2,217 research outputs found
Study of Electromagnetically Induced Transparency using long-lived Singlet States
The long-lived singlet states are useful to study a variety of interesting
quantum phenomena. In this work we study electromagnetically induced
transparency using a two-qubit system. The singlet state acts as a `dark state'
which does not absorb a probe radiation in the presence of a control radiation.
Further we demonstrate that the simultaneous irradiation of probe and control
radiations acts as a dynamical decoupling preserving the singlet state at
higher correlation for longer durations.Comment: 4 pages, 4 figure
Ginzburg-Landau theory of noncentrosymmetric superconductors
The data of temperature dependent superfluid density in
LiPdB and LiPtB [Yuan {\it et al.}, \phrl97, 017006 (2006)]
show that a sudden change of the slope of occur at slightly lower
than the critical temperature. Motivated by this observation, we
microscopically derive the Ginzburg-Landau (GL) equations for
noncentrosymmetric superconductors with Rashba type spin orbit interaction.
Cooper pairing is assumed to occur between electrons only in the same spin
split band and pair scattering is allowed to occur between two spin split
bands. The GL theory of such a system predicts two transition temperatures, the
higher of which is the conventional critical temperature while the lower
one corresponds to the cross-over from a mixed singlet-triplet phase at
lower temperatures to only spin-singlet or spin-triplet (depending on the sign
of the interband scattering potential) phase at higher temperatures. As a
consequence, shows a kink at this cross-over temperature. We
attribute the temperature at which sudden change of slope occurs in the
observed to the temperature . This may also be associated with
the observed kink in the penetration depth data of CePtSi. We have also
estimated critical field near critical temperature.Comment: 7 pages, 1 figur
Using skewness and the first-digit phenomenon to identify dynamical transitions in cardiac models
Disruptions in the normal rhythmic functioning of the heart, termed as
arrhythmia, often result from qualitative changes in the excitation dynamics of
the organ. The transitions between different types of arrhythmia are
accompanied by alterations in the spatiotemporal pattern of electrical activity
that can be measured by observing the time-intervals between successive
excitations of different regions of the cardiac tissue. Using biophysically
detailed models of cardiac activity we show that the distribution of these
time-intervals exhibit a systematic change in their skewness during such
dynamical transitions. Further, the leading digits of the normalized intervals
appear to fit Benford's law better at these transition points. This raises the
possibility of using these observations to design a clinical indicator for
identifying changes in the nature of arrhythmia. More importantly, our results
reveal an intriguing relation between the changing skewness of a distribution
and its agreement with Benford's law, both of which have been independently
proposed earlier as indicators of regime shift in dynamical systems.Comment: 11 pages, 6 figures; incorporating changes as in the published
versio
Efficacy and Safety of Stomatab Capsules® in Improving Oral Health in Recurrent Aphthous Stomatitis: An Open-labeled Clinical Study
Background: Recurrent aphthous stomatitis (RAS) is a common ulcerative disease of the oral mucosa, which is difficult to treat. In Ayurveda, several medicinal plants have been evaluated for their anti-inflammatory and antioxidant effects in many oral diseases as an alternative for modern medicines. Method: A study with open-label, non-comparative single-arm design was conducted to evaluate the efficacy of “Stomatab” capsules in improving oral health in 30 subjects with RAS. The secondary objectives were to assess the improvement in oral health and tolerability of the herbal formulation. Subjects were instructed to take one capsule thrice daily after meals for 14 days. Patients were evaluated at three assessment points: screening and baseline (Visit 1, Day 0) with follow-ups done at Visit 2 (Day 5 ± 2) and Visit 3 at the end of the study (Day 14 ± 2). Results: There was a significant reduction in the mean ulcer size from 3.66 ± 1.27 mm (V1) to 0.64 ± 0.78 (V3). The mean number of ulcers reduced from 1.97 ± 0.72 (V1) to 0.90 ± 0.66 (V3). Significant improvement in ulcer-related symptoms of pain (Ruja), burning sensation (Daha) and redness (Raktavarnata) was noted. The total ulcer symptom scores decreased from 7.67 ± 2.38 (V1) to 0.63 ± 0.56 (V3). No side effects were reported by the study participants. Conclusion: These results show that the polyherbal formulation “Stomatab” capsule is safe and effective for the treatment of RAS
Hierarchical Search Strategy for the Detection of Gravitational Waves from Coalescing Binaries
The detection of gravitational waves from coalescing compact binaries would be a computationally intensive process if a single bank of template wave forms (i.e., a one-step search) is used. We present, in this paper, a method which leads to a large reduction in the computational power required as compared to a one-step search. This method is a hierarchical search strategy involving two template banks. We show that the computational power required by such a two-step search, for an on-line detection of the one-parameter family of Newtonian signals, is 18 of that required when an on-line one-step search is used. This reduction is achieved when signals having a strength of ∼8.8 are required to be detected with a probability of ∼0.95 and an average of one false event per year. We present approximate formulas for the detection probability of a signal and the false alarm probability. We investigate the effect of statistical correlations on these probabilities and incorporate these effects whereever possible. Our numerical results are specific to the noise power spectral density expected for the initial LIGO
Manifestation of helical edge states as zero-bias magneto-tunneling-conductance peaks in non-centrosymmetric superconductors
Helical edge states exist in the mixed spin-singlet and -triplet phase of a
noncentrosymmetric superconductor (NCSS) when the pair amplitude (PA) in the
negative helicity band, , is smaller than the PA in the positive
helicity band, , i.e., when the PA in the triplet component is more
than the same in the singlet component. We numerically determine energies of
these edge states as a function of . The presence
of these edge states is reflected in the tunneling process from a normal metal
to an NCSS across a bias energy : (i) Angle resolved spin conductance (SC)
obeying the symmetry shows peaks when the bias energy
equals the available quasiparticle edge state energy provided . (ii) The total SC, , is zero but modulates with for finite
magnetic field . (iii) The zero bias peaks of and total charge
conductance, , at finite split into two at finite for moderate
. (iv) At zero bias, and increase with and show peaks at
where is a characteristic field.Comment: minor changes; one figure is adde
- …