2,783 research outputs found
Effect of nonlinearity on the dynamics of a particle in dc field-induced systems
Dynamics of a particle in a perfect chain with one nonlinear impurity and in
a perfect nonlinear chain under the action of dc field is studied numerically.
The nonlinearity appears due to the coupling of the electronic motion to
optical oscillators which are treated in adiabatic approximation.
We study for both the low and high values of field strength. Three different
range of nonlinearity is obtained where the dynamics is different. In low and
intermediate range of nonlinearity, it reduces the localization. In fact in the
intermediate range subdiffusive behavior in the perfect nonlinear chain is
obtained for a long time. In all the cases a critical value of nonlinear
strength exists where self-trapping transition takes place. This critical value
depends on the system and the field strength. Beyond the self-trapping
transition nonlinearity enhances the localization.Comment: 9 pages, Revtex, 6 ps figures include
Does the QCD plasma contain propagating gluons?
Comparison of two appropriately chosen screening masses of colour singlet
operators in the pure glue QCD plasma indicates that at sufficiently high
temperature it contains a weakly-interacting massive quasi-particle with the
quantum numbers of the electric gluon. Still in the deconfined phase, but
closer to T_c, the same mass ratio is similar to that at zero temperature,
indicating that the propagating modes are more glueball-like, albeit with a
lower scale for the masses. We observe a continuity between these two regimes.Comment: 4 pages, 3 figure
Neutral current effects in parity violating nuclear force
The measurements of the ΔI= 1 part of the parity violating nuclear force when combined with information on neutral current couplings from neutriro scattering and pion production experiments allow an estimate of the isoscalar admixture in the neutral current if it nas a vector axial-vector structure has been shown
Antifungal activities and chemical characterization of Neem leaf extracts on the growth of some selected fungal species in vitro culture medium.
The efficacy of different extracts of neem leaf on seed borne fungi
Aspergillus , Rhizopus and chemical characterization of the neem
leaf extracts were studied in vitro on the culture medium. The growth
of both the fungal species was inhibited significantly (p<0.01) and
controlled with both alcoholic and water extract of all ages and of the
concentrations used. The alcoholic extracts of neem leaf was most
effective in comparison to aqueous extract for retarding the growth of
Rhizopus and Aspergillus. The crude aqueous and alcoholic leaf extracts
of neem was more effective in inhibitions of growth of the fungi
Aspergillus in comparison to inhibitory effects on Rhizopus growth in
the artificial culture medium. Leaf extracts of neem which are cheap
and environmentally safe are promising for protecting crop species
against the fungal infestation and leading towards improvement of the
crop in terms of yield and productivity. @ JASE
Wave attenuation model for dephasing and measurement of conditional times
Inelastic scattering induces dephasing in mesoscopic systems. An analysis of
previous models to simulate inelastic scattering in such systems is presented
and also a relatively new model based on wave attenuation is introduced. The
problem of Aharonov-Bohm(AB) oscillations in conductance of a mesoscopic ring
is studied. We have shown that conductance is symmetric under flux reversal and
visibility of AB oscillations decay to zero as function of the incoherence
parameter, signalling dephasing. Further wave attenuation is applied to a
fundamental problem in quantum mechanics, i.e., the
conditional(reflection/transmission) times spent in a given region of space by
a quantum particle before scattering off from that region.Comment: 8 pages, 6 figures. Based on presentations by A. M. J and C. B at the
2nd Winter Institute on Foundations of Quantum theory, Quantum Optics and QIP
held at S N Bose National Centre for Basic Sciences, Kolkata, India, from
January 2-11, 200
Discrimination in the University in India
Despite changes to the status of women in India, the strong patriarchal traditions continue to shape the way that women take their place in Indian society. There are more opportunities for women in India today, inclusive of political, financial and working opportunities, but it is difficult not to notice that India is still a male dominated society
Performance of Indian Manufacturing in the Post Reform Period
Many emerging countries in recent decades have relied on a development strategy that focused primarily on promoting the manufacturing sector and the exports of manufactured goods. However, an acceleration of growth of output and employment in manufacturing has eluded India. This is despite the fact that the central focus of the reforms in the 1980s and 1990s was to unshackle the manufacturing sector. Instead it is the services sector which has grown rapidly, contributing about two-third of GDP growth in recent years. This paper discusses the reasons behind the modest performance of the manufacturing sector in India post reforms. It argues that there are many factors that have inhibited the growth of industrial sector in India. One major factor is the rigid and strict labor laws which have affected the industrial performance in a number of ways, by keeping the size of the establishments small, by not encouraging the production of labor intensive goods, by pushing activities to the unorganized sector, and by keeping the Indian industry uncompetitive. Besides the labor laws other factors that are responsible for the modest performance of the manufacturing sector include difficulty in the acquisition of land for industrial use, inadequate financing and infrastructure, and cumbersome business climate. The paper presents arguments and evidence which shows the importance of these factors
Comparison between the two models of dephasing in mesoscopic systems
In mesoscopic systems to study the role of inelastic scattering on the phase
coherent motion of electrons two phenomenological models have been proposed. In
the first one, due to B\"uttiker, one adds a voltage probe into the system (or
in the scattering matrix). The second model invokes the complex (or optical)
potential in the system Hamiltonian. Studying a simple geometry of a metallic
loop in the presence of Aharonov-Bohm magnetic flux, we show that the two probe
conductance is symmetric in the reversal of the magnetic field in B\"uttiker's
approach. Whereas the two probe conductance within the complex potential model
is asymmetric in the magnetic flux reversal contrary to the expected behavior.Comment: 11 pages RevTex, 4 figures inculded, Communicated to PR
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