Mutual information-assisted adaptive variational quantum eigensolver. (2nd August 2021)

• Record Type: Journal Article
• Authors: Zhang, Zi-Jian; Kyaw, Thi Ha; Kottmann, Jakob S; Degroote, Matthias; Aspuru-Guzik, Alán
• Is Part Of: Quantum science and technology. Volume 6:Number 3(2021)
• Publication Date: 2021-08-02
• Subjects: quantum computing -- variational quantum eigensolver -- quantum computational chemistry; Quantum theory -- Periodicals; Quantum theory; Periodicals; 530
• DOI: 10.1088/2058-9565/abdca4
• Languages: English
• ISSNs: 2058-9565

Abstract

Abstract: Adaptive construction of ansatz circuits offers a promising route towards applicable variational quantum eigensolvers on near-term quantum hardware. Those algorithms aim to build up optimal circuits for a certain problem and ansatz circuits are adaptively constructed by selecting and adding entanglers from a predefined pool. In this work, we propose a way to construct entangler pools with reduced size by leveraging classical algorithms. Our method uses mutual information between the qubits in classically approximated ground state to rank and screen the entanglers. The density matrix renormalization group method is employed for classical precomputation in this work. We corroborate our method numerically on small molecules. Our numerical experiments show that a reduced entangler pool with a small portion of the original entangler pool can achieve same numerical accuracy. We believe that our method paves a new way for adaptive construction of ansatz circuits for variational quantum algorithms.