Error suppression in adiabatic quantum computing with qubit ensembles

Abstract Incorporating protection against quantum errors into adiabatic computing (AQC) is an important task due to the inevitable presence of decoherence. Here, we investigate error-protected encoding AQC Hamiltonian, where qubit ensembles are used in place qubits. Our Hamiltonian only involves total spin operators ensembles, offering a simpler route towards error-corrected computing. scheme particularly suited neutral atomic gases it possible realize large ensemble sizes and produce ensemble-ensemble entanglement. We identify critical size N c nature first excited state becomes single particle perturbation ground state, gap energy predictable by mean-field theory. For larger than , protected logically equivalent states performance improves with as long decoherence rate sufficiently low.