Efficiently preparing chiral states via fermionic cooling on bosonic quantum hardware

TL;DR

This paper introduces an efficient method for preparing fermionic ground states, including topological phases, on noisy bosonic quantum hardware using adiabatic cooling with a simulated bath, improving scalability and noise resilience.

Contribution

The authors develop a novel protocol that enables efficient fermionic state preparation on bosonic quantum simulators, leveraging a local fermionic description and coherent hopping to the bath.

Findings

Achieves linear scaling of cooling rate with excitation density.

Successfully prepares topological phases like the Kitaev honeycomb model.

Performs well under noise, suitable for near-term devices.

Abstract

Simulating many-body systems is one of the most promising applications of near-term quantum computers. An important open question is how to efficiently prepare the ground states of arbitrary fermionic Hamiltonians, especially those with nontrivial topology. Here, we propose an efficient protocol for preparing low-energy states of fermionic Hamiltonians on a noisy bosonic quantum simulator by adiabatic cooling using a simulated bath. We arrange the couplings such that the simulated system and bath together obtain a local fermionic description in which fermionic excitations can be extracted individually, via coherent hopping to the bath, rather than in pairs as would otherwise be required by fermion parity conservation. This approach thus achieves a linear (rather than quadratic) scaling of the cooling rate vs. excitation density at low densities. We show that certain topological phases such as the chiral (non-Abelian) phase of the Kitaev honeycomb model can be prepared efficiently using our protocol. Our protocol performs favorably in the presence of noise, making it suitable for execution on near-term quantum devices.