we study entanglement and squeezing of a cluster of spin systems under the influence of the two-axis countertwisting hamiltonian. the squeezing parameters given by wineland et al and also by kitagawa et al. are chosen as the criteria of spin squeezing. the criterion of pairwise entanglement is chosen to be the concurrence and that of the bipartite entanglement the linear entropy. we also define...

The entropy of the observable universe is increasing. Thus, at earlier times the entropy was lower. However, the cosmic microwave background radiation reveals an apparently high entropy universe close to thermal and chemical equilibrium. A two-part solution to this cosmic initial entropy problem is proposed. Following Penrose, we argue that the evenly distributed matter of the early universe is...

Wear is a complicated phenomenon caused by the relative movement of two contacting surfaces compressed together by a normal force. Prediction of the wear, in most cases, requires various experiments and microstructural characterization of the contacting surfaces. Mathematical models based on physical concepts could provide considerable help in understanding the physical behavior and hence the p...

Wear is a complicated phenomenon caused by the relative movement of two contacting surfaces compressed together by a normal force. Prediction of the wear, in most cases, requires various experiments and microstructural characterization of the contacting surfaces. Mathematical models based on physical concepts could provide considerable help in understanding the physical behavior and hence the p...

Ultrasound backscattering signals depend on the microstructures of tissues. Some studies have applied Shannon entropy to analyze the uncertainty of raw radiofrequency (RF) data. However, we found that the sensitivity of entropy in detecting various scatterer concentrations is limited; thus, we propose a weighted entropy as a new information entropy-based approach to enhance the performance of s...

In the present study, an analytical investigation on the entropy generation examination for viscoelastic fluid flow involving inclined magnetic field and non-linear thermal radiation aspects with the heat source and sink over a stretching sheet has been done. The boundary layer governing partial differential equations were converted in terms of appropriate similarity transformations to non-line...

Estimation of Shannon and Rényi entropies of unknown discrete distributions is a fundamental problem in statistical property testing and an active research topic in both theoretical computer science and information theory. Tight bounds on the number of samples to estimate these entropies have been established in the classical setting, while little is known about their quantum counterparts. In t...