The following are the videos of the talk which Prof. Yoshihisa Yamamoto gave on January 21, 2014 at Stanford University.
This is the processed (combined to a single file and compressed) video of the entire talk:
The following are the original video files which have originally been recorded with the camera.
Each of the 5 files has a size of around 1 GB and a length of around 15 min.
Stanford University
APPLIED PHYSICS/PHYSICS COLLOQUIUM
Tuesday, January 21, 2014
4:15 p.m. on campus in Hewlett Teaching Center, Rm. 201
Refreshments in the Physics Lobby at 4:00 p.m.
Yoshi Yamamoto
Stanford University
"Coherent Computing by OPO Phase Transition"
Combinatorial optimization problems are ubiquitous in our modern life. Most of those problems belong to NP-hard or NP-complete class, for which no efficient classical or quantum algorithm has been discovered so far. A three-dimensional Ising model, which is a mathematical abstraction of spin glasses, is a classic example of NP-hard problems. In this talk, a degenerate optical parametric oscillator (OPO) network is proposed as a coherent Ising machine. We experimentally demonstrate the machine can find the ground state of the NP-hard Ising problem. The underlying operation mechanism originates from the bistable phase transition of each OPO and the preference of the OPO network in selecting the particular phase configuration with the minimum photon loss. A few quantum optics techniques will be discussed toward scalable computing systems, such as fiber based OPO, quantum feedback control and squeezing vacuum fluctuations. The future prospect of coherent computing is compared to those of quantum computing and quantum annealing.