Decoherence-free states protect quantum information from collective noise, the predominant cause of decoherence in current implementations of quantum communication and computation. Here we demonstrate that spontaneous parametric down conversion can be used to generate four-photon states which enable the encoding of one qubit in a decoherence-free subspace. The immunity against noise is verified...

Entanglement is essential to many quantum information applications, but it is easily destroyed by quantum decoherence arising from interaction with the environment. We report the first experimental demonstration of an entanglement-based protocol that is resilient to loss and noise which destroy entanglement. Specifically, despite channel noise 8.3 dB beyond the threshold for entanglement breaki...

Nonlinear spectral associative memories are proposed as quantized frequency domain formulations of nonlinear, recurrent associative memories in which volatile network attractors are instantiated by attractor waves. In contrast to conventional associative memories, attractors encoded in the frequency domain by convolution may be viewed as volatile online inputs, rather than nonvolatile, off-line...

background : the recognition of road traffic noise as one of the main sources of environmental pollution has led to develop models that enable to predict noise level from fundamental variables. traffic noise prediction models are required as aids for designing roads and highways. in addition, sometimes are used in the assessment of existing or envisaged changes in traffic noise conditions. in t...

Acoustic source localization system for speech signals based on five microphone array was developed. Three dimensional position computation is based on time delay estimation between pairs of microphones. The psyhoacoustically motivated voice activity detector was used to robustly determine activity of speaker in presence of background noise. The detector was based on modulation properties of hu...

Automated fringe-pattern processing is important in a great number of industrial applications, such as optical data testing and quality control. One of the main problems that arises with these processes is the automated phase unwrapping of the phase map associated with the fringe pattern. Usually the phase map presents problems such as noise, and low-modulation areas. A new phase-unwrapping alg...

In image processing, edge detection often makes use of integer-order di erentiation operators, especially order 1 used by the gradient and order 2 by the Laplacian. This paper demonstrates how introducing an edge detector based on non-integer (fractional) di erentiation can improve the criterion of thin detection, or detection selectivity in the case of parabolic luminance transitions, and the ...