IEM Distinguished Lecturers Seminar: Computing with Physical Systems


Event details

Date 28.05.2024
Hour 13:1514:00
Speaker Prof. Peter McMahon,
Applied and Engineering Physics, Cornell University, USA
Location Online
Category Conferences - Seminars
Event Language English
The seminar will take place in ELA 2 and will be simultaneously broadcasted in Neuchâtel Campus MC B1 273.

Coffee and cookies will be served from 13:00.


Conventional digital computing technology based on complementary metal–oxide–semiconductor (CMOS) devices has accumulated a performance increase in excess of 1,000,000x versus the first CMOS digital processors. However, the demand for more computing power (and simultaneously increased energy efficiency) – especially for neural networks and for processing a deluge of sensor data – has increased far more rapidly than what even the already-brisk pace of advances in modern processors and special-purpose accelerator chips have been able to deliver. How can we meet this demand over the next decade and beyond?

We study how, by relaxing or breaking some of the tenets of modern computing – such as digital signals, deterministic behavior, computational universality, and a hierarchy of abstractions from digital logic through to software – and reimagining how computers are built at the fundamental level of physical dynamics, we may be able to make orders-of-magnitude leaps in speed or efficiency in specialized co-processors.

In this talk I will briefly introduce the general research program of physics-based computing and then focus on a concrete example, physical neural networks [1]. I will describe a method my group has developed to train any complex physical system to perform as a neural network for machine-learning tasks, and then give an application of this method to a new kind of on-chip photonic neural processor we have developed: one whose refractive index as a function of space we can reprogram with light [2]. I will also discuss the potential of physical neural networks for smart sensors that pre-process acoustic, microwave or optical signals in their native domain before digitization [3].

[1] L.G. Wright*, T. Onodera* et al. Nature 601, 549-555 (2022)
[2] T. Onodera*, M. Stein* et al. arXiv:2402.17750 (2024)
[3] T. Wang*, M. Sohoni* et al. Nature Photonics 17, 408 (2023)

Short biography
Peter McMahon is an assistant professor in Applied and Engineering Physics at Cornell University, where he has been since 2019. Prior to joining Cornell he completed his Ph.D. in Electrical Engineering and postdoctoral training in Applied Physics at Stanford University. He is the recipient of Packard and Sloan Fellowships, an Office of Naval Research Young Investigator Program Award and a Google Quantum Research Award, and is a CIFAR Azrieli Global Scholar in Quantum Information Science.