IQIM Postdoctoral and Graduate Student Seminar

Abstract: Performing large-scale, accurate quantum simulations of many-fermion systems is a central challenge in quantum science, with applications in chemistry, materials, and high-energy physics. In this talk, we will discuss recent results on (1) efficiently encoding fermionic algorithms into qubit based quantum devices and (2) implementing fault-tolerant quantum simulation algorithms with high-rate logical operations. In the first part of the talk, we present a method for faster fermionic simulation with asymptotic space-time overhead of O(log(N)) in the worst case, and O(1) for circuits with additional structure, representing an N/\log(N) improvement over the prior state-of-the-art. This exponential reduction is achieved by using reconfigurable quantum systems with non-local connectivity, mid-circuit measurement, and classical feedforward, to generate dynamical fermion-to-qubit mappings. In the second part of the talk, we outline an approach for high-rate computation with qLDPC codes, by constructing batched fault-tolerant operations that apply the same logical gate across many code blocks in parallel. By leveraging shared physical resources to execute many logical operations in parallel, these operations realize high rates in space-time and significantly reduce computational costs. Finally, we show how these techniques can be combined, to generate high-rate fermionic quantum simulation algorithms with low encoding overhead into a fault-tolerant qubit-based device.

Following the talk, lunch will be provided on the lawn outside East Bridge.