Quantum simulation of two-dimensional quantum chemistry in optical lattices

Javier Argüello-Luengo,Peter Zoller,Alejandro González-Tudela,J Ignacio Cirac,Tao Shi

doi:10.1103/physrevresearch.2.042013

Abstract

Benchmarking numerical methods in quantum chemistry is one of the key opportunities that quantum simulators can offer. Here, we propose an analog simulator for discrete 2D quantum chemistry models based on cold atoms in optical lattices. We first analyze how to simulate simple models, like the discrete versions of H and H$_2^+$, using a single fermionic atom. We then show that a single bosonic atom can mediate an effective Coulomb repulsion between two fermions, leading to the analog of molecular Hydrogen in two dimensions. We extend this approach to larger systems by introducing as many mediating atoms as fermions, and derive the effective repulsion law. In all cases, we analyze how the continuous limit is approached for increasing optical lattice sizes.

Highlights

Benchmarking numerical methods in quantum chemistry is one of the key opportunities that quantum simulators can offer
We have shown how ultracold atoms moving in 2D optical lattices can be used to simulate simplified models for quantum chemistry in today’s experimental setups
We have observed that early experiments with a single simulating atom can pursue the timely goal of simulating the simplest discretized atom and molecule in this platform

Summary

Rapid Communications

Javier Argüello-Luengo ,1,* Alejandro González-Tudela ,2,† Tao Shi,3,‡ Peter Zoller, and J. We propose an analog simulator for discrete two-dimensional quantum chemistry models based on cold atoms in optical lattices. Density functional theory (DFT) [2,3] has enabled a better description and understanding of both static [4,5,6,7] and dynamic [8] properties of a large variety of molecules The capability of such computational methods, whose main challenge is to address electronic correlations, is sometimes hard to assess experimentally. While quantum computers and analog simulators would certainly help to push quantum chemistry, the exploration of their full potentiality requires the development of techniques that go beyond the state of the art.

Scheme II ta tb

Conclusions and outlook

We acknowledge support from the ERC