1,303 research outputs found
Specific heat across the superconducting dome in the cuprates
The specific heat of the superconducting cuprates is calculated over the
entire phase diagram. A d-wave BCS approach based on the large Fermi surface of
Fermi liquid and band structure theory provides a good description of the
overdoped region. At underdoping it is essential to include the emergence of a
second energy scale, the pseudogap and its associated Gutzwiller factor, which
accounts for a reduction in the coherent piece of the electronic Green's
function due to increased correlations as the Mott insulating state is
approached. In agreement with experiment, we find that the slope of the linear
in T dependence of the low temperature specific heat rapidly increases above
optimum doping while it is nearly constant below optimum. Our theoretical
calculations also agree with recent data on BiSrLaCuO for which the normal state is accessed through the
application of a large magnetic field. A quantum critical point is located at a
doping slightly below optimum.Comment: submitted to PRB; 8 pages, 5 figure
Grobner Bases for Finite-temperature Quantum Computing and their Complexity
Following the recent approach of using order domains to construct Grobner
bases from general projective varieties, we examine the parity and
time-reversal arguments relating de Witt and Lyman's assertion that all path
weights associated with homotopy in dimensions d <= 2 form a faithful
representation of the fundamental group of a quantum system. We then show how
the most general polynomial ring obtained for a fermionic quantum system does
not, in fact, admit a faithful representation, and so give a general
prescription for calcluating Grobner bases for finite temperature many-body
quantum system and show that their complexity class is BQP
Detection and Mapping of Decoupled Stellar and Ionized Gas Structures in the Ultraluminous Infrared Galaxy IRAS 12112+0305
Integral field optical spectroscopy with the INTEGRAL fiber-fed system and
HST optical imaging are used to map the complex stellar and warm ionized gas
structure in the ultraluminous infrared galaxy IRAS 12112+0305. Images
reconstructed from wavelength-delimited extractions of the integral field
spectra reveal that the observed ionized gas distribution is decoupled from the
stellar main body of the galaxy, with the dominant continuum and emission-line
regions separated by projected distances of up to 7.5 kpc. The two optical
nuclei are detected as apparently faint emission-line regions, and their
optical properties are consistent with being dust-enshrouded weak-[OI] LINERs.
The brightest emission-line region is associated with a faint (m_{I}= 20.4),
giant HII region of 600 pc diameter, where a young (about 5 Myr) massive
cluster of about 2 10 dominates the ionization.
Internal reddening towards the line-emitting regions and the optical nuclei
ranges from 1 to 8 magnitudes, in the visual. Taken the reddening into aacount,
the overall star formation in IRAS 12112+0305 is dominated by starbursts
associated with the two nuclei and corresponding to a star formation rate of 80
yr.Comment: 2 figures, accepted to Ap.J. Letter
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