title: Quantum Speed Limits for Leakage and Decoherence.
abstract: We introduce state-independent, nonperturbative Hamiltonian quantum speed limits for population leakage and fidelity loss, for a gapped open system interacting with a reservoir. These results hold in the presence of initial correlations between the system and the reservoir, under the sole assumption that their interaction and its commutator with the reservoir Hamiltonian are norm bounded. The reservoir need not be thermal and can be time dependent. We study the significance of energy mismatch between the system and the local degrees of freedom of the reservoir that directly interact with the system. We demonstrate that, in general, by increasing the system gap we may reduce this energy mismatch, and, consequently, drive the system and the reservoir into resonance; this can accelerate fidelity loss, irrespective of the thermal properties or state of the reservoir. This implies that quantum error suppression strategies based on increasing the gap are not uniformly beneficial. Our speed limits also yield an elementary lower bound on the relaxation time of spin systems.
authors.affiliation: Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089, USA.|Department of Physics, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Iman
authors.initials: I
authors.lastname: Marvian
authors.affiliation: Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089, USA.|Department of Physics, University of Southern California, Los Angeles, California 90089, USA.|Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.|Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Lidar