2,230 research outputs found
Selforganized 3-band structure of the doped fermionic Ising spin glass
The fermionic Ising spin glass is analyzed for arbitrary filling and for all
temperatures. A selforganized 3-band structure of the model is obtained in the
magnetically ordered phase. Deviation from half filling generates a central
nonmagnetic band, which becomes sharply separated at T=0 by (pseudo)gaps from
upper and lower magnetic bands. Replica symmetry breaking effects are derived
for several observables and correlations. They determine the shape of the
3-band DoS, and, for given chemical potential, influence the fermion filling
strongly in the low temperature regime.Comment: 13 page
Are nurses the key to the increased uptake of frequent nocturnal home haemodialysis in Australia?
Background: Although there are significant benefits to frequent nocturnal home haemodialysis (NHHD) there has been a low acceptance of this therapy in Australia. Aim: The aim of this paper is to explore and discuss the literature relating to the nursing barriers to frequent nocturnal home haemodialysis. Methods: A search of nursing, medical, social work and psychological literature was performed. Results: Nurses are key contributors to the increase of NHHD within the dialysis population. Knowledge, culture and nurse satisfaction are key areas to address to increase NHHD uptake. Conclusion: Nurses need to challenge the cultural and organisational barriers that are preventing further uptake of NHHD. If nurses do not we cannot claim to be helping patients attain their best possible outcome.<br /
Harmonic crossover exponents in O(n) models with the pseudo-epsilon expansion approach
We determine the crossover exponents associated with the traceless tensorial
quadratic field, the third- and fourth-harmonic operators for O(n) vector
models by re-analyzing the existing six-loop fixed dimension series with
pseudo-epsilon expansion. Within this approach we obtain the most accurate
theoretical estimates that are in optimum agreement with other theoretical and
experimental results.Comment: 12 pages, 1 figure. Final version accepted for publicatio
Faraday Rotation as a diagnostic of Galactic foreground contamination of CMB maps
The contribution from the residuals of the foreground can have a significant
impact on the temperature maps of the Cosmic Microwave Background (CMB).
Mostly, the focus has been on the galactic plane, when foreground cleaning has
taken place. However, in this paper, we will investigate the possible
foreground contamination, from sources outside the galactic plane in the CMB
maps. We will analyze the correlation between the Faraday rotation map and the
CMB temperature map. The Faraday rotation map is dependent on the galactic
magnetic field, as well as the thermal electron density, and both may
contribute to the CMB temperature. We find that the standard deviation for the
mean cross correlation deviate from that of simulations at the 99.9% level.
Additionally, a comparison between the CMB temperature extrema and the extremum
points of the Faraday rotation is also performed, showing a general overlap
between the two. Also we find that the CMB Cold Spot is located at an area of
strong negative cross correlation, meaning that it may be explained by a
galactic origin. Further, we investigate nearby supernova remnants in the
galaxy, traced by the galactic radio loops. These super nova remnants are
located at high and low galactic latitude, and thus well outside the galactic
plane. We find some correlation between the Faraday Rotation and the CMB
temperature, at select radio loops. This indicate, that the galactic
foregrounds may affect the CMB, at high galactic latitudesComment: 13 pages, 22 figures, 6 table
Spin - glass transition in Kondo lattice with quenched disorder
We use the Popov-Fedotov representation of spin operators to construct an
effective action for a Kondo lattice model with quenched disorder at finite
temperatures. We study the competition between the Kondo effect and frozen spin
order in Ising-like spin glass. We present the derivation of new mean-field
equations for the spin-glass order parameter and analyze the effects of
screening of localized spins by conduction electrons on the spin-glass phase
transition.Comment: 6 pages, jetpl style included, to appear in JETP Letter
Tricritical behaviour of Ising spin glasses with charge fluctuations
We show that tricritical points displaying unusal behaviour exist in phase
diagrams of fermionic Ising spin glasses as the chemical potential or the
filling assumes characteristic values. Exact results for infinite range
interaction and a one loop renormalization group analysis of thermal
tricritical fluctuations for finite range models are presented. Surprising
similarities with zero temperature transitions and a new tricritical
point of metallic quantum spin glasses are derived.Comment: 4 pages, 1 Postscript figure, minor change
Huddle test measurement of a near Johnson noise limited geophone
In this paper, the sensor noise of two geophone configurations (L-22D and L-4C geophones from Sercel with custom built amplifiers) was measured by performing two huddle tests. It is shown that the accuracy of the results can be significantly improved by performing the huddle test in a seismically quiet environment and by using a large number of reference sensors to remove the seismic foreground signal from the data. Using these two techniques, the measured sensor noise of the two geophone configurations matched the calculated predictions remarkably well in the bandwidth of interest (0.01 Hz–100 Hz). Low noise operational amplifiers OPA188 were utilized to amplify the L-4C geophone to give a sensor that was characterized to be near Johnson noise limited in the bandwidth of interest with a noise value of 10−11 m/Hz⎯⎯⎯⎯⎯√10−11 m/Hz at 1 Hz
Critical disorder effects in Josephson-coupled quasi-one-dimensional superconductors
Effects of non-magnetic randomness on the critical temperature T_c and
diamagnetism are studied in a class of quasi-one dimensional superconductors.
The energy of Josephson-coupling between wires is considered to be random,
which is typical for dirty organic superconductors. We show that this
randomness destroys phase coherence between the wires and T_c vanishes
discontinuously when the randomness reaches a critical value. The parallel and
transverse components of the penetration depth are found to diverge at
different critical temperatures T_c^{(1)} and T_c, which correspond to
pair-breaking and phase-coherence breaking. The interplay between disorder and
quantum phase fluctuations results in quantum critical behavior at T=0,
manifesting itself as a superconducting-normal metal phase transition of
first-order at a critical disorder strength.Comment: 4 pages, 2 figure
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