Title
Protecting quantum entanglement from leakage and qubit errors via repetitive parity measurements
Author
Bultink, C.C.
O'Brien, T.E.
Vollmer, R.
Muthusubramanian, N.
Beekman, M.W.
Rol, M.A.
Fu, X.
Tarasinski, B.
Ostroukh, V.
Varbanov, B.
Bruno, A.
DiCarlo, L.
Publication year
2020
Abstract
Protecting quantum information from errors is essential for large-scale quantum computation. Quantum error correction (QEC) encodes information in entangled states of many qubits and performs parity measurements to identify errors without destroying the encoded information. However, traditional QEC cannot handle leakage from the qubit computational space. Leakage affects leading experimental platforms, based on trapped ions and superconducting circuits, which use effective qubits within many-level physical systems. We investigate how two-transmon entangled states evolve under repeated parity measurements and demonstrate the use of hidden Markov models to detect leakage using only the record of parity measurement outcomes required for QEC. We show the stabilization of Bell states over up to 26 parity measurements by mitigating leakage using postselection and correcting qubit errors using Pauli-frame transformations. Our leakage identification method is computationally efficient and thus compatible with real-time leakage tracking and correction in larger quantum processors.
Subject
Error correction
Hidden Markov models
Quantum optics
Qubits
Trapped ions
To reference this document use:
http://resolver.tudelft.nl/uuid:b558cb67-103a-48d3-b3ea-1b0fbd29559b
DOI
https://doi.org/10.1126/sciadv.aay3050
TNO identifier
875530
Publisher
American Association for the Advancement of Science AAAS
ISSN
2375-2548
Source
Science Advances, 6 (6)
Document type
article