7,616 research outputs found
Mesoscopic Superposition of States with Sub-Planck Structures in Phase Space
We propose a method using the dispersive interaction between atoms and a high
quality cavity to realize the mesoscopic superposition of coherent states which
would exhibit sub-Planck structures in phase space. In particular we focus on a
superposition involving four coherent states. We show interesting interferences
in the conditional measurements involving two atoms.Comment: 4-page 3-figur
Cosmic ray intensity distribution perpendicular to solar equatorial plane at 1 A.U. during 1978-83
The distribution of cosmic ray intensity perpendicular to solar equatorial plane, was investigated by using its yearly variation with respect to the heliolatitudinal position of the Earth, for the two intervals 1978 to 1980 and 1981 to 1983. The monthly mean values of two high latitude stations along with the solar and geomagnetic indices are used to derive the cosmic ray intensity distribution free from the changes due to variation in solar activity. The correction is found to be significant only during the interval 1976 to 1980. The results indicate a significant linear increase in cosmic ray intensity from north to south of solar equator, contrary to that observed during 1973 to 1975. No symmetrical gradients are found during the period of study, in agreement with earlier results
Optimising Forage Production on Degraded Lands in the Dry Tropics Through Silvopastoral Systems
In India, 187 M ha out of a total area of 328 M ha face the problem of land degradation, mostly due to water and wind erosion. The problems are aggravated by poor land cover and increasing pressure of human and livestock populations. There is over-exploitation of the scarce resources of forage and firewood. Several techniques, including watershed based silvopastoral land use have been proposed (Patil & Pathak, 1977). Tree, grass and legume based systems have been tried after land treatment to reduce runoff and soil loss while meeting the forage needs of the livestock and firewood for cooking in many studies (Debroy & Pathak, 1983). Results of an operational research project on silvopastoral systems are reported in this paper
Optimising Forage Production on Degraded Lands in the Dry Tropics Through Silvopastoral Systems
In India, 187 M ha out of a total area of 328 M ha face the problem of land degradation, mostly due to water and wind erosion. The problems are aggravated by poor land cover and increasing pressure of human and livestock populations. There is over-exploitation of the scarce resources of forage and firewood. Several techniques, including watershed based silvopastoral land use have been proposed (Patil & Pathak, 1977). Tree, grass and legume based systems have been tried after land treatment to reduce runoff and soil loss while meeting the forage needs of the livestock and firewood for cooking in many studies (Debroy & Pathak, 1983). Results of an operational research project on silvopastoral systems are reported in this paper
Quantum random walk of two photons in separable and entangled state
We discuss quantum random walk of two photons using linear optical elements.
We analyze the quantum random walk using photons in a variety of quantum states
including entangled states. We find that for photons initially in separable
Fock states, the final state is entangled. For polarization entangled photons
produced by type II downconverter, we calculate the joint probability of
detecting two photons at a given site. We show the remarkable dependence of the
two photon detection probability on the quantum nature of the state. In order
to understand the quantum random walk, we present exact analytical results for
small number of steps like five. We present in details numerical results for a
number of cases and supplement the numerical results with asymptotic analytical
results
Enhanced grain surface effect on magnetic properties of nanometric La0.7Ca0.3MnO3 manganite : Evidence of surface spin freezing of manganite nanoparticles
We have investigated the effect of nanometric grain size on magnetic
properties of single phase, nanocrystalline, granular La0.7Ca0.3MnO3 (LCMO)
sample. We have considered core-shell structure of our LCMO nanoparticles,
which can explain its magnetic properties. From the temperature dependence of
field cooled (FC) and zero-field cooled (ZFC) dc magnetization (DCM), the
magnetic properties could be distinguished into two regimes: a relatively high
temperature regime T > 40 K where the broad maximum of ZFC curve (at T = Tmax)
is associated with the blocking of core particle moments, whereas the sharp
maximum (at T = TS) is related to the freezing of surface (shell) spins. The
unusual shape of M (H) loop at T = 1.5 K, temperature dependent feature of
coercive field and remanent magnetization give a strong support of surface spin
freezing that are occurring at lower temperature regime (T < 40 K) in this LCMO
nanoparticles. Additionally, waiting time (tw) dependence of ZFC relaxation
measurements at T = 50 K show weak dependence of relaxation rate [S(t)] on tw
and dM/dln(t) following a logarithmic variation on time. Both of these features
strongly support the high temperature regime to be associated with the blocking
of core moments. At T = 20 K, ZFC relaxation measurements indicates the
existence of two different types of relaxation processes in the sample with
S(t) attaining a maximum at the elapsed time very close to the wait time tw =
1000 sec, which is an unequivocal sign of glassy behavior. This age-dependent
effect convincingly establish the surface spin freezing of our LCMO
nanoparticles associated with a background of superparamagnetic (SPM) phase of
core moments.Comment: 41 pages, 10 figure
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