12,166 research outputs found
Thermal signatures of Little-Parks effect in the heat capacity of mesoscopic superconducting rings
We present the first measurements of thermal signatures of the Little-Parks
effect using a highly sensitive nanocalorimeter. Small variations of the heat
capacity of 2.5 millions of non interacting micrometer-sized
superconducting rings threaded by a magnetic flux have been measured by
attojoule calorimetry. This non-invasive method allows the measurement of
thermodynamic properties -- and hence the probing of the energy levels -- of
nanosystems without perturbing them electrically. It is observed that is
strongly influenced by the fluxoid quantization (Little-Parks effect) near the
critical temperature . The jump of at the superconducting phase
transition is an oscillating function of with a period ,
the magnetic flux quantum, which is in agreement with the Ginzburg-Landau
theory of superconductivity.Comment: To be published in Physical Review B, Rapid Communication
Stability of Horava-Lifshitz Black Holes in the Context of AdS/CFT
The anti--de Sitter/conformal field theory (AdS/CFT) correspondence is a
powerful tool that promises to provide new insights toward a full understanding
of field theories under extreme conditions, including but not limited to
quark-gluon plasma, Fermi liquid and superconductor. In many such applications,
one typically models the field theory with asymptotically AdS black holes.
These black holes are subjected to stringy effects that might render them
unstable. Ho\v{r}ava-Lifshitz gravity, in which space and time undergo
different transformations, has attracted attentions due to its power-counting
renormalizability. In terms of AdS/CFT correspondence, Ho\v{r}ava-Lifshitz
black holes might be useful to model holographic superconductors with Lifshitz
scaling symmetry. It is thus interesting to study the stringy stability of
Ho\v{r}ava-Lifshitz black holes in the context of AdS/CFT. We find that
uncharged topological black holes in Ho\v{r}ava-Lifshitz theory are
nonperturbatively stable, unlike their counterparts in Einstein gravity, with
the possible exceptions of negatively curved black holes with detailed balance
parameter close to unity. Sufficiently charged flat black holes for
close to unity, and sufficiently charged positively curved black
holes with close to zero, are also unstable. The implication to the
Ho\v{r}ava-Lifshitz holographic superconductor is discussed.Comment: 15 pages, 6 figures. Updated version accepted by Phys. Rev. D, with
corrections to various misprints. References update
The importance of coping and emotion regulation in the occurrence of suicidal behaviour
Research has shown that the use of maladaptive coping strategies and difficulties in regulating mood are linked to increasing risk of suicide. This study measured the impact of coping and emotional regulation on suicidal behaviour in a sample of Asian students. The aim was to determine whether different coping strategies and methods of expressive suppression and cognitive reappraisal would be associated with suicidal behaviour. One hundred and twenty undergraduate students were recruited from The Open University in Hong Kong and all completed questionnaires that measured coping, emotional regulation, and suicidal behaviour. The results showed that increased avoidance coping was associated with increased suicidal behaviour, whereas increased cognitive
reappraisal was associated with reduced risk of suicidal behaviour. Specifically, in an Asian student population, avoidance coping appears to be a risk factor for suicide, whilst cognitive reappraisal may be seen as a positive, protecting strategy.
Keywords: emotion regulation; coping; suicidal behaviour; cognitive reappraisal, expressive suppression
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