A realistic experiment to demonstrate macroscopic quantum coherence

According to quantum theory, microscopic objects exist in a superposition of distinct states until they are “observed”. Nobody knows whether such quantum coherence can actually exist in a macroscopic system. In the experiment described here, a superconducting quantum interference device is extremely well isolated from any interaction with internal or external modes, and a superposition state can be demonstrated even if it lasts for less than 1 ns. This is accomplished by using superconducting digital electronic circuitry as the experimental apparatus. If successful, it is the first step toward a future full-scale quantum computer fabricated using integrated circuit manufacturing techniques.     

A proposed back action evading read-out for a gravitational wave detector

We propose a Back Action Evasion read out to improve the sensitivity of a capacitively coupled resonant transducer for gravitational wave detectors. We show that the noise can be reduced by factors 10 to 100 over the standard amplifier limit using detector parameters already achieved.     

Bounded regions of chaotic behavior in the control parameter space of a driven non-linear resonator

We have investigated the behavior of a driven non-linear electrical resonator over a large region of the control parameter space, i.e. the amplitude and frequency of the drive voltage. In addition to features characteristic of a one-dimensional non-invertible iterated map there exist isolated regions of chaotic behavior bounded by a Feigenbaum series of period-doubling bifurcations.     

Polydispersions radiation envelope: Influence of particle size and assumed distribution function

Summary The influence of polydispersity, particle size and of assumed distribution on angular dependence of theMie intensity functions in systems with relative refractive indexm = 1.10 was studied theoretically. Two distribution functions were used; Stevenson-Heller-Wallach (SHWD) and logarithmic distribution of negative order (NOLD). It was found, that for highly polydisperse systems the functional dependences obtain also undulative character. By means of NOLD the angular shift of extremes on the curves studied with increasing polydispersity was not observed. The application of this distribution in comparison with SHWD shows more structured angular scattering patterns with increasing particle size and this fact can also be employed in modelling and in distribution analysis of dispersion with higher degree of polydispersity.With 4 figures