Fault-tolerant interface between quantum memories and quantum processors

TL;DR

This paper introduces subsystem lattice surgery, a practical method enabling fault-tolerant transfer of quantum information between different topological quantum codes using only local interactions, facilitating integration of quantum memories and processors.

Contribution

It proposes subsystem lattice surgery, a new technique for fault-tolerant code switching with only two-body interactions, enhancing quantum memory and processor interoperability.

Findings

Enables fault-tolerant transfer between topological codes

Uses only two-body nearest neighbor interactions

Facilitates quantum memory and processor integration

Abstract

Topological error correction codes are promising candidates to protect quantum computations from the deteriorating effects of noise. While some codes provide high noise thresholds suitable for robust quantum memories, others allow straightforward gate implementation needed for data processing. To exploit the particular advantages of different topological codes for fault-tolerant quantum computation, it is necessary to be able to switch between them. Here we propose a practical solution, subsystem lattice surgery, which requires only two-body nearest neighbor interactions in a fixed layout in addition to the indispensable error correction. This method can be used for the fault-tolerant transfer of quantum information between arbitrary topological subsystem codes in two dimensions and beyond. In particular, it can be employed to create a simple interface, a quantum bus, between noise resilient surface code memories and flexible color code processors.