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Main Authors: Kishony, Gilad, Elazari, Avi, Cohen, Ron, Gazit, Lior
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.28342
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author Kishony, Gilad
Elazari, Avi
Cohen, Ron
Gazit, Lior
author_facet Kishony, Gilad
Elazari, Avi
Cohen, Ron
Gazit, Lior
contents We introduce a low-overhead technique for quantum error mitigation based on post-selection using auxiliary qubit measurements. The method exploits the structural property that, in an error-free computation, auxiliary qubits are often expected to return to the zero state after use. By selectively measuring these qubits at carefully chosen points in the circuit, erroneous shots can be identified and discarded, improving result fidelity with minimal hardware overhead. To account for circuit noise, including measurement errors, we analyze the likelihood that a measurement outcome indicates a corrupted shot. This analysis is informed by the measurement's backward light cone, namely the set of circuit operations that could affect the outcome. Shots whose auxiliary measurement outcomes imply a corruption likelihood above a tunable threshold are rejected. Simulations show that the method reduces the false-negative rate by approximately 10% while discarding only approximately 1% of valid shots. The threshold controls the bias-variance tradeoff inherent to post-selection, allowing the method to be adapted to the fidelity and sampling requirements of different applications.
format Preprint
id arxiv_https___arxiv_org_abs_2605_28342
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Low-cost quantum error mitigation via auxiliary qubit return validation
Kishony, Gilad
Elazari, Avi
Cohen, Ron
Gazit, Lior
Quantum Physics
We introduce a low-overhead technique for quantum error mitigation based on post-selection using auxiliary qubit measurements. The method exploits the structural property that, in an error-free computation, auxiliary qubits are often expected to return to the zero state after use. By selectively measuring these qubits at carefully chosen points in the circuit, erroneous shots can be identified and discarded, improving result fidelity with minimal hardware overhead. To account for circuit noise, including measurement errors, we analyze the likelihood that a measurement outcome indicates a corrupted shot. This analysis is informed by the measurement's backward light cone, namely the set of circuit operations that could affect the outcome. Shots whose auxiliary measurement outcomes imply a corruption likelihood above a tunable threshold are rejected. Simulations show that the method reduces the false-negative rate by approximately 10% while discarding only approximately 1% of valid shots. The threshold controls the bias-variance tradeoff inherent to post-selection, allowing the method to be adapted to the fidelity and sampling requirements of different applications.
title Low-cost quantum error mitigation via auxiliary qubit return validation
topic Quantum Physics
url https://arxiv.org/abs/2605.28342