Squeezing-enhanced quantum key distribution over atmospheric channels

We propose the Gaussian continuous-variable quantum key distribution using squeezed states in the composite channels including atmospheric propagation with transmittance fluctuations. We show that adjustments of signal modulation and use of optimal feasible squeezing can be sufficient to significantly overcome the coherent-state protocol and drastically improve the performance of quantum key distribution in atmospheric channels, also in the presence of additional attenuating and noisy channels. Furthermore, we consider examples of atmospheric links of different lengths, and show that optimization of both squeezing and modulation is crucial for reduction of protocol downtime and increase of secure atmospheric channel distance. Our results demonstrate unexpected advantage of fragile squeezed states of light in the free-space quantum key distribution applicable in daylight and stable against atmospheric turbulence.Comment: 10 pages, 3 figure

An innovative solid liquid extraction technology: use of the naviglio extractor for the production of lemon liquor.

This document is a review on solid-liquid extractive techniques and describes an innovative solid-liquid extraction technology using the Naviglio Extractor®. Also explained is an application for the production of alcoholic extract from lemon peel. The alcoholic extract, mixed with a sugar and water solution in the right proportions is used to make a well known Italian lemon liquor commonly named "limoncello". Lemon liquor is obtained utilizing the Naviglio Extractor®; the procedure used is fast and efficient and uses about half the weight of lemon peel per volume of ethyl alcohol used for the extraction of the odorous and taste responsible compounds, compared to the commonly used extraction procedures. To test the consumer’s preference and compare the taste of the liquor obtained with that obtained by peel maceration from the same lot of lemons and obtained using the traditional recipe, a consumer test has been carried out. One hundred people, chosen from among frequent consumers of limoncello, tasted the two lemon liquors, and evaluated intensity of aroma, colour, alcohol taste and sweetness. In about 81% of the preferences, the liquor obtained using the Naviglio Extractor® was preferred. The extraction process used allows the ethanol from used up lemon peel to be totally recovered so that these can be disposed of as non toxic waste or used in agriculture or as cattle feed

Squeezing of Atoms in a Pulsed Optical Lattice

We study the process of squeezing of an ensemble of cold atoms in a pulsed optical lattice. The problem is treated both classically and quantum-mechanically under various thermal conditions. We show that a dramatic compression of the atomic density near the minima of the optical potential can be achieved with a proper pulsing of the lattice. Several strategies leading to the enhanced atomic squeezing are suggested, compared and optimized.Comment: Latex, 9 pages, 10 figures, submitted to PR

Multi-mode bosonic Gaussian channels

A complete analysis of multi-mode bosonic Gaussian channels is proposed. We clarify the structure of unitary dilations of general Gaussian channels involving any number of bosonic modes and present a normal form. The maximum number of auxiliary modes that is needed is identified, including all rank deficient cases, and the specific role of additive classical noise is highlighted. By using this analysis, we derive a canonical matrix form of the noisy evolution of n-mode bosonic Gaussian channels and of their weak complementary counterparts, based on a recent generalization of the normal mode decomposition for non-symmetric or locality constrained situations. It allows us to simplify the weak-degradability classification. Moreover, we investigate the structure of some singular multi-mode channels, like the additive classical noise channel that can be used to decompose a noisy channel in terms of a less noisy one in order to find new sets of maps with zero quantum capacity. Finally, the two-mode case is analyzed in detail. By exploiting the composition rules of two-mode maps and the fact that anti-degradable channels cannot be used to transfer quantum information, we identify sets of two-mode bosonic channels with zero capacity.Comment: 37 pages, 3 figures (minor editing), accepted for publication in New Journal of Physic