4,845 research outputs found
Cooper pairing with finite angular momentum: BCS versus Bose limits
We revisit the old problem of exotic superconductivity as Cooper pairing with finite angular momentum emerging from a central potential.
Based on some general considerations, we suggest that the phenomenon
is associated with interactions that keep electrons at some particular,
finite distance r(0), and occurs at a range of intermediate densities
n similar to 1/r(0)(3). We discuss the ground state and the critical
temperature in the framework of a standard functional-integral theory
of the BCS to Bose crossover. We find that, due to the lower energy
of two-body bound states with l = 0, the rotational symmetry of the
ground state is always restored on approaching the Bose limit. Moreover
in that limit the critical temperature is always higher for pairs
with l = 0. The breaking of the rotational symmetry of the continuum
by the superfluid state thus seems to be a property of weakly-attractive,
non-monotonic interaction potentials, at intermediate densities
Analysis of the BATSE Continuous MER data
The CGRO/BATSE database includes many types of data such as the 16-channel
continuous background or medium energy resolution burst data (CONT and MER data
types). We have calculated some four hundred burst's medium energy resolution
spectra and Principal Component Analysis has been applied. We found five
components can describe GRBs' spectra.Comment: 4 pages, 2 figures, accepted in Nuovo Ciment
Survival analysis of the optical brightness of GRB host galaxies
We studied the unbiased optical brightness distribution which was calculated
from the survival analysis of host galaxies and its relationship with the Swift
GRB data of the host galaxies observed by the Keck telescopes. Based on the
sample obtained from merging the Swift GRB table and the Keck optical data we
also studied the dependence of this distribution on the data of the GRBs.
Finally, we compared the HGs distribution with standard galaxies distribution
which is in the DEEP2 galaxies catalog.Comment: Swift: 10 Years of Discovery. Conference paper. 2-5 December 2014. La
Sapienza University, Rome, Ital
Intrinsic optical dichroism in the chiral superconducting state of SrRuO
We present an analysis of the Hall conductivity in
time reversal symmetry breaking states of exotic superconductors. We find that
the dichroic signal is non-zero in systems with inter-band order parameters.
This new intrinsic mechanism may explain the Kerr effect observed in strontium
ruthenate and possibly other superconductors. We predict coherence factor
effects in the temperature dependence of the imaginary part of the ac Hall
conductivity , which can be tested experimentally.Comment: 4+ pages, 4 figures, published versio
Comparing the observed properties of the GRBs detected by the Fermi and Swift satellites
We studied the distribution of the GRBs, observed by the Fermi satellite, in
the multidimensional parameter space consisting of the duration, Fluence, Peak
flux and Peak energy (if it was available). About 10% of the Fermi bursts was
observed also by the Swift satellite. We did not find significant differences
between the Peak flux and Peak energy of GRBs observed and not observed also by
the Swift satellite. In contrast, those GRBs detected also by the Swift
satellite had significantly greater Fluence and duration. We did a similar
study for the GRBs detected by the Swift satellite. About 30% percent of these
bursts was also measured by the Fermi satellite. We found a significant
difference in the Fluence, Peak flux and Photon index but none in duration.
These differences may be accounted for the different construction and observing
strategy of the Fermi and Swift satellites.Comment: 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013: paper 5 in eConf
Proceedings C130414
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