Dependence of the slip coefficient on the form of the collision frequencySpringer Science and Business Media LLC - Tập 57 - Trang 297-306 - 2015
C. Cercignani, P. Foresti, F. Sernagiotto
The slip coefficient for a gas is computed for certain typical forms of the collision frequency. The computations are made by a numerical quadrature based on an exact formula and also by a variational procedure. There is a good agreement between the results obtained by both methods and between them and previously known results. Our calculations confirm that the slip coefficient is only slightly mo...... hiện toàn bộ
Quaternionic formulation of tachyons, superluminal transformations and a complex space-timeSpringer Science and Business Media LLC - Tập 50 - Trang 271-293 - 2007
K. Imaeda
A theory of tachyons and superluminal transformations is developed on the basis of the quaternionic formulation. We have introduced a complex space-time and a complex transformation group which contains both Lorentz transformations and superluminal transformations. The complex space-time «the biquaternion space» which is closed under the superluminal transformations is introduced. The principle of...... hiện toàn bộ
The origin of charge density waves in the 2H-polytypes of the group-V layer compoundsSpringer Science and Business Media LLC - Tập 38 - Trang 544-551 - 2007
N. J. Doran, G. Wexler, V. Heine, B. Riccò
The group-V metallic layer compounds exhibit superconductivity at low temperatures and all (except NbS2) undergo phase changes due to the formation of CDW at certain temperatures. In order to understand this theoretically, the electronic susceptibility is calculated and the electron-phonon interaction estimated. The susceptibility is computed directly from the band structure, for the example, of N...... hiện toàn bộ
Unitary squeezing operatorsU andW in the Schrödinger and Heisenberg picturesSpringer Science and Business Media LLC - Tập 108 - Trang 33-43 - 2008
E. Vlahos, A. Jannussis
We study the unitary operatorsU andW, which have been recently introduced by Fan Hong-Yi and describe squeezed states. The corresponding Hamilton operators in the Schrödinger picture have a continuous or discrete eigenvalue spectrum, depending on the values of two free parameters. The study in the Heisenberg picture is simple in the case where the parameters are time dependent. Finally, we study a...... hiện toàn bộ
General covariance and the isotropy of inertiaSpringer Science and Business Media LLC - Tập 35 - Trang 110-116 - 2007
H. Yilmaz
In this paper the oft confused issues of general covariance, correspondence and inertial isotropy are re-examined. This is done in terms of a generalized theory of gravity, which contains general relativity as a special case. It is shown that, when formulated in a manifestly covariant manner, the generalized theory leads to some second-order effects which are testable by experiment.
Gravitational matter-antimatter asymmetry and four-dimensional Yang-Mills gauge symmetrySpringer Science and Business Media LLC - Tập 61 - Trang 249-264 - 2007
J. P. Hsu
A formulation of gravity based on the maximum fourdimensional Yang-Mills gauge symmetry is studied. The theory predicts that the gravitational force inside matter (fermions) is different from that inside antimatter. This difference could lead to the cosmic separation of matter and antimatter in the evolution of the Universe. Moreover, a new gravitational long-range spin-force between two fermions ...... hiện toàn bộ
Angular-momentum reduction of the faddeev equationsSpringer Science and Business Media LLC - Tập 61 - Trang 403-410 - 2015
R. Balian, E. Brézin
Angular-momentum reduction of the Faddeev equations is re-examined. The symmetrical and unsymmetrical coupling schemes are directly related. A simpler explicit form is proposed, from which it appears that the number of coupled amplitudes has been overestimated. A sign oversight, relevant for calculating states with nonzero orbital momentum, is pointed out in some previous treatments.
The diffusion of weakly interacting particles from the proto-neutron starSpringer Science and Business Media LLC - Tập 105 - Trang 835-844 - 2007
Jewan Kim
The energy release of the proto-neutron star by the diffusion of the neutrinos and the majoron-like particles is discussed. It is shown that the majoron neutrino coupling is constrained from the observed neutrino flux from SN 1987A. A possible way of extending the constraint is also briefly discussed.