Mesoscopic atomic entanglement for precision measurements beyond the standard quantum limit

Squeezing of quantum fluctuations by means of entanglement is a well recognized goal in the field of quantum information science and precision measurements. In particular, squeezing the fluctuations via entanglement between two-level atoms can improve the precision of sensing, clocks, metrology, and spectroscopy. Here, we demonstrate 3.4 dB of metrologically relevant squeezing and entanglement for ~ 10^5 cold cesium atoms via a quantum nondemolition (QND) measurement on the atom clock levels. We show that there is an optimal degree of decoherence induced by the quantum measurement which maximizes the generated entanglement. A two-color QND scheme used in this paper is shown to have a number of advantages for entanglement generation as compared to a single color QND measurement.Comment: 6 pages+suppl, PNAS forma

International Risk Sharing and European Monetary Unification

We explore income and consumption smoothing patterns among European Community countries and among OECD countries during the period 1966-90. We find that for OECD as well as for EC countries about 40 percent of shocks to GDP are smoothed at the one year frequency, with about half the smoothing achieved through national government budget deficits and half by corporate saving. At the three year differencing frequency only 25 percent of shocks to GDP are smoothed, mainly via government lending and borrowing. In the absence of alternative income and consumption smoothing mechanisms, the restrictions on budget deficits imposed by the Maastricht Treaty should be relaxed to allow governments to run large temporary deficits in response to output shocks.Europe risk, international monetary system

Acceleration of heavy and light particles in turbulence: comparison between experiments and direct numerical simulations

We compare experimental data and numerical simulations for the dynamics of inertial particles with finite density in turbulence. In the experiment, bubbles and solid particles are optically tracked in a turbulent flow of water using an Extended Laser Doppler Velocimetry technique. The probability density functions (PDF) of particle accelerations and their auto-correlation in time are computed. Numerical results are obtained from a direct numerical simulation in which a suspension of passive pointwise particles is tracked, with the same finite density and the same response time as in the experiment. We observe a good agreement for both the variance of acceleration and the autocorrelation timescale of the dynamics; small discrepancies on the shape of the acceleration PDF are observed. We discuss the effects induced by the finite size of the particles, not taken into account in the present numerical simulations.Comment: 7 pages, 4 figure

On the Coexistence of Diagonal and off-Diagonal Long-Range Order, a Monte Carlo Study

The zero temperature properties of interacting 2 dimensional lattice bosons are investigated. We present Monte Carlo data for soft-core bosons that demonstrate the existence of a phase in which crystalline long-range order and off-diagonal long-range order (superfluidity) coexist. We comment on the difference between hard and soft-core bosons and compare our data to mean-field results that predict a larger coexistence region. Furthermore, we determine the critical exponents for the various phase transitions.Comment: 7 pages and 8 figures appended in postscript, KA-TFP-93-0

NOx AND SO2 EMISSIONS OF HUNGARIAN ELECTRIC POWER PLANT BOILERS

Coal fuelled power stations are responsible for about the half of SO2 emission in Hungary. Specific emission values may be 5 to 10 times the ultimate value admitted in the FRG. Introduction of various desulfurization attachment methods has to be endeavoured in coal fired power stations. The share of Hungarian power stations in NOx emission is some lower, about a quarter. The high specific NOx emission attributable to firing methods (construction) is of importance especially for gas firing. Introduction of (primary) firing methods has to be endeavoured, to prevent NOx formation

Adaptation of photosystem II to high and low light in wild-type and triazine-resistant Canola plants: analysis by a fluorescence induction algorithm

Plants of wild-type and triazine-resistant Canola (Brassica napus L.) were exposed to very high light intensities and after 1 day placed on a laboratory table at low light to recover, to study the kinetics of variable fluorescence after light, and after dark-adaptation. This cycle was repeated several times. The fast OJIP fluorescence rise curve was measured immediately after light exposure and after recovery during 1 day in laboratory room light. A fluorescence induction algorithm has been used for resolution and analysis of these curves. This algorithm includes photochemical and photo-electrochemical quenching release components and a photo-electrical dependent IP-component. The analysis revealed a substantial suppression of the photo-electrochemical component (even complete in the resistant biotype), a partial suppression of the photochemical component and a decrease in the fluorescence parameter Fo after high light. These effects were recovered after 1 day in the indoor light