Multiphoton quantum optics and quantum state engineering

Abstract

We present a review of theoretical and experimental aspects of multiphoton quantum optics. Multiphoton processes occur and are important for many aspects of matter–radiation interactions that include the efficient ionization of atoms and molecules, and, more generally, atomic transition mechanisms; system-environment couplings and dissipative quantum dynamics; laser physics, optical parametric processes, and interferometry.A single review cannot account for all aspects of such an enormously vast subject. Here we choose to concentrate our attention on parametric processes in nonlinear media, with special emphasis on the engineering of nonclassical states of photons and atoms that are relevant for the conceptual investigations as well as for the practical applications of forefront aspects of modern quantum mechanics. We present a detailed analysis of the methods and techniques for the production of genuinely quantum multiphoton processes in nonlinear media, and the corresponding models of multiphoton effective interactions. We review existing proposals for the classification, engineering, and manipulation of nonclassical states, including Fock states, macroscopic superposition states, and multiphoton generalized coherent states.We introduce and discuss the structure of canonical multiphoton quantum optics and the associated one- and two-mode canonical multiphoton squeezed states. This framework provides a consistent multiphoton generalization of two-photon quantum optics and a consistent Hamiltonian description of multiphoton processes associated to higher-order nonlinearities. Finally, we discuss very recent advances that by combining linear and nonlinear optical devices allow to realize multiphoton entangled states of the electromagnetic field, either in discrete or in continuous variables, that are relevant for applications to efficient quantum computation, quantum teleportation, and related problems in quantum communication and information

Information geometry of Gaussian channels

“…Progress in quantum information technology is bringing long-standing questions related to quantum channels to the front line of research. Topics such as dissipation-assisted quantum computation [1], quantum teleportation [2], quantum memories [3] and quantum state engineering [4,5] all have in common that they deal with quantum channels in one way or another. One major question that has recently received significant amount of attention is the definition of a distance among quantum channels [6][7][8].…”

Thermal state truncation by using quantum-scissors device

“…However, in the recent several decades, some probabilistic schemes are proposed to generate and manipulate non-Gaussian states [6][7][8]. Many schemes work in postselection [9], that is, the generated state is accepted conditionally on a measurement outcome.…”

Continuous-variable entanglement distillation and noncommutative central limit theorems

“…[22]) also provide a more direct source of non-Gaussian entangled photons. These are the most experimentally feasible means of non-Gaussian state preparation, but the potential advantage of exploiting more exotic forms of non-Gaussianity has also been considered [11,21,23,24]. The need for non-Gaussian operations extends beyond distillation problems, and they are required to violate locality [25][26][27] and to outperform classical computers [28][29][30][31][32].…”