Real- and Imaginary-Time Evolution with Compressed Quantum Circuits

• Published in: PRX quantum Vol. 2; no. 1; p. 010342
• Main Authors: Lin, Sheng-Hsuan, Dilip, Rohit, Green, Andrew G., Smith, Adam, Pollmann, Frank
• Format: Journal Article
• Language: English
• Published: American Physical Society 01-03-2021
• ISSN: 2691-3399; 2691-3399
• DOI: 10.1103/PRXQuantum.2.010342

The current generation of noisy intermediate-scale quantum computers introduces new opportunities to study quantum many-body systems. In this paper, we show that quantum circuits can provide a dramatically more efficient representation than current classical numerics of the quantum states generated under nonequilibrium quantum dynamics. For quantum circuits, we perform both real- and imaginary-time evolution using an optimization algorithm that is feasible on near-term quantum computers. We benchmark the algorithms by finding the ground state and simulating a global quench of the transverse-field Ising model with a longitudinal field on a classical computer. Furthermore, we implement (classically optimized) gates on a quantum processing unit and demonstrate that our algorithm effectively captures real-time evolution.