Abstracts:

Why the buzz around quantum LDPC codes?

Ani Krishna: Quantum LDPC codes have attracted a lot of attention recently. In this talk, I will discuss why these codes are being studied from the perspective of fault-tolerant quantum computation. I will first discuss asymptotic guarantees—we expect that these codes will offer an efficient way to construct scalable quantum computers. This efficiency might not be available to all architectures—I shall discuss what your architecture needs to be able to do for you to be able to build these codes. I will then discuss some desiderata to translate asymptotic results to real-world applications

Research interests: quantum error correction and fault-tolerant quantum computation.

Gauge dualities for (good) LDPC codes

Tibor Rakovszky: This talk will discuss various recent ideas and constructions in (quantum) computer science from a physics perspective. I will introduce quantum LDPC codes, examples of which include the familiar toric code, fracton models, and more exotic systems that live on so-called expander graphs, and explain how all of these can be understood as generalized versions of Z2 gauge theories, familiar from high energy and condensed matter physics. I will use this perspective to relate properties of quantum and classical codes, using a form of generalized gauge duality; in particular to explore the relationship between the code distance of the quantum code and a property of classical codes called "local testability", which can be understood in terms of the scaling of energy barriers. Along the way, I will introduce various product constructions that can be used to systematically generate new models with interesting properties out of simpler ones. 

Research interests: condensed matter theory, quantum many-body dynamics and (more recently) quantum error correction.