8 research outputs found
Vortex in a d-wave superconductor at low temperatures
A systematic perturbation theory is developed to describe the magnetic
field-induced subdominant - and -wave order parameters in the mixed
state of a -wave superconductor, enabling us to obtain, within
weak-coupling BCS theory, analytic results for the free energy of a d-wave
superconductor in an applied magnetic field H_{c1}\ltsim H\ll H_{c2} from
down to very low temperatures. Known results for a single isolated vortex
in the Ginzburg-Landau regime are recovered, and the behavior at low
temperatures for the subdominant component is shown to be qualitatively
different. In the case of subdominant pair component, superfluid
velocity gradients and an orbital Zeeman effect are shown to compete in
determining the vortex state, but for realistic field strengths the latter
appears to be irrelevant. On this basis, we argue that recent predictions of a
low-temperature phase transition in connection with recent thermal conductivity
measurements are unlikely to be correct.Comment: 20 RevTEX pages, 6 EPS figures; considerably expanded versio
Field induced state and marginal stability of high-Tc superconductors
It is shown that the {\em complex} component is generated in d-wave
superconductor in the magnetic field. As one enters superconducting state at
finite field the normal to superconducting transition occurs into bulk
state . The driving force for the transition is the
linear coupling between magnetic field and non zero magnetization of the
condensate. The external magnetic field violates parity
and time reversal symmetries and the nodal quasiparticle states respond by
generating the component of the order parameter, with the magnitude
estimated to be on the order of few Kelvin. Parity (P) and time reversal (T)
symmetries are violated in this state.Comment: 4 pages, latex file with two eps figure file
The challenge and response to global tourism in the post-modern era: the commodification, reconfiguration and mutual transformation of Habana Vieja, Cuba
There is a growing literature on the symbolic and cultural meanings of tourism and the ways in which cities are increasingly competing for tourists through the promotion of cultural assets and different forms of spectacle in the `tourist bubble'. To date, research on the role and impact of tourism in cities has largely been confined to those in Western, post-industrial economies. This paper examines the growth of cultural tourism in the central area of Havana, Cuba, and explores the range of unique, devolved, state-owned enterprises that are attempting to use tourism as a funding mechanism to achieve improvements in the social and cultural fabric of the city for the benefit of residents. The paper concludes with an assessment of the implications of this example for our understanding of how the pressures for restructuring and commodification can be moderated at the city level. Copyright 2008 SAGE Publications. All rights reserved. Not for commercial use or unauthorized distribution
The effect of smear layer removal on marginal contraction gaps.
Journal of Oral Rehabilitation214411-41