999 research outputs found
The physics of optical computing
There has been a resurgence of interest in optical computing over the past
decade, both in academia and in industry, with much of the excitement centered
around special-purpose optical computers for neural-network processing. Optical
computing has been a topic of periodic study for over 50 years, including for
neural networks three decades ago, and a wide variety of optical-computing
schemes and architectures have been proposed. In this paper we provide a
systematic explanation of why and how optics might be able to give speed or
energy-efficiency benefits over electronics for computing, enumerating 11
features of optics that can be harnessed when designing an optical computer.
One often-mentioned motivation for optical computing -- that the speed of light
is fast -- is not a key differentiating physical property of optics for
computing; understanding where an advantage could come from is more subtle. We
discuss how gaining an advantage over state-of-the-art electronic processors
will likely only be achievable by careful design that harnesses more than one
of the 11 features, while avoiding a number of pitfalls that we describe.Comment: 31 pages; 11 figure
Synchronously-pumped OPO coherent Ising machine: benchmarking and prospects
The coherent Ising machine (CIM) is a network of optical parametric oscillators (OPOs) that solves for the ground state of Ising problems through OPO bifurcation dynamics. Here, we present experimental results comparing the performance of the CIM to quantum annealers (QAs) on two classes of NP-hard optimization problems: ground state calculation of the Sherrington-Kirkpatrick (SK) model and MAX-CUT. While the two machines perform comparably on sparsely-connected problems such as cubic MAX-CUT, on problems with dense connectivity, the QA shows an exponential performance penalty relative to CIMs. We attribute this to the embedding overhead required to map dense problems onto the sparse hardware architecture of the QA, a problem that can be overcome in photonic architectures such as the CIM
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