RQC Seminar

295th RQC Seminar

• Speaker

  Dr. Shin Nishio
  ( University College London )

• Date

  13:00-14:00, (1:00 p.m.-2:00 p.m.) Thursday, July 23, 2026

• Venue

  Hybrid(Zoom, Cooperation Center 4F W426, Wako Campus/ 和光地区 研究交流棟4階 W426 (S41)）

• Title

  Qubit Loss Inference with Stabilizer Codes without Leakage Detection Units

• Inquiries

  yasunari.suzuki[at]riken.jp

Abstract
Quantum systems are subject to various kinds of noise, among which qubit loss can be particularly damaging for neutral atoms and trapped ions. Unlike erasure errors, loss errors are not heralded, making them more difficult to decode and correct. Many existing protocols convert loss errors into erasure errors using a quantum circuit called leakage detection unit (LDU). However, LDUs introduce additional space-time overhead and can themselves become a source of errors. To avoid using LDUs, We first derive a condition for detectable qubit-loss events using only syndrome-extraction outcomes and formulate the corresponding loss-inference problem. We also show that this problem can be relaxed to the minimum set cover problem. We then propose a protocol that performs loss inference without relying on LDUs. We evaluate the logical error rates of the proposed protocol and find that it outperforms an LDU-based approach under realistic error parameters for trapped-ion systems.