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41.
42.
Yuri V. Kozitsky 《Journal of statistical physics》1997,87(3-4):799-820
The hierarchical ferromagneticN-dimensional vector spin model as a sequence of probability measures onR
N
is considered. The starting element of this sequence is chosen to belong to the Lee-Yang class of measures that is defined in the paper and includes most known examples (4 measures, Gaussian measures, and so on). For this model, we probe two thermodynamic limit theorems. One of them is just the classical central limit theorem for weakly dependent random vectors. It describes the convergence of classically normed sums of spins when temperature is sufficiently high. The other theorem describes the convergence of more than normally normed sums that holds for some fixed temperature. It corresponds to the strong dependence of spins, which appears at the critical point of the model. 相似文献
43.
Letters in Mathematical Physics - 相似文献
44.
Optical properties of polarization-dependent geometric phase elements with partially polarized light
Yuri Gorodetski 《Optics Communications》2006,266(2):365-375
The behavior of geometric phase elements illuminated with partially polarized monochromatic beams is investigated both theoretically and experimentally. The element discussed in this paper is composed of wave plates with π-retardation and a space-variant orientation angle. We found that a beam emerging from such an element comprises two polarization orders; right-and left-handed circularly polarized states with conjugate geometric phase modification. This phase equals twice the orientation angle of the space-variant wave plate comprising the element. Apart from the two polarization orders, the emerging beam coherence polarization matrix includes a “vectorial interference matrix” which contains information concerning the correlation between the two orthogonal, circularly polarized portions of the incident beam. In this paper we measure this correlation by a simple interference experiment. In addition, we found that the equivalent mutual intensity of the emerging beam is modulated according to the geometric phase induced by the element. Other interesting phenomena concerning propagation will be discussed theoretically and demonstrated experimentally. The experiment made use of a spherical geometric phase element that was realized by use of a space-variant subwavelength grating illuminated with CO2 laser radiation of 10.6 μm wavelength. 相似文献
45.
We study discrete vector solitons and vortices in two-dimensional photonic lattices with Kerr nonlinearity and demonstrate novel types of stable, incoherently coupled dipoles and vortex-soliton complexes that can be excited by Gaussian beams. We also discuss what we believe to be novel scenarios of the charge-flipping instability of incoherently coupled discrete vortices. 相似文献
46.
Yuri P. Kalmykov William T. Coffey Serguey V. Titov 《Journal of statistical physics》2008,131(5):969-987
A master equation, for the time evolution of the quasi-probability density function of spin orientations in the phase space
representation of the polar and azimuthal angles is derived for a uniaxial spin system subject to a magnetic field parallel
to the axis of symmetry. This equation is obtained from the reduced density matrix evolution equation (assuming that the spin-bath
coupling is weak and that the correlation time of the bath is so short that the stochastic process resulting from it is Markovian)
by expressing it in terms of the inverse Wigner-Stratonovich transformation and evaluating the various commutators via the
properties of polarization operators and spherical harmonics. The properties of this phase space master equation, resembling
the Fokker-Planck equation, are investigated, leading to a finite series (in terms of the spherical harmonics) for its stationary
solution, which is the equilibrium quasi-probability density function of spin “orientations” corresponding to the canonical
density matrix and which may be expressed in closed form for a given spin number. Moreover, in the large spin limit, the master
equation transforms to the classical Fokker-Planck equation describing the magnetization dynamics of a uniaxial paramagnet. 相似文献
47.
Minovich A Klein AE Janunts N Pertsch T Neshev DN Kivshar YS 《Physical review letters》2011,107(11):116802
We demonstrate experimentally the generation and near-field imaging of nondiffracting surface waves, plasmonic Airy beams, propagating on the surface of a gold metal film. The Airy plasmons are excited by an engineered nanoscale phase grating, and demonstrate significant beam bending over their propagation. We show that the observed Airy plasmons exhibit self-healing properties, suggesting novel applications in plasmonic circuitry and surface optical manipulation. 相似文献
48.
Concentration dependence of nonlinear refractive index n2 in fibers heavily doped with GeO2 is studied by using the D-scan method. Good agreement with an empirical dependence established earlier with lower GeO2 concentrations by the cw dual-frequency beat signal technique is shown for GeO2 concentrations up to approximately 100 mol.%. The highest values of the nonlinear coefficient gamma at 1.25 microm of 47.9, 57.7, and 70.9 W(-1) km(-1) were obtained in fibers doped with 67, 75, and 97 mol.% GeO2, respectively. 相似文献
49.
We study, both theoretically and experimentally, the Bragg scattering of light in optically induced photonic lattices and reveal the key physical mechanisms which govern the nonlinear self-action of narrow beams under the combined effects of Bragg scattering and wave diffraction, allowing for selecting bands with different effective dispersion. 相似文献
50.
We consider a discretized volume V consisting of finite, congruent and attached copies of a tile t. We find a group L
V
the orbit of which, when applied to t, is just V. We show the connection between the structural matrixQ in the formal solution of a boundary value problem formulated for volume V and the so called auxiliary matrix of the graph Γ
v
associated with V. We show boundary value problems to be isomorphic if the graphs associated with the volumes are isomorphic, or, if the covering
groups are Sunada pairs. 相似文献