Frequency and temporal effects in linear optical quantum computing

Typically linear optical quantum computing (LOQC) models assume that all input photons are completely indistinguishable. In practice there will inevitably be non-idealities associated with the photons and the experimental setup which will introduce a degree of distinguishability between photons. We consider a non-deterministic optical controlled-NOT gate, a fundamental LOQC gate, and examine the effect of temporal and spectral distinguishability on its operation. We also consider the effect of utilizing non-ideal photon counters, which have finite bandwidth and time response.Comment: 10 pages, 9 figures, replaced with published versio

Modeling photo-detectors in quantum optics

Photo-detection plays a fundamental role in experimental quantum optics and is of particular importance in the emerging field of linear optics quantum computing. Present theoretical treatment of photo-detectors is highly idealized and fails to consider many important physical effects. We present a physically motivated model for photo-detectors which accommodates for the effects of finite resolution, bandwidth and efficiency, as well as dark-counts and dead-time. We apply our model to two simple well known applications, which illustrates the significance of these characteristics.Comment: 8 pages, 7 figure