Emergence of classical behavior from the quantum spin

Classical Hamiltonian system of a point moving on a sphere of fixed radius is shown to emerge from the constrained evolution of quantum spin. The constrained quantum evolution corresponds to an appropriate coarse-graining of the quantum states into equivalence classes, and forces the equivalence classes to evolve as single units representing the classical states. The coarse-grained quantum spin with the constrained evolution in the limit of the large spin becomes indistinguishable from the classical system

The Geometry of Warped Product Singularities

In this article the degenerate warped products of singular semi-Riemannian manifolds are studied. They were used recently by the author to handle singularities occurring in General Relativity, in black holes and at the big-bang. One main result presented here is that a degenerate warped product of semi-regular semi-Riemannian manifolds with the warping function satisfying a certain condition is a semi-regular semi-Riemannian manifold. The connection and the Riemann curvature of the warped product are expressed in terms of those of the factor manifolds. Examples of singular semi-Riemannian manifolds which are semi-regular are constructed as warped products. Applications include cosmological models and black holes solutions with semi-regular singularities. Such singularities are compatible with a certain reformulation of the Einstein equation, which in addition holds at semi-regular singularities too.Comment: 14 page

REPRODUCTIVE PARAMETERS OF THOROUGHBRED MARES IN CROATIA

For the purpose of gaining better cognition on Thoroughbred breeding in Croatia, reproductive parameters of 87 Thoroughbred mares were analyzed. An average age of the first covering and foaling were 5.9 and 6.6 years, respectively. The average gestation length was 341.1 days and the most frequent foaling period (20.2% of foalings) was recorded between 336 to 340 days of gestation. Prolonged gestation period (p<0.05) was determined in colts. The gestation length was the longest in January (344.4 days) and the shortest in July (324.0 days). Between the gestation length and the age of the mare no significant correlation was found. There was a trend of foaling rate decreasing in mares older than 11 years. The highest number of successively registered foalings with 10 live born foals was observed on 2 individual samples. The greatest number of foalings occurred in April (30.9%), whilst there was no foaling in October. The genders were 50.6% male and 49.4% female foals. The incidence of abortions was 7.3%. Although indicators point to the breeding strategy heading towards the right direction, by educating the owners and with frequent veterinary supervision, especially for twin reduction, the reproductive performance could be enhanced

Gaussian-Induced Rotation in Triangular Photonic Lattices

Time-dependent rotation of counterpropagating mutually incoherent self-trapped Gaussian beams in periodic optically induced fixed photonic lattices is numerically investigated. Rotation occurs for some values of control parameters. For parameters of such rotation, the solitonic solutions are found using modified Petviashvili's method. It is shown that they correspond to the lowest values of propagation constant in the power diagrams and relation between observed rotation and less confined discrete solitonic solutions are demonstrated

Gaussian-Induced Rotation in Triangular Photonic Lattices

Time-dependent rotation of counterpropagating mutually incoherent self-trapped Gaussian beams in periodic optically induced fixed photonic lattices is numerically investigated. Rotation occurs for some values of control parameters. For parameters of such rotation, the solitonic solutions are found using modified Petviashvili's method. It is shown that they correspond to the lowest values of propagation constant in the power diagrams and relation between observed rotation and less confined discrete solitonic solutions are demonstrated