Dissipative variational quantum algorithms for Gibbs state preparation

TL;DR

This paper introduces dissipative variational quantum algorithms that incorporate dissipative operations to improve the robustness and accuracy of Gibbs state preparation on noisy intermediate-scale quantum devices.

Contribution

The paper presents a novel dissipative variational quantum algorithm framework that enhances noise resilience and does not require ancilla qubits for Gibbs state preparation.

Findings

D-VQAs can prepare Gibbs states across various Hamiltonians and temperatures.

The approach significantly reduces errors from both coherent and non-coherent noise.

No ancilla qubits are needed in the proposed algorithms.

Abstract

In recent years, variational quantum algorithms (VQAs) have gained significant attention due to their adaptability and efficiency on near-term quantum hardware. They have shown potential in a variety of tasks, including linear algebra, search problems, Gibbs and ground state preparation. Nevertheless, the presence of noise in current day quantum hardware, severely limits their performance. In this work, we introduce dissipative variational quantum algorithms (D-VQAs) by incorporating dissipative operations, such as qubit RESET and stochastic gates, as an intrinsic part of a variational quantum circuit. We argue that such dissipative variational algorithms posses some natural resilience to dissipative noise. We demonstrate how such algorithms can prepare Gibbs states over a wide range of quantum many-body Hamiltonians and temperatures, while significantly reducing errors due to both coherent and non-coherent noise. An additional advantage of our approach is that no ancilla qubits are need. Our results highlight the potential of D-VQAs to enhance the robustness and accuracy of variational quantum computations on NISQ devices.