Bright bichromatic entanglement and quantum dynamics of sum frequency generation

We investigate the quantum properties of the well-known process of sum frequency generation, showing that it is potentially a very useful source of non-classical states of the electromagnetic field, some of which are not possible with the more common techniques. We show that it can produce quadrature squeezed light, bright bichromatic entangled states and symmetric and asymmetric demonstrations of the Einstein-Podolsky-Rosen paradox. We also show that the semiclassical equations totally fail to describe the mean-field dynamics when the cavity is strongly pumped

THE DOUKHOBORS IN CANADA - CONFLICT AND SOCIAL CHANGE, 1900-1976

he present study will document the number of acts of violence carried out by the Doukhobors in Canada during the period 1900-1976 as well as assess the influence of two potentially important causal factors: (i) leadership style and (ii) stress and strain on the incidence of violence. While a great deal has been written on the Doukhobors, much of the material is of a “sensational” variety and lacks any serious analytical framework. Few researchers have tried to systematically document the actual number of conflicts engaged in by Doukhobors or relate these periodic episodes of conflict to potential causes

Quantum ultra-cold atomtronics

It is known that a semi-classical analysis is not always adequate for atomtronics devices, but that a fully quantum analysis is often necessary to make reliable predictions. While small numbers of atoms at a small number of sites are tractable using the density matrix, a fully quantum analysis is often not straightforward as the system becomes larger. We show that the fully quantum positive-P representation is then a viable calculational tool. We postulate an atomtronic phase-gate consisting of four wells in a Bose-Hubbard configuration, for which the semi-classical dynamics are controllable using the phase of the atomic mode in one of the wells. We show that the quantum predictions of the positive-P representation for the performance of this device have little relation to those found semi-classically, and that the performance depends markedly on the actual quantum states of the initially occupied modes. We find that initial coherent states lead to closest to classical dynamics, but that initial Fock states give results that are quite different. A fully quantum analysis also opens the door for deeply quantum atomtronics, in which properties such as entanglement and EPR (Einstein-Podolsky-Rosen) steering become valuable technical properties of a device.Comment: 12 pages, 6 figures, submitted to Phys. Rev

A quantum correlated twin atom laser from a Bose-Hubbard system

We propose and evaluate a method to construct a quantum correlated twin atom laser using a pumped and damped Bose-Hubbard inline trimer which can operate in a stationary regime. With pumping via a source condensate filling the middle well and damping using either an electron beam or optical means at the two end wells, we show that bipartite quantum correlations build up between the ends of the chain, and that these can be measured either in situ or in the outcoupled beams. While nothing similar to our system has yet been achieved experimentally, recent advances mean that it should be practically realisable in the near future.Comment: 15 pages, 8 figures, theory. Typos fixed and material added to introductio

Accounting for Multiplicity in Calculating Eta Earth

Using the updated exoplanet population parameters of our previous study, which includes the planetary radius updates from Gaia DR2 and an inferred multiplicity distribution, we provide a revised $\eta_{\oplus}$ calculation. This is achieved by sampling planets from our derived population model and determining which planets meet our criterion for habitability. To ensure robust results, we provide probabilities calculated over a range of upper radius limits. Our most optimistic criterion for habitability provides an $\eta_{\oplus}$ value of $0.34\pm 0.02 \frac{\rm planets}{\rm star}$. We also consider the effects of multiplicity and the number of habitable planets each system may contain. Our calculation indicates that $6.4\pm0.5\%$ of GK dwarfs have more than one planet within their habitable zone. This optimistic habitability criterion also suggests that $0.036\pm0.009\%$ of solar-like stars will harbor 5 or more habitable planets. These tightly packed highly habitable system should be extremely rare, but still possible. Even with our most pessimistic criterion we still expect that $1.8\pm0.2\%$ of solar-like stars harbor more than one habitable planet.Comment: 7 pages, 1 figure; Accepted for publication in MNRA