2,398 research outputs found
Coulomb drag at \nu = 1/2: Composite fermion pairing fluctuations
We consider the Coulomb drag between two two-dimensional electron layers at
filling factor \nu = 1/2 each, using a strong coupling approach within the
composite fermion picture. Due to an attractive interlayer interaction,
composite fermions are expected to form a paired state below a critical
temperature T_c. We find that above T_c pairing fluctuations make the
longitudinal transresistivity \rho_D increase with decreasing temperature. The
pairing mechanism we study is very sensitive to density variations in the two
layers, and to an applied current. We discuss possible relation to an
experiment by Lilly et al. [Phys. Rev. Lett. 80, 1714 (1998)].Comment: REVTeX, 4 pages, 1 figur
Signatures of spin-charge separation in scanning probe microscopy
We analyze the effect of an auxiliary scatterer, such as the potential of a
scanning tip, on the conductance of an interacting one-dimensional electron
system. We find that the differential conductance for tunneling into the end of
a semi-infinite quantum wire reflects the separation of the elementary
excitations into spin and charge modes. The separation is revealed as a
specific pattern in the dependence of the conductance on bias and on the
position of the scatterer.Comment: 4 pages, 1 figure; published versio
Conductivity of thermally fluctuating superconductors in two dimensions
We review recent work on a continuum, classical theory of thermal
fluctuations in two dimensional superconductors. A functional integral over a
Ginzburg-Landau free energy describes the amplitude and phase fluctuations
responsible for the crossover from Gaussian fluctuations of the superconducting
order at high temperatures, to the vortex physics of the Kosterlitz-Thouless
transition at lower temperatures. Results on the structure of this crossover
are presented, including new results for corrections to the Aslamazov-Larkin
fluctuation conductivity.Comment: 9 page
Inside-Outside Duality for Planar Billiards -- A Numerical Study
This paper reports the results of extensive numerical studies related to
spectral properties of the Laplacian and the scattering matrix for planar
domains (called billiards). There is a close connection between eigenvalues of
the billiard Laplacian and the scattering phases, basically that every energy
at which a scattering phase is corresponds to an eigenenergy of the
Laplacian. Interesting phenomena appear when the shape of the domain does not
allow an extension of the eigenfunction to the exterior. In this paper these
phenomena are studied and illustrated from several points of view.Comment: uuencoded tar-compressed (using uufiles) postscript file, 15 page
New radiocarbon-based assessment supports the prominence of Tell Lachish during the Later Bronze Age IB-IIA
This article presents a new suite of radiocarbon (14C) dates for the lower portion of the Late Bronze Age (LBA) sequence of Area S, Tel Lachish. The results show that the lowest levels reached by Ussishkin in the 1980s (S-2 and S-3) date significantly earlier than was previously thought. Level S-3, with its monumental architecture, belongs in the 2nd half of the 15th century BCE, as does the commencement of Level S-2. The laminated deposit of S-2 continues through the first half of the 14th century BCE, coinciding at least in part with the Amarna period. This redating leads to improved agreement between archaeological and textual evidence regarding the presence of a substantial, prominent settlement at Lachish during LB IB-IIA, from the reign of Thutmoses III through the Amarna period.ISSN:0033-822
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