75,171 research outputs found
Coexistence of Antiferromagnetism and Triplet Superconductivity
The authors discuss the possibility of coexistence of antiferromagnetism and
triplet superconductivity as a particular example of a broad class of systems
where the interplay of magnetism and superconductivity is important. This paper
focuses on the case of quasi-one-dimensional metals, where it is known
experimentally that antiferromagnetism is in close proximity to triplet
superconductivity in the temperature versus pressure phase diagram. Over a
narrow range of pressures, the authors propose an intermediate non-uniform
phase consisting of alternating insulating antiferromagnetic and triplet
superonducting stripes.Comment: 9 pages, 3 figures. 2004 Conference of Magnetism and Magnetic
Material
Loop Quantum Cosmology in Bianchi Type I Models: Analytical Investigation
The comprehensive formulation for loop quantum cosmology in the spatially
flat, isotropic model was recently constructed. In this paper, the methods are
extended to the anisotropic Bianchi I cosmology. Both the precursor and the
improved strategies are applied and the expected results are established: (i)
the scalar field again serves as an internal clock and is treated as emergent
time; (ii) the total Hamiltonian constraint is derived by imposing the
fundamental discreteness and gives the evolution as a difference equation; and
(iii) the physical Hilbert space, Dirac observables and semi-classical states
are constructed rigorously. It is also shown that the state in the kinematical
Hilbert space associated with the classical singularity is decoupled in the
difference evolution equation, indicating that the big bounce may take place
when any of the area scales undergoes the vanishing behavior. The investigation
affirms the robustness of the framework used in the isotropic model by
enlarging its domain of validity and provides foundations to conduct the
detailed numerical analysis.Comment: 53 pages, 2 figures; more typos corrected; HyperTeX enable
Lateral imaging of the superconducting vortex lattice using Doppler-modulated scanning tunneling microscopy
By spatially mapping the Doppler effect of an in-plane magnetic field on the
quasiparticle tunneling spectrum, we have laterally imaged the vortex lattice
in superconducting 2H-NbSe2. Cryomagnetic scanning tunneling spectroscopy was
performed at 300 mK on the ab-surface oriented parallel to the field H.
Conductance images at zero bias show stripe patterns running along H, with the
stripe separation varying as H^-0.5. Regions of higher zero-bias conductance
show lower gap-edge conductance, consistent with spectral redistribution by
spatially-modulated superfluid momentum. Our results are interpreted in terms
of the interaction between vortical and screening currents, and demonstrate a
general method for probing subsurface vortices.Comment: 3 pages, 3 figures, to appear in Applied Physics Letter
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