Quantum counterdiabatic driving with local control

TL;DR

This paper develops and experimentally demonstrates local counterdiabatic driving protocols that enable efficient quantum state preparation without requiring detailed spectral information, using a trapped-ion system up to 14 qubits.

Contribution

It introduces a novel local counterdiabatic protocol with optimization that does not need spectral gap knowledge, and enhances it with a simple local control scheme, validated experimentally.

Findings

Effective state preparation up to 14 qubits

Protocols do not require spectral gap knowledge

Enhanced performance with local control methods

Abstract

Suppression of diabatic transitions in quantum adiabatic evolution stands as a significant challenge for ground state preparations. Counterdiabatic driving has been proposed to compensate for diabatic losses and achieve shortcut to adiabaticity. However, its implementation necessitates the generation of adiabatic gauge potential, which requires knowledge of the spectral gap of instantaneous Hamiltonians and involves highly non-local drivings in many-body systems. In this work, we consider local counterdiabatic (LCD) driving with approximate adiabatic gauge potential. Using transverse-field Ising model as an example, we present an in-depth study of the performance and optimization of LCD protocols. We then propose a novel two-step protocol based on LCD and simple local single-body control to further improve the performance. The optimization of these LCD-based protocols does not require knowledge of instantaneous Hamiltonians, and only additional local driving is involved. To benchmark the performance of LCD and the proposed local control-enhanced LCD technique, we experimentally implement digitized adiabatic quantum evolution in a trapped-ion system. We characterize the quality of the prepared states and explore the scaling behavior with system size up to 14 qubits. Our demonstration of quantum shortcut to adiabaticity opens a path towards preparing ground states of complex systems with accessible local controls.