Relative multiplexing for minimising switching in linear-optical quantum computing

Abstract

Many existing schemes for linear-optical quantum computing (LOQC) depend on\nmultiplexing (MUX), which uses dynamic routing to enable near-deterministic\ngates and sources to be constructed using heralded, probabilistic primitives.\nMUXing accounts for the overwhelming majority of active switching demands in\ncurrent LOQC architectures. In this manuscript, we introduce relative\nmultiplexing (RMUX), a general-purpose optimization which can dramatically\nreduce the active switching requirements for MUX in LOQC, and thereby reduce\nhardware complexity and energy consumption, as well as relaxing demands on\nperformance for various photonic components. We discuss the application of RMUX\nto the generation of entangled states from probabilistic single-photon sources,\nand argue that an order of magnitude improvement in the rate of generation of\nBell states can be achieved. In addition, we apply RMUX to the proposal for\npercolation of a 3D cluster state in [PRL 115, 020502 (2015)], and we find that\nRMUX allows a 2.4x increase in loss tolerance for this architecture.\n