References & Citations
Quantum Physics
Title: Characterization of errors in a CNOT between surface code patches
(Submitted on 8 May 2024 (v1), last revised 21 May 2024 (this version, v2))
Abstract: As current experiments already realize small quantum circuits on error corrected qubits, it is important to fully understand the effect of physical errors on the logical error channels of these fault-tolerant circuits. Here, we investigate a lattice-surgery-based CNOT operation between two surface code patches under phenomenological error models. (i) For two-qubit logical Pauli measurements -- the elementary building block of the CNOT -- we optimize the number of stabilizer measurement rounds, usually taken equal to $d$, the size (code distance) of each patch. We find that the optimal number can be greater or smaller than $d$, depending on the rate of physical and readout errors, and the separation between the code patches. (ii) We fully characterize the two-qubit logical error channel of the lattice-surgery-based CNOT. We find a symmetry of the CNOT protocol, that results in a symmetry of the logical error channel. We also find that correlations between X and Z errors on the logical level are suppressed under minimum weight decoding.
Submission history
From: Áron Márton [view email][v1] Wed, 8 May 2024 18:11:21 GMT (4120kb,D)
[v2] Tue, 21 May 2024 09:36:48 GMT (4221kb,D)
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