Real- and Imaginary-Time Evolution with Compressed Quantum Circuits

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.

Automated summary

The current generation of noisy intermediate-scale quantum computers introduces new opportunities for studying quantum many-body systems. It is shown in this paper that quantum circuits can provide a more efficient representation of quantum states generated under nonequilibrium quantum dynamics compared to current classical numerics. By benchmarking algorithms on classical computers and implementing (classically optimized) gates on a quantum processing unit, the authors demonstrate the effectiveness of their algorithm in capturing real-time evolution.