TY  - JOUR
AU  - Battistel, F.
AU  - Varbanov, B. M.
AU  - Terhal, B. M.
TI  - Hardware-Efficient Leakage-Reduction Scheme for Quantum Error Correction with Superconducting Transmon Qubits
JO  - PRX quantum
VL  - 2
IS  - 3
SN  - 2691-3399
CY  - College Park, MD
PB  - American Physical Society
M1  - FZJ-2021-06175
SP  - 030314
PY  - 2021
AB  - Leakage outside of the qubit computational subspace poses a threatening challenge to quantum error correction (QEC). We propose a scheme using two leakage-reduction units (LRUs) that mitigate these issues for a transmon-based surface code, without requiring an overhead in terms of hardware or QEC-cycle time as in previous proposals. For data qubits, we consider a microwave drive to transfer leakage to the readout resonator, where it quickly decays, ensuring that this negligibly disturbs the computational states for realistic system parameters. For ancilla qubits, we apply a |1⟩↔|2⟩π pulse conditioned on the measurement outcome. Using density-matrix simulations of the distance-3 surface code, we show that the average leakage lifetime is reduced to almost one QEC cycle, even when the LRUs are implemented with limited fidelity. Furthermore, we show that this leads to a significant reduction of the logical error rate. This LRU scheme opens the prospect for near-term scalable QEC demonstrations.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000680528300001
DO  - DOI:10.1103/PRXQuantum.2.030314
UR  - https://juser.fz-juelich.de/record/904605
ER  -