Year: 2024
Type: article
Abstract: An effective time-dependent Hamiltonian can be implemented by making a quantum system fly through an inhomogeneous potential, realizing, for example, a quantum gate on its internal degrees of freedom. However, flying systems have a spatial spread that will generically entangle the internal and spatial degrees of freedom, leading to decoherence in the internal state dynamics, even in the absence of any external reservoir. We provide formulas valid at all times for the dynamics, fidelity, and change of entropy for ballistic particles with small spatial spreads, quantified by Δx. This non-Markovian decoherence can be significant for ballistic flying qubits (scaling as Δx^{2}) but usually not for flying qubits carried by a moving potential well (scaling as Δx^{6}). We also discuss a method to completely counteract this decoherence for a ballistic qubit later measured.
Source: Physical Review Letters
Institutions: Centre National de la Recherche Scientifique, University of Trieste, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, The Abdus Salam International Centre for Theoretical Physics (ICTP), Chapman University, University of Rochester, Laboratoire de Physique et Modélisation des Milieux Condensés, Université Grenoble Alpes, Centre for Quantum Technologies, National University of Singapore, UMI MajuLab
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1190173965, G1693829329, G2243584955, G244262077, G3007892998, G424718656, Testing Quantum Thermodynamics with local Probes, From NISQ to LSQ: Bosonic and LDPC codes, thermoDynamics in Cavity Quantum ElectrodynamIcs, G7362232732, Quantum computers in the presence of resource constraints, G7436129674, G7438636020, Thermodynamics of Quantum Information: Engines, Measurement, and Entropy, G9487005
OpenAlex ID: W4377086424