Fault-tolerant Quantum Error Correction Using a Linear Array of Emitters

Abstract

We propose a fault-tolerant quantum error correction architecture consisting of a linear array of emitters and delay lines. In our scheme, a resource state for fault-tolerant quantum computation is generated by letting the emitters interact with a stream of photons and their neighboring emitters. Depending on the number of emitters ne, we study the effect of delay line errors in two regimes: when ne is a small constant of order unity and when ne scales with the code distance. Between these two regimes, the logical error rate steadily decreases as ne increases, from a scaling of exp⁡(−cη−1/2) to exp⁡(−c′η−1), where η is the error rate per unit length in the delay line, for some constants c,c′>0. We also carry out a detailed study of the break-even point and the fault-tolerance overhead. These studies suggest that the multi-emitter architecture, using the state-of-the-art delay lines, can be used to demonstrate error suppression, assuming other sources of errors are sufficiently small.