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Vortex lattice (VL) elastic response is analyzed within the nonlocal London model which holds for high-kappa clean superconductors. The squash modulus vanishes at the field H( square) where VL undergoes a square-to-rhombus transition. For H>H( square), where the square VL is stable, the rotation modulus turns zero at H = H(r), indicating VL instability to rotations. The shear modulus depends on the shear direction; the dependence is strong in the vicinity of H( square) where the square VL is soft with respect to the shear along [110]. The H dependences of the moduli are evaluated for LuNi(2)B(2)C. 相似文献
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A simple-yet plausible-model for B-type vortex breakdown flows is postulated; one that is based on the immersion of a pair of slender coaxial vortex rings in a swirling flow of an ideal fluid rotating around the axis of symmetry of the rings. It is shown that this model exhibits in the advection of passive fluid particles (kinematics) just about all of the characteristics that have been observed in what is now a substantial body of published research on the phenomenon of vortex breakdown. Moreover, it is demonstrated how the very nature of the fluid dynamics in axisymmetric breakdown flows can be predicted and controlled by the choice of the initial ring configurations and their vortex strengths. The dynamic intricacies produced by the two ring + swirl model are illustrated with several numerical experiments. 相似文献
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A model of “planar” baryons with (10 + 8) ? (1 + 8) exchange degeneracy is proposed, based on duality and unitarity. Dynamical mechanisms for deviation from the “planar” baryons are considered and the consequent pattern of broken exchange degenerate trajectories is compared with observed baryon spectra. Our model suggests a string picture of linear molecule type for baryons. 相似文献
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Peter K. Anastasovski T. E. Bearden C. Ciubotariu W. T. Coffey L. B. Crowell G. J. Evans M. W. Evans R. Flower S. Jeffers A. Labounsky D. Leporini B. Lehnert M. Mészáros J. K. Moscicki P. R. Molnár H. Múnera E. Recami D. Roscoe S. Roy 《Foundations of Physics Letters》1999,12(3):251-265
The general theory of gauge fields is used to develop a theory of electrodynamics in which the fundamental structure is non-Abelian and in which the internal gauge field symmetry is O(3), based on the existence of circular polarization and the third Stokes parameter. The theory is used to provide an explanation for the Sagnac effect with platform at rest and in motion. The Sagnac formula is obtained by considering the platform in motion to be a gauge transformation. The topological phases can be described straightforwardly with non Abelian electrodynamics, which produces a novel magnetic field component for all types of radiation, a component which is proportional to the third Stokes parameter. The theory provides a natural explanation for the inverse Faraday effect without phenomenology. 相似文献
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Alexandre Joel Chorin 《Journal of statistical physics》1992,69(1-2):67-78
Simple lattice vortex models are presented that exhibit vortex percolation along lines in a temperature/chemical potential plane. Parts of these lines can be identified with the percolation threshold at the inertial range of turbulence, and other parts are analogous to the transition in a three-dimensionalXY model that may model the . transition in superfluidity. Flory exponents at percolation are calculated; for nonnegative temperatures, their values approximate the standard Flory value, and are approximately constant along the transition lines, in agreement with recent conjectures. Conclusions regarding coherent structures in turbulence are also reached. 相似文献
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E. V. Bugaev O. N. Gaponenko 《The European Physical Journal C - Particles and Fields》1998,5(1):103-110
The question of the energy behavior of the partial inelasticities is studied in the context of the dual parton model. A simple
analytical expression is derived which describes the behavior of the partial inelasticities at high energies. A comparison
with the results of some other models is also given. The question of the violation of Feynman scaling is considered with reference
to the inelasticity problem.
Received: 8 August 1997 / Revised version: 12 December 1997 / Published online: 10 March 1998 相似文献
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A model in statistical physics is presented based on assigning non-Abelian phase factors to the turning points of polygons in three dimensions. This model allows for an exact solution and exhibits an unexpectedly rich phase structure. The model as well as the solution are obtained by a generalization of the methods of Kac and Ward and by mapping the problem to a Markov process as was done by Feynman for the two-dimensional Ising model 相似文献
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《Nuclear Physics B》1995,454(3):541-560
We propose a new formulation of the space-time interpretation of the c = 1 matrix model. Our formulation uses the well-known leg-pole factor that relates the matrix model amplitudes to that of the 2-dimensional string theory, but includes fluctuations around the Fermi vacuum on both sides of the inverted harmonic oscillator potential of the double-scaled model, even when the fluctuations are small and confined entirely within the asymptotes in the phase plane. We argue that including fluctuations on both sides of the potential is essential for a consistent interpretation of the leg-pole transformed theory as a theory of space-time gravity. We reproduce the known results for the string theory tree-level scattering amplitudes for flat space and linear dilaton background as a special case. We show that the generic case corresponds to more general space-time backgrounds. In particular, we identify the parameter corresponding to background metric perturbation in string theory (black-hole mass) in terms of the matrix model variables. Possible implications of our work for a consistent non-perturbative definition of string theory as well as for quantized gravity and black-hole physics are discussed. 相似文献
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There exist several ways of constructing general relativity from ‘first principles’: Einstein’s original derivation, Lovelock’s results concerning the exceptional nature of the Einstein tensor from a mathematical perspective, and Hojman–Kucha?-Teitelboim’s derivation of the Hamiltonian form of the theory from the symmetries of space–time, to name a few. Here I propose a different set of first principles to obtain general relativity in the canonical Hamiltonian framework without presupposing space–time in any way. I first require consistent propagation of scalar spatially covariant constraints (in the Dirac picture of constrained systems). I find that up to a certain order in derivatives (four spatial and two temporal), there are large families of such consistently propagated constraints. Then I look for pairs of such constraints that can gauge-fix each other and form a theory with two dynamical degrees of freedom per space point. This demand singles out the ADM Hamiltonian either in (i) CMC gauge, with arbitrary (finite, non-zero) speed of light, and an extra term linear in York time, or (ii) a gauge where the Hubble parameter is conformally harmonic. 相似文献
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We consider the type-IIB background generated by the strong-coupling limit of Nc D5 branes wrapped on S2, and focus our attention on a special class of solutions that exhibit walking behavior. We compute numerically the spectrum of scalar fluctuations around vacua of this class. Besides two cuts, and sequences of single poles converging on one of the branch points, the spectrum contains one isolated scalar, the mass of which is suppressed by the length of the walking region. Approximate scale-invariance symmetry in the walking region suggests that this might be interpreted as a light dilaton, the pseudo-Goldstone boson of dilatations. 相似文献
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D. Förster 《Nuclear Physics B》1974,81(1):84-92
We analyse the dynamics of relativistic vortex lines that occur in some classical field theories. We prove that in the zero-width limit they move like Nambu strings. We also discuss the relevance of vortex lines to the corresponding quantum field theory. 相似文献
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Satoru Saito 《Nuclear Physics B》1975,94(2):344-364
A dual resonance model is formulated as a Brownian motion of strings on a flow of some material. It obeys the Mayer-Montroll equation of classical statistical mechanics which enables us to make a fugacity expansion. Certain divergences in the conventional loop expansion are absent in each term of the fugacity expansion, thus showing that the Kikkawa-Sakita-Virasoro dual amplitude is, by itself, free from these divergences, if all the diagrams are added and rearranged properly. In particular the first order term of the fugacity expansion reproduces the renormalized Neveu-Scherk one-loop amplitude, when the dimension of space-time is twelve. 相似文献
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We construct rigorously an infinite dimensional distribution which corresponds to the Chern-Simons (CS) functional
integral associated with a principal fiber bundle over R
3 with structure group a compact connected Lie group. We determine the ‘moments’ of the CS distribution and show that these
coincide with those used in informal studies of the CS integral. A locality property of the CS distribution is proven. The
complexified theory of Fr?hlich and King is also discussed within our framework.
Received: 2 April 1996 / Accepted: 15 August 1996 相似文献
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We study the cosmological meaning of duality symmetry by considering a two dimensional model of string cosmology. We find that as seen by an internal observer in this universe, the scale factor rebounds at the self-dual length. This rebound is a consequence of the adiabatic expansion. Furthermore, in this situation there are four mathematically different scenarios which describe physically equivalent universes which are in fact undistinguishable. We also stress that R-duality suffices to prove that all the possible evolutions present a maximum temperature. 相似文献
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David Tong 《Annals of Physics》2009,324(1):30-52
The quantum worldsheet dynamics of vortex strings contains information about the 4d non-Abelian gauge theory in which the string lives. Here I tell this story. The string worldsheet theory is typically some variant of the CPN-1 sigma-model, describing the orientation of the string in a U(N) gauge group. Qualitative parallels between 2d sigma-models and 4d non-Abelian gauge theories have been known since the 1970s. The vortex string provides a quantitative link between the two. In 4d theories with N=2 supersymmetry, the exact BPS spectrum of the worldsheet coincides with the bulk spectrum in 4d. Moreover, by tuning parameters, the CPN-1 sigma-model can be coaxed to flow to an interacting conformal fixed point which is related to the 4d Argyres-Douglas fixed point. For theories with N=1 supersymmetry, the worldsheet theory suffers dynamical supersymmetry breaking and, more interestingly, supersymmetry restoration, in a way which captures the physics of Seiberg’s quantum deformed moduli space. 相似文献
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Lattice motivated triplet color scalar field theory is analyzed. We consider non-minimal as well as covariant derivative coupling with SU(2) gauge fields. Field configurations generated by external electric sources are presented. Moreover non-Abelian magnetic monopoles are found. Dependence on the spatial coordinates in the obtained solutions is identical as in the usual Abelian case. We show also that after a decomposition of the fields a modified Faddeev-Niemi action can be obtained. It contains explicit O(3) symmetry breaking term parameterized by the condensate of an isoscalar field. Due to that Goldstone bosons observed in the original Faddeev-Niemi model are removed.Received: 23 January 2004, Revised: 29 July 2004, Published online: 11 January 2005 相似文献