3,360 research outputs found
Superfluid and Fermi liquid phases of Bose-Fermi mixtures in optical lattices
We describe interacting mixtures of ultracold bosonic and fermionic atoms in
harmonically confined optical lattices. For a suitable choice of parameters we
study the emergence of superfluid and Fermi liquid (non-insulating) regions out
of Bose-Mott and Fermi-band insulators, due to finite Boson and Fermion
hopping. We obtain the shell structure for the system and show that angular
momentum can be transferred to the non-insulating regions from
Laguerre-Gaussian beams, which combined with Bragg spectroscopy can reveal all
superfluid and Fermi liquid shells.Comment: 4 pages, 2 figure
See-saw fermion masses in an SO(10) GUT
In this work we study an SO(10) GUT model with minimum Higgs representations
belonging only to the 210 and 16 dimensional representations of SO(10). We add
a singlet fermion S in addition to the usual 16 dimensional representation
containing quarks and leptons. There are no Higgs bi-doublets and so charged
fermion masses come from one-loop corrections. Consequently all the fermion
masses, Dirac and Majorana, are of the see-saw type. We minimize the Higgs
potential and show how the left-right symmetry is broken in our model where it
is assumed that a D-parity odd Higgs field gets a vacuum expectation value at
the grand unification scale. From the renormalization group equations we infer
that in our model unification happens at 10^{15} GeV and left-right symmetry
can be extended up to some values just above 10^{11} GeV. The Yukawa sector of
our model is completely different from most of the standard grand unified
theories and we explicitly show how the Yukawa sector will look like in the
different phases and briefly comment on the running of the top quark mass. We
end with a brief analysis of lepton number asymmetry generated from the
interactions in our model.Comment: 30 pages, 10 figure
Superfluid and Mott Insulating shells of bosons in harmonically confined optical lattices
Weakly interacting atomic or molecular bosons in quantum degenerate regime
and trapped in harmonically confined optical lattices, exhibit a wedding cake
structure consisting of insulating (Mott) shells. It is shown that superfluid
regions emerge between Mott shells as a result of fluctuations due to finite
hopping. It is found that the order parameter equation in the superfluid
regions is not of the Gross-Pitaeviskii type except near the insulator to
superfluid boundaries. The excitation spectra in the Mott and superfluid
regions are obtained, and it is shown that the superfluid shells posses low
energy sound modes with spatially dependent sound velocity described by a local
index of refraction directly related to the local superfluid density. Lastly,
the Berezinskii-Kosterlitz-Thouless transition and vortex-antivortex pairs are
discussed in thin (wide) superfluid shells (rings) limited by three (two)
dimensional Mott regions.Comment: 11 pages, 9 figures
Traditional Rural Wetlands in Haryana State of India Are Currently Confronting Multicornered Threats Leading to Extinction Sooner Than Later
The most serious threat to traditional rural ponds in Haryana is associated with transformed societal behavioural patterns, ethics, values and life style, amongst several others. The siltation of ponds with adjoining areas, soil coming in with rain water is a very serious cause of stratification of rural ponds. Also contracting of village community land for sun drying of cow dung cakes inspires villagers to overload periphery of each pond with cow dung turning the premises into grave-yard of dung. This dung is the major source of polluting pond water into blackish water with high load of organic matter. Moreover, it leads to over excessive eutrophication. Building of major highways and connectivity roads have resulted into compartmentalization and degradation of village ponds. Inhabitation of peripheral village ponds boundaries by lower section of society for dwelling purposes is more threat to wetlands. The indifferent inclination of villagers towards silted ponds drenched in bad odour and blackish sludge is the story of 80% of the cases. The total blockage of run-off rainy water towards the natural age old rural ponds due to obstruction by way of human inhabitation has resulted into desertification of shallow water sheet in 90% of the cases. The oblivion of harvesting dried silt in summer for brick making has spelled doom for the ponds turning them into flat ground through successive decades and so on. The water quality in all ponds was overshooting the decaying stage due to the continuous mixing of cow dung drenched rainy water. Over excessive USAge of ponds for bathing of cattle, dumping of cow dung and rotten vegetables waste has turned ponds into live sinks of dirt, garbage and rural dairy wastes. Majority of village ponds are now out of existence or in deep black sludge laden or converted into Fish-Farming wetlands. The present studies have indicated that Winter migratory birds like Greylag Goose Anser anser, Bar-headed Goose Anser indicus, Mallard Anas platyrhynchos, Gadwall Anas strepera, Northern Shoveller Anas clypeata, Northern Pintail Anas acuta, Garganey Anas querquedula, Common Teal Anas crecca, Common Pochard Aythya ferina, Tufted Pochard Aythya fuligula, Common Coot Fulica atra, Little Ringed Plover Charadrius dubius, Kentish Plover Charadrius alexandrines, Spotted Redshank Tringa erythropus, Common Redshank Tringa tetanus, Marsh Sandpiper Tringa stagnatilis, Wood Sandpiper Tringa glareola and Pied Avocet Recurivirostra avosetta arrive in the extremely dilapidated rural ponds in Haryana from far off places including Russia, Siberia, China, and Caspian region, east Asia each winter season without any break. As such the extinction of ponds in Haryana directly threatens global avian biodiversity
Loss-Induced Limits to Phase Measurement Precision with Maximally Entangled States
The presence of loss limits the precision of an approach to phase measurement
using maximally entangled states, also referred to as NOON states. A
calculation using a simple beam-splitter model of loss shows that, for all
nonzero values L of the loss, phase measurement precision degrades with
increasing number N of entangled photons for N sufficiently large. For L above
a critical value of approximately 0.785, phase measurement precision degrades
with increasing N for all values of N. For L near zero, phase measurement
precision improves with increasing N down to a limiting precision of
approximately 1.018 L radians, attained at N approximately equal to 2.218/L,
and degrades as N increases beyond this value. Phase measurement precision with
multiple measurements and a fixed total number of photons N_T is also examined.
For L above a critical value of approximately 0.586, the ratio of phase
measurement precision attainable with NOON states to that attainable by
conventional methods using unentangled coherent states degrades with increasing
N, the number of entangled photons employed in a single measurement, for all
values of N. For L near zero this ratio is optimized by using approximately
N=1.279/L entangled photons in each measurement, yielding a precision of
approximately 1.340 sqrt(L/N_T) radians.Comment: Additional references include
Description of Avian Bio-Diversity of Damdamma Jheel in Gurgaon District in Haryana, India
Damdamma Jheel is a wetland of impressive potentials of harboring rich avian bio-diversity in the accompaniment of enhanced habitat reconstruction and improvement. It is located in the National Capital Region, nearby Sohana town in Gurgaon district in Haryana merely 45 Kms from Dhaula Kuan in New Delhi. At present, compared to Sultanpur National Park, it is confronting neglect. Considering its positive features of terrain, water sheet, it has the qualities of being a rich habitat for birds of all hues including the winter migratory birds. The present studies focus attention on its avian biodiversity as well as its own degraded form and structure. In all, 128 species of birds belonging to 15 orders and 41 families could be enlisted. Order Passeriformes is the predominant one having 54 species, followed by Charadriiformes (14 Species) and Ciconiiformes (12 Species). The prominent winter migratory birds observed from Damdamma Jheel include Asian Openbill Stork Anastomus oscitans, Eurasian Spoonbill Platalea leucorodia, Northern Shoveller Anas clypeata, Northern Pintail Anas acuta, Common Teal Anas crecca, Common Pochard Aythya ferina, Gadwall Anas strepera, Spot-billed Duck Anas poecilorhyncha, Spotted Redshank Tringa erythropus, Common Redshank Tringa tetanus, Common Greenshank Tringa nebularia, Kentish Plover Charadrius alexandrinus, White-tailed Lapwing Vanellus leucurus, Marsh Sandpiper Tringa stagnatilis, Wood Sandpiper Tringa glareola, Common Sandpiper Actitis hypoleucos, White Wagtail Motacilla alba and Yellow Wagtail Motacilla flava. The lake is suffering from water scarcity considering its capacity and potential to have more water. The periphery towards east is plagued by the growth of peats. The very fact that in October 2012, a large group of Openbill Stork (Nearly 70-80) has already arrived at Damdamma Lake since September-2012 indicates that it is the largest HARBOUR of Open-bill Stork in Haryana. Also, Eurasian Spoonbills were seen in a group 10-12, again the largest in Haryana. It is argued in this paper, that Damdamma is the pride lake of Haryana and prime harbor for uncommon winter migratory birds like Open-bill Stork and Eurasian Spoonbill must be the prime place for habitat reconstruction by Ministry of Environment and Forest, Govt. of India in conjunction with Govt. of Haryana with the active contributions by WWF (India) to add to the might vastness of this lake an element of grace and glory so as to conserve the winter migratory birds during their sojourn in India. In addition, it will be one nodal point to include Sultanpur National Park, Badkhal Lake, Bhindawas and Keoladeo National Park as an eco-tourism rectangle with provision for night halt
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