Twisted Galilean symmetry and the Pauli principle at low energies

We show the twisted Galilean invariance of the noncommutative parameter, even in presence of space-time noncommutativity. We then obtain the deformed algebra of the Schr\"odinger field in configuration and momentum space by studying the action of the twisted Galilean group on the non-relativistic limit of the Klein-Gordon field. Using this deformed algebra we compute the two particle correlation function to study the possible extent to which the previously proposed violation of the Pauli principle may impact at low energies. It is concluded that any possible effect is probably well beyond detection at current energies.Comment: 16 pages Latex, 2 figures Some modifications made in the abstract, introduction, typographical errors correcte

Dual families of non-commutative quantum systems

We demonstrate how a one parameter family of interacting non-commuting Hamiltonians, which are physically equivalent, can be constructed in non-commutative quantum mechanics. This construction is carried out exactly (to all orders in the non-commutative parameter) and analytically in two dimensions for a free particle and a harmonic oscillator moving in a constant magnetic field. We discuss the significance of the Seiberg-Witten map in this context. It is shown for the harmonic oscillator potential that an approximate duality, valid in the low energy sector, can be constructed between the interacting commutative and a non-interacting non-commutative Hamiltonian. This approximation holds to order 1/B and is therefore valid in the case of strong magnetic fields and weak Landau-level mixing.Comment: 11 pages, no figure

Coupled cluster benchmarks of water monomers and dimers extracted from DFT liquid water: the importance of monomer deformations

To understand the performance of popular density-functional theory (DFT) exchange-correlation (xc) functionals in simulations of liquid water, water monomers and dimers were extracted from a PBE simulation of liquid water and examined with coupled cluster with single and double excitations plus a perturbative correction for connected triples [CCSD(T)]. CCSD(T) reveals that most of the dimers are unbound compared to two gas phase equilibrium water monomers, largely because monomers within the liquid have distorted geometries. Of the three xc functionals tested, PBE and BLYP systematically underestimate the cost of the monomer deformations and consequently predict too large dissociation energies between monomers within the dimers. This is in marked contrast to how these functionals perform for an equilibrium water dimer and other small water clusters in the gas phase, which only have moderately deformed monomers. PBE0 reproduces the CCSD(T) monomer deformation energies very well and consequently the dimer dissociation energies much more accurately than PBE and BLYP. Although this study is limited to water monomers and dimers, the results reported here may provide an explanation for the overstructured radial distribution functions routinely observed in BLYP and PBE simulations of liquid water and are of relevance to water in other phases and to other associated molecular liquids.Comment: 10 pages, 8 figures, Submitted to Journal of Chemical Physics, Related information can be found in http://www.fhi-berlin.mpg.de/th

On how good DFT exchange-correlation functionals are for H bonds in small water clusters: Benchmarks approaching the complete basis set limit

The ability of several density-functional theory (DFT) exchange-correlation functionals to describe hydrogen bonds in small water clusters (dimer to pentamer) in their global minimum energy structures is evaluated with reference to second order Moeller Plesset perturbation theory (MP2). Errors from basis set incompleteness have been minimized in both the MP2 reference data and the DFT calculations, thus enabling a consistent systematic evaluation of the true performance of the tested functionals. Among all the functionals considered, the hybrid X3LYP and PBE0 functionals offer the best performance and among the non-hybrid GGA functionals mPWLYP and PBE1W perform the best. The popular BLYP and B3LYP functionals consistently underbind and PBE and PW91 display rather variable performance with cluster size.Comment: 9 pages including 4 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.htm

On the role of twisted statistics in the noncommutative degenerate electron gas

We consider the problem of a degenerate electron gas in the background of a uniformly distributed positive charge, ensuring overall neutrality of the system, in the presence of non-commutativity. In contrast to previous calculations that did not include twisted statistics, we find corrections to the ground state energy already at first order in perturbation theory when the twisted statistics is taken into account. These corrections arise since the interaction energy is sensitive to two particle correlations, which are modified for twisted anti-commutation relations

आँध्रप्रदेश में विशाखपट्टणम तट पर समुद्री शैवाल काप्पाफाईककस जातियों का समुद्री संवर्धन - संभावनाएं और प्रत्याशाएं

आँध्रप्रदेश में विशाखपट्टणम तट पर समुद्री शैवाल काप्पाफाईककस जातियों का समुद्री संवर्धन - संभावनाएं और प्रत्याशाए

Integration of seaweed (Kappaphycus alvarezii) and pearl oyster (Pinctada fucata) along with Asian seabass (Lates calcarifer) in open sea floating cage off Andhra Pradesh coast

Aquaculture is growing very fast and its growth is expected to continue and it is necessary to supply fish for the ever growing population of our country. In India, fish production and consumption is considered to be important and needs to be promoted. As capture fisheries have almost become stagnant, diversification of aquaculture is highly necessary. Considering the limited scope of freshwater aquaculture and the availability of vast coastline, open sea cage culture gained importance in the present day mariculture practice. Open sea floating cage culture is an alternative sustainable practice for rearing fish and shellfish species and polyculture along with seaweeds may also improve profitability and sustainability. Open sea cage culture is an aquaculture production system where high density of fish is cultured in floating cages. Floating cages are widely used in commercial aquaculture and individual cage units of desired shapes and sizes can be tailored to suit the needs

Assessment of Physicochemical Properties of Flash From TISCO Power Plant, Jamadoba, Jharia Coalfields, Jharkhand, India

This paper deals with some selected physicochemical properties of fly ash collected from a TISCO power plant at Jamadoba, Dhanbad, Jharkhand, India. The physical properties such as bulk density, moisture content, specific gravity, porosity water holding capacity and grain size distribution (sand, silt, clay) were measured, being 0.94gm/cc, 0.73%, 1.84%, 60.25% 76.55% and sand 63.3%, silt 32.6%, clay 2.6% respectively. The chemical properties included in this study were pH, electrical conductivity, organic carbon, cation exchange capacity and available nitrogen. The aim of the present study is to assess the suitability of fly ash of TISCO power plant at vegetation purposes in the low lying areas or degraded land. These physicochemical properties are of also great importance in the backfilling of opencast mines, plantation and reclamation of the abandoned opencast project