Print Email Facebook Twitter Protecting quantum entanglement from leakage and qubit errors via repetitive parity measurements Title Protecting quantum entanglement from leakage and qubit errors via repetitive parity measurements Author Bultink, C.C. (TU Delft ALG/General; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) O'Brien, T. E. (Universiteit Leiden) Vollmer, R. (TU Delft Business Development; Kavli institute of nanoscience Delft) Muthusubramanian, N. (TU Delft QuTech Advanced Research Centre; TU Delft QCD/DiCarlo Lab; Kavli institute of nanoscience Delft) Beekman, M. W. (Kavli institute of nanoscience Delft; TNO; Student TU Delft) Rol, M.A. (TU Delft QCD/DiCarlo Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Fu, X. (TU Delft QCD/Almudever Lab; TU Delft QuTech Advanced Research Centre) Tarasinski, B.M. (TU Delft QCD/DiCarlo Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Ostroukh, V.P. (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Varbanov, B.M. (TU Delft QuTech Advanced Research Centre; TU Delft Applied Sciences; Kavli institute of nanoscience Delft) Bruno, A. (TU Delft QCD/DiCarlo Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) DiCarlo, L. (TU Delft QCD/DiCarlo Lab; TU Delft QN/DiCarlo Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Faculty Applied Sciences Department Business Development Date 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. To reference this document use: http://resolver.tudelft.nl/uuid:eabb1585-81b1-4c79-bcaa-7c833af0644e DOI https://doi.org/10.1126/sciadv.aay3050 ISSN 2375-2548 Source Science Advances, 6 (12) Part of collection Institutional Repository Document type journal article Rights © 2020 C.C. Bultink, T. E. O'Brien, R. Vollmer, N. Muthusubramanian, M. W. Beekman, M.A. Rol, X. Fu, B.M. Tarasinski, V.P. Ostroukh, B.M. Varbanov, A. Bruno, L. DiCarlo Files PDF eaay3050.full.pdf 617.37 KB Close viewer /islandora/object/uuid:eabb1585-81b1-4c79-bcaa-7c833af0644e/datastream/OBJ/view