Quantum state engineering of a Hubbard system with ultracold fermions

TL;DR

This paper demonstrates a novel quantum state engineering technique for creating strongly correlated fermionic states in a Hubbard model using ultracold atoms, enabling low-temperature quantum simulations.

Contribution

It introduces a new method for preparing low-entropy, antiferromagnetic states in a Fermi-Hubbard system via entropy redistribution and potential manipulation.

Findings

Successful creation of a strongly correlated many-body state

Observation of antiferromagnetic correlations below exchange energy

Increase in entropy likely due to many-body physics in the process

Abstract

Accessing new regimes in quantum simulation requires the development of new techniques for quantum state preparation. We demonstrate the quantum state engineering of a strongly correlated many-body state of the two-component repulsive Fermi-Hubbard model on a square lattice. Our scheme makes use of an ultralow entropy doublon band insulator created through entropy redistribution. After isolating the band insulator, we change the underlying potential to expand it into a half-filled system. The final many-body state realized shows strong antiferromagnetic correlations and a temperature below the exchange energy. We observe an increase in entropy, which we find is likely caused by the many-body physics in the last step of the scheme. This technique is promising for low-temperature studies of cold-atom-based lattice models.