Keeping quantum simple

Giulio Chiribella, Giacomo Mauro D’Ariano, Paolo Perinotti

David Peter Divincenzo, Patrick M. Hayden, Barbara M. Terhal

Recent work has shown how to use the laws of quantum mechanics to keep classical and quantum bits secret in a number of different circumstances. Among the examples are private quantum channels, quantum secret sharing and quantum data hiding. In this paper we show that a method for keeping two classical bits hidden in any such scenario can be used to construct a method for keeping one quantum bit hidden, and vice--versa. In the realm of quantum data hiding, this allows us to construct bipartite and multipartite hiding schemes for qubits from the previously known constructions for hiding bits. Our method also gives a simple proof that two bits of shared randomness are required to construct a private quantum channel hiding one qubit.

K. R. W. Jones

Using Weinberg's generalized nonlinear quantum dynamics [Ann. Phys. (N.Y.) 194, 336 (1989)], we propose a simple way to form an interpolative dynamical system that joins the classical and quantum regimes. By altering a dimensionless control parameter \ensuremath{\lambda}\ensuremath{\in}[0,1], one can smoothly metamorphose quantum evolution into classical evolution, keeping the Hilbert-space dimension and physical constants unchanged. The method suggests an approach to studies of dynamical chaos suppression in quantized classically chaotic systems.

Frances Saunders

David Finkelstein

Hervé Rigneault, Pascal Berto

Coherent Raman scattering processes such as coherent anti-Stokes Raman scattering and stimulated Raman scattering are described in a tutorial way keeping simple physical pictures and simple derivations. The simplicity of the presentation keeps however most of the key features of these coherent and resonant processes and their intimate relation with spontaneous Raman scattering. This tutorial provides a digest of introduction to the fundamental physics at work, and it does not focus on the numerous technological implementations; rather, it provides the concepts and the physical tools to understand the extensive literature in this field. The presentation is made simple enough for under-graduate students, graduate students, and newcomers with various scientific backgrounds.