Detalle Publicación

Quantum outage probability for time-varying quantum channels

Autores: Etxezarreta Martinez, Josu (Autor de correspondencia); Fuentes, P. (Autor de correspondencia); Crespo Bofill, Pedro (Autor de correspondencia); García-Frías, J. (Autor de correspondencia)
Título de la revista: PHYSICAL REVIEW, A
ISSN: 2469-9926
Volumen: 105
Número: 1
Páginas: 012432
Fecha de publicación: 2022
Recent experimental studies have shown that the relaxation time T-1 and the dephasing time T-2 of superconducting qubits fluctuate considerably over time. Time-varying quantum channel (TVQC) models have been proposed in order to consider the time-varying nature of the parameters that define qubit decoherence. This dynamic nature of quantum channels causes a degradation of the performance of quantum error correction codes (QECCs) that is portrayed as a flattening of their error rate curves. In this article we introduce the concepts of quantum outage probability and quantum hashing outage probability as asymptotically achievable error rates by a QECC with the quantum rate RQ operating over a TVQC. We derive closed-form expressions for the family of time-varying amplitude damping channels and study their behavior for different scenarios. We quantify the impact of time variation as a function of the relative variation of T-1 around its mean. We conclude that the performance of QECCs is limited in many cases by the inherent fluctuations of their decoherence parameters and corroborate that parameter stability is crucial to maintain the excellent performance observed over static quantum channels.