Princeton University

School of Engineering & Applied Science

Efficient Fault-Tolerant Quantum Computing

Dr. Martin Suchara, AT&T Labs Research
Bowen Auditorium
Monday, November 14, 2016 - 12:00pm

Quantum error correction presents some of the most significant and interesting challenges that must be resolved before building an efficient quantum computer. Quantum error correcting codes allow to successfully run quantum algorithms on unreliable quantum hardware. Because quantum hardware suffers from errors such as decoherence, leakage or qubit loss, and these errors corrupt delicate quantum states rather than binary information, the known error correction techniques are complex and have a high overhead.
In my talk I first introduce the two main families of quantum error correcting codes and quantify their overhead using specific examples of algorithms and hardware technologies. Then I describe several new techniques that I developed to reduce this overhead. For example, the maximum likelihood decoder (MLD) is an efficient algorithm that finds the recovery operation that maximizes the probability of a successful error correction given the observed error syndrome. Numerical simulations of the MLD algorithm for physical error rates around 10% showed a 100 fold reduction of the logical error probability compared to earlier techniques. I also show new designs of error correcting codes that are tailored to work more efficiently with the constraints of specific physical technologies.

Bio: Martin Suchara is a Principal Inventive Scientist at AT&T Labs Research since 2015. Prior to joining AT&T he was a Postdoctoral Scholar in the quantum computing group at IBM T. J. Watson Research Center. His work focuses on making computation with quantum computers more efficient and reliable. He developed new quantum error correcting codes that improve error decoding efficiency. Martin received his PhD from the Computer Science department at Princeton University and postdoctoral training from UC Berkeley. Between 2011 and 2013 he coordinated the work of a small group of postdocs and students on the IARPA Quantum Computer Science Program and delivered the results to the Program Manager. Martin is the recipient of the Best Student Paper Award at ACM Sigmetrics 2011.