35,483 research outputs found
Generations of orthogonal surface coordinates
Two generation methods were developed for three dimensional flows where the computational domain normal to the surface is small. With this restriction the coordinate system requires orthogonality only at the body surface. The first method uses the orthogonal condition in finite-difference form to determine the surface coordinates with the metric coefficients and curvature of the coordinate lines calculated numerically. The second method obtains analytical expressions for the metric coefficients and for the curvature of the coordinate lines
Non-Gaussian distribution of collective operators in quantum spin chains
We numerically analyse the behavior of the full distribution of collective
observables in quantum spin chains. While most of previous studies of quantum
critical phenomena are limited to the first moments, here we demonstrate how
quantum fluctuations at criticality lead to highly non-Gaussian distributions
thus violating the central limit theorem. Interestingly, we show that the
distributions for different system sizes collapse after scaling on the same
curve for a wide range of transitions: first and second order quantum
transitions and transitions of the Berezinskii-Kosterlitz-Thouless type. We
propose and carefully analyse the feasibility of an experimental reconstruction
of the distribution using light-matter interfaces for atoms in optical lattices
or in optical resonators.Comment: 15 pages, 5 figures; last version close to published versio
Deceleration of the solar wind in the Earth foreshock region: ISEE 2 and IMP 8 observations
The deceleration of the solar wind in the region of the interplanetary space filled by ions backstreaming from the Earth bow shock was studied using a two spacecraft technique. This deceleration, which is correlated with the "diffuse" but not with the "reflected" ion population, depends on the solar wind bulk velocity: at low velocities (below 300 km/sec) the velocity decrease is about 5 km/sec, while at higher velocities (above 400 km/sec) the decrease may be as large as 30 km/sec. Along with this deceleration, the solar wind undergoes a deflection of about 1 deg away from the direction of the Earth bow shock. The energy balance shows that the kinetic energy loss far exceeds the thermal energy which is possibly gained by the solar wind, therefore, at least part of this energy must go into waves and/or into the backstreaming ions
Learning styles inventories: an update of coffield, moseley, hall, & ecclestone`s reliability and validity matrix
Short-Range Ordered Phase of the Double-Exchange Model in Infinite Dimensions
Using dynamical mean-field theory, we have evaluated the magnetic
instabilities and T=0 phase diagram of the double-exchange model on a Bethe
lattice in infinite dimensions. In addition to ferromagnetic (FM) and
antiferromagnetic (AF) phases, we also study a class of disordered phases with
magnetic short-range order (SRO). In the weak-coupling limit, a SRO phase has a
higher transition temperature than the AF phase for all fillings p below 1 and
can even have a higher transition temperature than the FM phase. At T=0 and for
small Hund's coupling J_H, a SRO state has lower energy than either the FM or
AF phases for 0.26\le p 0 limit
but appears for any non-zero value of J_H.Comment: 11 pages, 3 figures, published versio
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