Variational quantum state preparation via quantum data buses

TL;DR

This paper introduces a variational quantum algorithm for efficiently preparing ground states of 1D lattice Hamiltonians on quantum devices with qubit interactions mediated by Quantum Data Buses, particularly in ion trap systems.

Contribution

It presents a novel variational approach tailored for quantum devices with Quantum Data Buses, enabling scalable and decoherence-resistant ground state preparation.

Findings

Successful numerical simulation of the Su-Schrieffer-Heeger model ground state

The method is scalable and tolerant to finite COM mode temperatures

Disentangling of the QDB occurs naturally during optimization

Abstract

We propose a variational quantum algorithm to prepare ground states of 1D lattice quantum Hamiltonians specifically tailored for programmable quantum devices where interactions among qubits are mediated by Quantum Data Buses (QDB). For trapped ions with the axial Center-Of-Mass (COM) vibrational mode as single QDB, our scheme uses resonant sideband optical pulses as resource operations, which are potentially faster than off-resonant couplings and thus less prone to decoherence. The disentangling of the QDB from the qubits by the end of the state preparation comes as a byproduct of the variational optimization. We numerically simulate the ground state preparation for the Su-Schrieffer-Heeger model in ions and show that our strategy is scalable while being tolerant to finite temperatures of the COM mode.