Self-Consistent Determination of Single-Impurity Anderson Model Using Hybrid Quantum-Classical Approach on a Spin Quantum Simulator

TL;DR

This paper demonstrates a hybrid quantum-classical method to accurately determine the electronic structure of strongly correlated materials, using a spin quantum processor to compute the Green's function and achieve self-consistency in the Anderson model.

Contribution

It introduces an experimental hybrid quantum-classical approach that integrates quantum computation into classical frameworks for solving strongly correlated electronic structures.

Findings

Observation of a quantum phase transition in the Hubbard model.

Successful self-consistent determination of the single impurity Anderson model.

Validation of the approach's potential for complex correlated materials.

Abstract

The accurate determination of the electronic structure of strongly correlated materials using first principle methods is of paramount importance in condensed matter physics, computational chemistry, and material science. However, due to the exponential scaling of computational resources, incorporating such materials into classical computation frameworks becomes prohibitively expensive. In 2016, Bauer et al. proposed a hybrid quantum-classical approach to correlated materials Phys. Rev. X 6, 031045 (2016)}] that can efficiently tackle the electronic structure of complex correlated materials. Here, we experimentally demonstrate that approach to tackle the computational challenges associated with strongly correlated materials. By seamlessly integrating quantum computation into classical computers, we address the most computationally demanding aspect of the calculation, namely the computation of the Green's function, using a spin quantum processor. Furthermore, we realize a self-consistent determination of the single impurity Anderson model through a feedback loop between quantum and classical computations. A quantum phase transition in the Hubbard model from the metallic phase to the Mott insulator is observed as the strength of electron correlation increases. As the number of qubits with high control fidelity continues to grow, our experimental findings pave the way for solving even more complex models, such as strongly correlated crystalline materials or intricate molecules.