1,428 research outputs found
Lifshitz-point critical behaviour to
We comment on a recent letter by L. C. de Albuquerque and M. M.
Leite (J. Phys. A: Math. Gen. 34 (2001) L327-L332), in which results to
second order in were presented for the critical
exponents , and
of d-dimensional systems at m-axial Lifshitz points.
We point out that their results are at variance with ours. The discrepancy is
due to their incorrect computation of momentum-space integrals. Their
speculation that the field-theoretic renormalization group approach, if
performed in position space, might give results different from when it is
performed in momentum space is refuted.Comment: Latex file, uses the included iop stylefiles; Uses the texdraw
package to generate included figure
Loschmidt Echo and Berry phase of the quantum system coupled to the XY spin chain: Proximity to quantum phase transition
We study the Loschmidt echo (LE) of a coupled system consisting of a central
spin and its surrounding environment described by a general XY spin-chain
model. The quantum dynamics of the LE is shown to be remarkably influenced by
the quantum criticality of the spin chain. In particular, the decaying behavior
of the LE is found to be controlled by the anisotropy parameter of the spin
chain. Furthermore, we show that due to the coupling to the spin chain, the
ground-state Berry phase for the central spin becomes nonanalytical and its
derivative with respect to the magnetic parameter in spin chain
diverges along the critical line , which suggests an alternative
measurement of the quantum criticality of the spin chain.Comment: 15 pages, 5 figure
Another proof of Gell-Mann and Low's theorem
The theorem by Gell-Mann and Low is a cornerstone in QFT and zero-temperature
many-body theory. The standard proof is based on Dyson's time-ordered expansion
of the propagator; a proof based on exact identities for the time-propagator is
here given.Comment: 5 page
First-order super-radiant phase transitions in a multi-qubit--cavity system
We predict the existence of novel first-order phase transitions in a general
class of multi-qubit-cavity systems. Apart from atomic systems, the associated
super-radiant phase transition should be observable in a variety of solid-state
experimental systems, including the technologically important case of
interacting quantum dots coupled to an optical cavity mode.Comment: To appear in Phys. Rev. Let
A Model for Integration and Interlinking of Idea Management Systems
This paper introduces the use of Semantic Web technologies for the Idea Management Systems as a gap closer between heterogeneous software and achieving interoperability. We present a model that proposes how and what kind of rich metadata annotations to apply in the domain of Idea Management Systems. In addition, as a part of our model, we present a Generic Idea and Innovation Management Ontology (GI2MO). The described model is backed by a set of use cases followed by evaluations that prove how Semantic Web can work as tool to create new opportunities and leverage the contemporary Idea Management legacy systems into the next level
From research to practice: Implementing an experimental home treatment model into routine mental health care
Background
In line with previous findings, in a recent randomized controlled trial (RCT), we found that home treatment (HT) for acute mental health care can reduce (substitute) hospital use among severely ill patients in crises. This study examined whether the findings of the RCT generalize to HT services provided under routine care conditions.
Methods
We compared patients who received HT during the RCT study phase with patients who received the same HT service after it had become part of routine mental health services in the same catchment area. Sociodemographic and clinical characteristics as well as service use (HT and hospital bed days) were compared between the RCT and the subsequent routine care study period.
Results
Compared to patients who received HT during the RCT, routine care HT patients were more often living with others, less often admitted compulsorily, more often diagnosed with anxiety and stress-related disorders (ICD-10 F4) and less often diagnosed with schizophrenia spectrum disorders (F2). When compared to patients who were exclusively treated on hospital wards, involvement of the HT team in patients’ care was associated with a clear-cut reduction of hospital bed days both during the RCT and under routine care conditions. However, unlike during the RCT study period, involvement of HT was associated with longer overall treatment episodes (inpatient + HT days) under routine care conditions.
Conclusions
HT seems to reduce the use of hospital bed days even under routine care conditions but is at risk of producing longer overall acute treatment episodes
Minority carrier device comprising a passivating layer including a Group 13 element and a chalcogenide component
A minority carrier device includes at least one junction of at least two dissimilar materials, at least one of which is a semiconductor, and a passivating layer on at least one surface of the device. The passivating layer includes a Group 13 element and a chalcogenide component. Embodiments of the minority carrier device include, for example, laser diodes, light emitting diodes, heterojunction bipolar transistors, and solar cells
A comparative study of the neutrino-nucleon cross section at ultra high energies
The high energy neutrino cross section is a crucial ingredient in the
calculation of the event rate in high energy neutrino telescopes. Currently
there are several approaches which predict different behaviours for its
magnitude for ultrahigh energies. In this paper we present a comparison between
the predictions based on linear DGLAP dynamics, non-linear QCD and in the
imposition of a Froissart-like behaviour at high energies. In particular, we
update the predictions based on the Color Glass Condensate, presenting for the
first time the results for using the solution of the running
coupling Balitsky-Kovchegov equation. Our results demonstrate that the current
theoretical uncertainty for the neutrino-nucleon cross section reaches a factor
three for neutrinos energies around GeV and increases to a factor
five for GeV.Comment: 6 pages, 3 figure
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