Acceleration statistics in thermally driven superfluid turbulence

New methods of flow visualization near absolute zero have opened the way to directly compare quantum turbulence (in superfluid helium) to classical turbulence (in ordinary fluids such as air or water) and explore analogies and differences. We present results of numerical simulations in which we examine the statistics of the superfluid acceleration in thermal counterflow. We find that, unlike the velocity, the acceleration obeys scaling laws similar to classical turbulence, in agreement with a recent quantum turbulence experiment of La Mantia et al.Comment: 5 pages, 5 figures, to appear in PR

Interaction of European Carbon Trading and Energy Prices

This paper addresses the economic impact of the EU Emission Trading Scheme for carbon on wholesale electricity and gas prices. Specifically, we analyse the mutual relationships between electricity, gas and carbon prices in the daily spot markets in the United Kingdom. Using a structural co-integrated VAR model, we show how the prices of carbon and gas jointly influence the equilibrium price of electricity. Furthermore, we derive the dynamic pass-trough of carbon into electricity price and the response of electricity and carbon prices to shocks in the gas price.Carbon Emission Trading, Energy Markets, Structural VECM

Implementation of a three-qubit quantum error correction code in a cavity-QED setup

The correction of errors is of fundamental importance for the development of contemporary computing devices and of robust communication protocols. In this paper we propose a scheme for the implementation of the three-qubit quantum repetition code, exploiting the interaction of Rydberg atoms with the quantized mode of a microwave cavity field. Quantum information is encoded within two circular Rydberg states of the atoms and encoding and decoding process are realized within two separate microwave cavities. We show that errors due to phase noise fluctuations could be efficiently corrected using a state-of-the-art apparatus.Comment: 9 pages, 5 figures. This is v2. Some misprints corrected, conclusions section extended, refs added. Accepted for publication on PR

Thermal effects on chaotic directed transport

We study a chaotic ratchet system under the influence of a thermal environment. By direct integration of the Lindblad equation we are able to analyze its behavior for a wide range of couplings with the environment, and for different finite temperatures. We observe that the enhancement of the classical and quantum currents due to temperature depend strongly on the specific properties of the system. This makes difficult to extract universal behaviors. We have also found that there is an analogy between the effects of the classical thermal noise and those of the finite $\hbar$ size. These results open many possibilities for their testing and implementation in kicked BECs and cold atoms experiments.Comment: 5 pages, 4 figure

THE DEMAND FOR FLUID MILK PRODUCTS IN THE U.S.: A DEMAND SYSTEMS APPROACH

The demand for fluid milk products has changed dramatically in recent years not only in terms of lower levels consumed but also in terms of the composition of the products consumed. A time-series based demand system analysis of the market for lowfat and whole milk products is developed incorporating the effects of changes in prices and demographic characteristics. From the estimated model, the impacts of future changes in the demographic profile of the U.S. population on fluid milk demand are analyzed.Demand and Price Analysis, Livestock Production/Industries,

Graviton propagator from background-independent quantum gravity

We study the graviton propagator in euclidean loop quantum gravity, using the spinfoam formalism. We use boundary-amplitude and group-field-theory techniques, and compute one component of the propagator to first order, under a number of approximations, obtaining the correct spacetime dependence. In the large distance limit, the only term of the vertex amplitude that contributes is the exponential of the Regge action: the other terms, that have raised doubts on the physical viability of the model, are suppressed by the phase of the vacuum state, which is determined by the extrinsic geometry of the boundary.Comment: 6 pages. Substantially revised second version. Improved boundary state ansat

Self-assembly and two-dimensional spontaneous resolution of cyano-functionalized [7]helicenes on Cu111

Birds of a feather flock together: STM and DFT studies provide the first example of spontaneous chiral resolution of a helicene on a surface. Racemic 6,13-dicyano[7]helicene forms fully segregated domains of pure enantiomers (2D conglomerate) on Cu(111). The propensity of the system to optimize intermolecular CN⋅⋅⋅HC(Ar) hydrogen bonding and CN⋅⋅⋅CN dipolar interactions translates into chiral recognition with preferential assembly of homochiral molecules