Digital quantum simulation of fermionic models with a superconducting circuit

TL;DR

This paper demonstrates the digital quantum simulation of fermionic models, specifically the Hubbard model, using superconducting circuits, showcasing the potential for scalable quantum simulations of complex many-body systems.

Contribution

It introduces a universal digital approach to simulate fermionic interactions in superconducting circuits, overcoming previous control challenges.

Findings

Successfully simulated fermionic interactions with up to four modes

Performed time evolution and dynamic phase transition simulations

Achieved high fidelities limited mainly by gate errors

Abstract

Simulating quantum physics with a device which itself is quantum mechanical, a notion Richard Feynman originated, would be an unparallelled computational resource. However, the universal quantum simulation of fermionic systems is daunting due to their particle statistics, and Feynman left as an open question whether it could be done, because of the need for non-local control. Here, we implement fermionic interactions with digital techniques in a superconducting circuit. Focusing on the Hubbard model, we perform time evolution with constant interactions as well as a dynamic phase transition with up to four fermionic modes encoded in four qubits. The implemented digital approach is universal and allows for the efficient simulation of fermions in arbitrary spatial dimensions. We use in excess of 300 single-qubit and two-qubit gates, and reach global fidelities which are limited by gate errors. This demonstration highlights the feasibility of the digital approach and opens a viable route towards analog-digital quantum simulation of interacting fermions and bosons in large-scale solid state systems.