12,655 research outputs found

    Ідентичність людини в сучасних умовах: роздуми над ціннісними пріоритетами екзистенціальної теології Дж. Маккуорі. (Identity of man in modern terms: reflections on the value priorities of existential theology of J. MacQuarrie.)

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    У статті розкривається проблема інтерпретації Дж. Маккуоррі ціннісних підвалин християнства відповідно до вимог сучасної реальності. Аналізується питання подолання кризи релігійної ідентичності людини, якому присвячена праця філософа “Принципи християнської теології”. Досліджується специфіка синтезу екзистенціалізму та теології. (The article deals with the problem of interpretation J. MacQuarrie value foundations of Christianity, according to today’s reality. Examines the question of overcoming the crisis of religious identity of the person is devoted to the philosopher, “Principles of Christian Theology”. We investigate the specificity of the synthesis of existentialism and theology.

    UBVR observation of V1357 Cyg = Cyg X-1. Search of the optical radiation of the accretion disk

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    Data from 30 nights of V 1357 Cyg observations in July, August, and September of 1977 are presented. The contribution of the disk to the optic brightness of the system is computed with regard for the heating of its surface by ultraviolet radiation from V 1357 Cyg and X-ray radiation from Cyg X-1. The disk radiation explains the irregular variability in the system brightness. The possibility of the eclipse of the star by the disk and the disk by the star is discussed

    Relaxation of superflow in a network: an application to the dislocation model of supersolidity of helium crystals

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    We have considered the dislocation network model for the supersolid state in He-4 crystals. In difference with uniform 2D and 3D systems, the temperature of superfluid transition T_c in the network is much smaller than the degeneracy temperature T_d. It is shown that a crossover into a quasi superfluid state occurs in the temperature interval between T_c and T_d. Below the crossover temperature the time of decay of the flow increases exponentially under decrease of the temperature. The crossover has a continuous character and the crossover temperature does not depend on the density of dislocations.Comment: Corrected typo

    On the dipole moment of quantized vortices generated by flows

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    The polarization charge ρ\rho of an inhomogeneous superfluid system is expressed as a function of the order parameter Φ(r1,r2)\Phi ({{\mathbf{r}}_{1}},{{\mathbf{r}}_{2}}). It is shown that if the order parameter changes on macroscopic distances, the polarization charge ρpol{{\rho }_{pol}} is proportional to A2nA{{\nabla }^{2}}n, and the polarization P\mathbf{P} is proportional to AnA\nabla n, where nn is the density of the system. For noninteracting atoms the proportionality coefficient AA is independent of density, and in the presence of interaction AA is proportional to nn. The change of the Bose gas density is found in the presence of a flow w=vnvs\mathbf{w}={{\mathbf{v}}_{n}}-{{\mathbf{v}}_{s}} passing the vortex. It is found that a vortex in a superfluid film creates an electric potential above the film. This potential has the form of a potential of a dipole, allowing to assign a dipole moment to the vortex. The dipole moment is a sum of two terms, the first one is proportional to the relative flow velocity w\mathbf{w} and the second one is proportional to [κ×w]\left[ \mathbf{\kappa }\times \mathbf{w} \right], where κ\mathbf{\kappa } is the vortex circulation.Comment: 6 page

    Vortex generation in a superfluid gas of dipolar chains in crossed electric and magnetic fields

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    Crossed electric and magnetic fields influence dipolar neutral particles in the same way as the magnetic field influences charged particles. The effect of crossed fields is proportional to the dipole moment of the particle (inherent or induced). We show that this effect is quite spectacular in a multilayer system of polar molecules. In this system molecules may bind in chains. At low temperature the gas of chains becomes the superfluid one. The crossed fields then induce vortices in the superfluid gas of chains. The density of vortices is proportional to the number of particles in the chain. The effect can be used for monitoring the formation and destruction of chains in multilayer dipolar gases.Comment: To appear in Low Temperature Physics/Fizika Nizkikh Temperatur, 2020, v. 46, No.

    Impact of the transport supercurrent on the Josephson effect

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    We study the weak link between current-carrying superconductors, both conventional and d-wave. The state of the system is controlled by two parameters: the order parameter phase difference ϕ\phi and the superfluid velocity vsv_{s}, which parameterizes the parallel to the boundary transport supercurrent which is injected externally. The low-temperature current-phase relations are derived. We consider two models of weak links: a constriction between two conventional superconductors and a plane boundary between two differently orientated d-wave superconductors. We show that for some relation between ϕ\phi and vsv_{s} quasiparticles create the current along the boundary which flows in the direction opposite to the transport supercurrent.Comment: 5 pages, 3 figures; submitted for publication in Proceedings of MS+S2004 symposium (without Sec.V and the last part of Sec.III

    Vortex matter and generalizations of dipolar superfluidity concept in layered systems

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    In the first part of this letter we discuss electrodynamics of an excitonic condensate in a bilayer. We show that under certain conditions the system has a dominant energy scale and is described by the effective electrodynamics with "planar magnetic charges". In the second part of the paper we point out that a vortex liquid state in bilayer superconductors also possesses dipolar superfluid modes and establish equivalence mapping between this state and a dipolar excitonic condensate. We point out that a vortex liquid state in an N-layer superconductor possesses multiple topologically coupled dipolar superfluid modes and therefore represents a generalization of the dipolar superfluidity concept.Comment: v2: references added. v3: discussion extended, references adde
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