. in Physics from Universidad de Buenos Aires (Argentina) in 1998, came to LANL in 1999 as a Director Funded Postdoctoral Fellow, and was converted to staff in 2002. He is a Fellow of the American Physical Society (APS) and Optica (former Optical Society of America), and APS Outstanding Referee. He has authored more than 100 peer-reviewed papers, with more than 9,600 citations. He has also co-authored two physics textbooks, one a guide to the essence of Casimir physics, and one a volume on statistical mechanics. He is the holder of two patents, including one submitted in 2024 in connection to his development of the groundbreaking qCOMBPASS quantum
remote sensing technology. His hobbies are bodybuilding and aircraft spotting.