Mean field analysis of quantum phase transitions in a periodic optical superlattice

In this paper we analyze the various phases exhibited by a system of ultracold bosons in a periodic optical superlattice using the mean field decoupling approximation. We investigate for a wide range of commensurate and incommensurate densities. We find the gapless superfluid phase, the gapped Mott insulator phase, and gapped insulator phases with distinct density wave orders.Comment: 6 pages, 7 figures, 4 table

Zero Temperature Insulator-Metal Transition in Doped Manganites

We study the transition at T=0 from a ferromagnetic insulating to a ferromagnetic metallic phase in manganites as a function of hole doping using an effective low-energy model Hamiltonian proposed by us recently. The model incorporates the quantum nature of the dynamic Jahn-Teller(JT) phonons strongly coupled to orbitally degenerate electrons as well as strong Coulomb correlation effects and leads naturally to the coexistence of localized (JT polaronic) and band-like electronic states. We study the insulator-metal transition as a function of doping as well as of the correlation strength U and JT gain in energy E_{JT}, and find, for realistic values of parameters, a ground state phase diagram in agreement with experiments. We also discuss how several other features of manganites as well as differences in behaviour among manganites can be understood in terms of our model.Comment: To be published in Europhysics Letter

The Casimir force on a surface with shallow nanoscale corrugations: Geometry and finite conductivity effects

We measure the Casimir force between a gold sphere and a silicon plate with nanoscale, rectangular corrugations with depth comparable to the separation between the surfaces. In the proximity force approximation (PFA), both the top and bottom surfaces of the corrugations contribute to the force, leading to a distance dependence that is distinct from a flat surface. The measured Casimir force is found to deviate from the PFA by up to 15%, in good agreement with calculations based on scattering theory that includes both geometry effects and the optical properties of the material

Benefication of low grade wolramite ore from Degana, Rajasthan

WOLFRAMITE is one of the principal minerals containing tungsten and is considered as a strategic mineral because of its importance and short supply. It is a tungstate of iron and manganese (Fe, Mn) WO4 and generally occurs in prismatic or tabular crystals having a hardness of about 5 and a specific gravity ranging between 7.2 and 7.5. It is usually black in colour and has a good cleavage which causes it to fracture readily into thin flakes It is fairly magnetic. It usually contains 60'6%,', W03, though theoretically it should contain 76.5% WO3

Caffeine, Its Basicity, Acidity, Hydrolysis & Spectrophotometric Assay

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Beneficiation of Low Grade Wolframite Ore from Degana, Rajasthan

Woframite is one of the principal minerals containing tungsten and is considered as a strategic mineral because of its importance and short supply. It is a tungstate of iron and manganese. Low grade wolframite deposits occur in India at Agargaon, Nagpur, Kalimati, Singhbhum, Chennda-pathar, Bankura, jhirpalla, Ahmedabad, Kadavur and Urura-kanad, Tiruchinapalli and on Rawat hill, near Degana, Jodhpur

Combined protein C and protein S deficiency with pregnancy

A 35 year old female patient, married since 8 years, G6P1L1SA4 was registered with our unit since 8th week of gestation. She was a known case of protein C and protein S deficiency diagnosed 7 years ago (thrombotic profile- protein C: 70% normal: 70-100%, protein S: 55% normal: 70/140%, AT-III: 116% normal 70/140%, factor V leiden: no mutation detected) which was detected on evaluation for her bad obstetric history. ACLA was also positive. She was started on injection low molecular weight heparin 0.6 mg s/c OD, in addition to continuing Tb. Aspirin 75 mg which had been started when the pregnancy was registered. Foleys induction was done at 39 weeks of gestation in view of previous LSCS with pre-eclampsia. Emergency LSCS was done in view of previous LSCS with non-progress of labour. Male child weighing 2.4 kg was born which is doing well. A patient having combined deficiency of both factors protein C and protein S is very rare. Anticoagulation therapy is the cornerstone in the management of patients with inherited coagulation defects

Low-temperature far-infrared ellipsometry of convergent beam

Development of an ellipsometry to the case of a coherent far infrared irradiation, low temperatures and small samples is described, including a decision of the direct and inverse problems of the convergent beam ellipsometry for an arbitrary wavelength, measurement technique and a compensating orientation of cryostat windows. Experimental results are presented: for a gold film and UBe13 single crystal at room temperature (lambda=119 um), temperature dependencies of the complex dielectric function of SrTiO3 (lambda=119, 84 and 28 um) and of YBa2Cu3O7-delta ceramic (lambda=119 um).Comment: 14 pages, 6 figure

Improving the Sensitivity of LISA

It has been shown in the past, that the six Doppler data streams obtained LISA configuration can be combined by appropriately delaying the data streams for cancelling the laser frequency noise. Raw laser noise is several orders of magnitude above the other noises and thus it is essential to bring it down to the level of shot, acceleration noises. A rigorous and systematic formalism using the techniques of computational commutative algebra was developed which generates all the data combinations cancelling the laser frequency noise. The relevant data combinations form a first module of syzygies. In this paper we use this formalism for optimisation of the LISA sensitivity by analysing the noise and signal covariance matrices. The signal covariance matrix, averaged over polarisations and directions, is calculated for binaries whose frequency changes at most adiabatically. We then present the extremal SNR curves for all the data combinations in the module. They correspond to the eigenvectors of the noise and signal covariance matrices. We construct LISA `network' SNR by combining the outputs of the eigenvectors which improves the LISA sensitivity substantially. The maximum SNR curve can yield an improvement upto 70 % over the Michelson, mainly at high frequencies, while the improvement using the network SNR ranges from 40 % to over 100 %. Finally, we describe a simple toy model, in which LISA rotates in a plane. In this analysis, we estimate the improvement in the LISA sensitivity, if one switches from one data combination to another as it rotates. Here the improvement in sensitivity, if one switches optimally over three cyclic data combinations of the eigenvector is about 55 % on an average over the LISA band-width. The corresponding SNR improvement is 60 %, if one maximises over the module.Comment: 16 pages, 10 figures, Submitted to Class. Quant. Gravit