Quantum Computing and Designer Photon-Photon Interactions

Speaker: Josh Combes, Ph.D.
Affiliation: Rigetti Computing

Abstract: Optical quantum computers are one of the many ways humankind is trying to build a quantum computer. Surprisingly, they are also one of the oldest ways. The key component of current optical quantum computers, a two-qubit gate, only works 7% of the time. This means the computation is inefficient in some sense. There is much debate over whether it is possible to build a deterministic two-qubit gate. The main contention is that the multi-frequency nature of travelling photons precludes a high-quality gate. This was pointed out in two famous ‘no-go’ results. However, recent advances in experimental nonlinear quantum optics, at the single photon and single atom level, motivate reexamining these no-go results. In this talk I will show that it is possible to engineer interactions between photons so that one can build a deterministic optical quantum computer, solving a ten-year-old problem in quantum computing and quantum optics. Finally, I will discuss implications of these results for the use of effective field theory in the description of nonlinear dielectric and the cluster decomposition theorem.

Biography: Josh Combes obtained his B.S and B.Eng. in 2003 and Ph.D. in 2010 from Griffith University. Previously, he has worked at the Australian National University, University of New Mexico, the Institute for Quantum Computing, Perimeter Institute for Theoretical physics, and the University of Queensland. He has taken a leave of absence from his Australian Research Council fellowship to join the device physics and applications research team at Rigetti quantum computing as a senior theorist. Josh works on quantum measurement theory and aspects of quantum information and computation.

For more information, contact Prof. Chee Wei Wong ()

Date(s) - Feb 27, 2019
11:00 am - 12:15 pm

EE-IV Shannon Room #54-134
420 Westwood Plaza - 5th Flr., Los Angeles CA 90095