FAu LMQ Talk: Realizing Lattice Surgery on Two Distance-Three Repetition Codes with Superconducting Qubits

We are pleased to announce the FAU LMQ Talk on Wednesday, April 2nd, at 16:00, at the Department of Physics (HF), Staudtstraße 7, Erlangen. The talk, titled “Realizing Lattice Surgery on Two Distance-Three Repetition Codes with Superconducting Qubits” will be presented by Michael Kerschbaum from ETH Zurich.

This event is open to all and is organized and hosted by Christopher Eichler.

Abstract:

Quantum error correction is needed for quantum computers to be capable of fault-tolerantly executing algorithms using hundreds of logical qubits. Recent experiments have demonstrated subthreshold error rates for state preservation of a single logical qubit. In addition, the realization of universal quantum computation requires the implementation of logical entangling gates. Lattice surgery offers a practical approach for implementing such gates, particularly in planar quantum processor layouts. In this work, we demonstrate lattice surgery between two distance-three repetition-code qubits by splitting a single distance-three surface-code qubit. Using a quantum circuit fault-tolerant to bit-flip errors, we achieve an improvement in the value of the decoded ZZ logical two-qubit observable compared to a similar non-encoded circuit. By preparing the surface-code qubit in initial states parametrized by a varying polar angle, we evaluate the performance of the lattice surgery operation for non-cardinal states on the logical Bloch sphere and employ logical two-qubit tomography to reconstruct the Pauli transfer matrix of the operation. In this way, we demonstrate the functional building blocks needed for lattice surgery operations on larger-distance codes based on superconducting circuits.