Capacity estimation and verification of quantum channels with arbitrarily correlated errors

Corsin Pfister, M. Adriaan Rol, Atul Mantri, Marco Tomamichel, Stephanie Wehner*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)
25 Downloads (Pure)


The central figure of merit for quantum memories and quantum communication devices is their capacity to store and transmit quantum information. Here, we present a protocol that estimates a lower bound on a channel's quantum capacity, even when there are arbitrarily correlated errors. One application of these protocols is to test the performance of quantum repeaters for transmitting quantum information. Our protocol is easy to implement and comes in two versions. The first estimates the one-shot quantum capacity by preparing and measuring in two different bases, where all involved qubits are used as test qubits. The second verifies on-the-fly that a channel's one-shot quantum capacity exceeds a minimal tolerated value while storing or communicating data. We discuss the performance using simple examples, such as the dephasing channel for which our method is asymptotically optimal. Finally, we apply our method to a superconducting qubit in experiment.

Original languageEnglish
Article number27
Number of pages9
JournalNature Communications
Issue number1
Publication statusPublished - 1 Dec 2018


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