Linear optical quantum memory

Abstract

In quantum computing a very important problem is that of building a quantum memory. We show that by using new techniques from scalable linear optical quantum computing (LOQC), it is possible to make an all linear-optical quantum memory capable of storing the computational qubit indefinitely. The same approach can be used to make a simple quantum repeater. Recent work by our group has shown how linear optical quantum computing ideas, recently proposed by Knill, Laflamme, and Milburn, and also by Franson and co-workers, can be used to make a scalable quantum repeater [1]. However, this repeater still requires a quantum memory to operate, which apparently requires resources other than those required for linear optical quantum computing. In this presentation, we will explicitly show how to construct a quantum memory using only LOQC resources and employing a simple error correction code for photon loss. The result is a simple, scalable, quantum memory. The device can also be operated as a quantum repeater that is far simpler than our original proposal to implement.