Physics colloquium-“Spectrally-Multiplexed Entanglement Swapping of Time-Frequency Entangled Photons”

Brian Smith

University of Oregon

Abstract: Entanglement, the correlations displayed between sub- systems of a multipartite quantum system, is one of the most distinguishing properties of quantum physics and a significant resource for quantum information science and technology. Entanglement swapping is a protocol that enables entanglement of quantum systems that have never interacted. This protocol underpins efforts to realize large-scale quantum networks as the core element of quantum repeaters. Entanglement swapping between entangled photons has been experimentally demonstrated using photons entangled in their polarization, spatial, and temporal degrees of freedom. Here we focus on encoding information in the spectral-temporal mode of single photons. This allows for a multiplexed approach to entanglement swapping that can generate many different entangled two-photon states. The entanglement swapping protocol relies on multimode entangled photon-pair sources and the ability to perform spectrally-resolved single-photon detection. Experimental results demonstrating the generation of 5 nearly-orthogonal two-photon states is presented.

Biography: Brian J. Smith is Professor of Physics at the University of Oregon, where he leads the Optical Quantum Technologies (OQT) research group. Prior to this Dr Smith was Associate Professor of Experimental Quantum Physics in the Department of Physics at the University of Oxford from 2010 to 2016. He was a Senior Research Scientist at the National University of Singapore 2009-2010, where he worked on integrated quantum photonics, and quantum-enhanced sensing. He was a Royal Society Postdoctoral Fellow 2007-2009 at the University of Oxford where he worked on controlled photonic quantum state preparation and manipulation, quantum measurement characterization, and quantum-enhanced sensing. He obtained a PhD in Experimental Quantum Optics from the University of Oregon in 2007 and BA degrees in Physics and Mathematics from Gustavus Adolphus College in 2000. Smith’s current research interests lie in the general areas of quantum optics and quantum technologies and their use in probing fundamental quantum physics and realizing quantum-enhanced applications with performance beyond that possible with classical resources. In these fields he has developed approaches for producing non-classical states of light with well-defined mode structure based upon engineered nonlinear optics, methods to coherently manipulate such quantum states, and efficient means to measure the resultant states. Recently his efforts have focused on harnessing the temporal-spectral mode structure of light to enable realization of larger quantum systems. These quantum-optical tools have enabled him to examine fundamental questions in quantum physics, such as the commutation relations for creation and annihilation operations, and experimentally address various quantum-enhanced technologies, for example quantum-enhanced sensing and quantum communications.

Lecture via Zoom