Topics in Non-Linear Quantum Optics.

Shigeaki Uchida

This topical issue features optical quantum computer, OQC and its related technology developments. Every article describes fundamental aspects of OQC and quantum phenomena that OQC is based on. These include universal quantum computer based on quantum circuit model, quantum simulator, oneway quantum computer, fault tolerance, Boson sampling, squeezed state of photon, superposition, and entanglement. Much emphasis is laid on Linear Optical Quantum Computing for non-linear phase coupling between two photons which makes the technology very unique and gives advantages over other kinds of physical realization rather than optical. Alternative method of non-linear coupling has been realized by circuit QED with microwave photons.

Warren Nagourney

Nagourney provides a course in quantum electronics for researchers in atomic physics and other related areas (including telecommunications). The book covers the usual topics, such as Gaussian beams, optical cavities, lasers, non-linear optics, modulation techniques and fibre optics, but also includes a number of areas not usually found in a textbook on quantum electronics, such as the enhancement of non-linear processes in a build-up cavity or periodically poled waveguide, impedance matching into a cavity and astigmatism in ring cavities.

高志 近藤

Kazuhiko Misawa

Luigi A. Lugiato, A. Gatti, E. Brambilla +5 more

Abstract. The field of Quantum Imaging exploits the quantum nature of light and the intrinsic parallelism of optical signals to devise novel techniques for optical imaging and for parallel information processing at the quantum level (see [1] and references quoted therein). In this presentation, we will shortly discuss two topics in this area: the first is the so-called ghost imaging which, however, is not necessarily quantum; the second is the detection of faint amplitude objects with a sensitivity beyond the standard quantum limit, and in this case we are fully in the quantum domain. Both topics are related to the phenomenon of optical parametric down-conversion (PDC), in which a fraction of the pump photons of a laser beam, injected into a crystal with a quadratic non-linearity, are down-converted to a pair of signal and idler photons, with conservation of total energy and total momentum. A feature of paramount importance is that the signal and idler beams are spatially correlated both in the near field (position correlation) and in the far field (momentum correlation).The simultaneous presence of position and momentum correlation implies quantum entanglement, as it has been also observed experimentally [2]. 1. Ghost Imaging