Chandannagar, India
Chandannagar, India

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Deb R.N.,Chandernagore College
Brazilian Journal of Physics | Year: 2017

We propose a total measure of multi-particle quantum correlation in a system of N two-level atoms (N qubits). We construct a parameter that encompasses all possible quantum correlations among N two-level atoms in arbitrary symmetric pure states and define its numerical value to be the total measure of the net atom-atom correlations. We use that parameter to quantify the total quantum correlations in atomic Schrödinger cat states, which are generated by the dispersive interaction in a cavity. We study the variation of the net amount of quantum correlation as we vary the number of atoms from N=2 to N=100 and obtain some interesting results. We also study the variation of the net correlation, for fixed interaction time, as we increase the number of atoms in the excited state of the initial system, and notice some interesting features. We also observe the behaviour of the net quantum correlation as we continuously increase the interaction time, for the general state of N two-level atoms in a dispersive cavity. © 2017, Sociedade Brasileira de Física.

PubMed | Jadavpur University, Stellenbosch University, Chandernagore College and University of the Balearic Islands
Type: Journal Article | Journal: The journal of physical chemistry. B | Year: 2016

A new cobalt(II) coordination polymer 2 with 1,5 dicyanamide (dca) and a bidentate ligand 3,5-dimethyl-1-(2-pyridyl)pyrazole (pypz) is prepared in a stepwise manner using the newly synthesized one-dimensional linear Co(II) coordination polymer 1 as a precursor. The structural and thermal characterizations elucidate that the more stable complex 2 shows a two-dimensional layer structural feature. Here, Co(II) atoms with 1,5 dicyanamido bridges are linked by the ligand pypz forming a macrocyclic chain that runs along the crystallographic c axis having sql (Shubnikov notation) net topology with a 4-connected uninodal node having point symbol {4(4).6(2)}. The remarkable noncovalent carbon-bonding contacts detected in the X-ray structure of compound 1 are analyzed and characterized by density functional theory calculations and the analysis of electron charge density (atoms in molecules).

Pal P.,Assistant Teacher in Chemistry | Konar S.,Jadavpur University | El Fallah M.S.,University of Barcelona | Das K.,Chandernagore College | And 3 more authors.
RSC Advances | Year: 2015

The synthesis, crystal structures and magnetic property of an uncommon oxalate-containing copper(ii) chain of formula [Cu(L)(Ox)2(H2O)]n (2), where L = 3,5 dimethyl-1-(2′-pyridyl)-pyrazole and a mononuclear Cu(ii) complex [Cu(L)(NO3)2] (1) derived from the same ligand, which can be used as the precursor of compound 2 are reported. The structure of 2 consists of tridentate oxalate-bridged (μ1,2,3) copper(ii) chains, ligand (L) and crystallization water molecules. Variable-temperature magnetic susceptibility measurements of 2 show the occurrence of a weak ferromagnetic interaction through the oxalate bridge [J = +1.95 ± 0.08 cm-1]. The small J value can be interpreted as a consequence of the almost zero overlap between the Cu(ii) ions through the bridging ligand due to the different character (axial and equatorial), giving quasi-orthogonal magnetic orbitals. DFT calculations have been used to rationalize several aspects including the magnetic coupling mechanism and the interesting noncovalent interactions observed in the solid state architecture of compounds 1 and 2. This journal is © The Royal Society of Chemistry.

Ganguly S.,Chandernagore College | Banerjee P.,Saha Institute of Nuclear Physics | Dey A.,Variable Energy Cyclotron Center | Bhattacharya S.,Saha Institute of Nuclear Physics
Pramana - Journal of Physics | Year: 2011

In the present work, the excited states of 113Sb were populated in the 100Mo(20Ne, p6n) reaction at a beam energy of 136 MeV. States only up to 59/2̄ were observed in the δJ = 2 band. Mean lifetimes for the five states (from 4460 to 7998 keV) were measured for the first time using Doppler shift attenuation method. An upper limit of the lifetime (0.14 ps) was estimated for the 9061 keV, 47/2̄ state. The B(E2) values, derived from the present lifetime results, correspond to a large quadrupole deformation of β2 = 0.32. The observed reduction in the experimental B(E2) values for the 918.4 keV (spin 39/2̄ → 35/2̄) and 985 keV (spin 43/2. → 39/2̄) transitions may be interpreted as due to the proton alignement in the g7/2 orbital. The dynamic moment of inertia was observed to be about half of the rigid body value at the highest observed frequency. © Indian Academy of Sciences.

Ghorai A.,Chandernagore College
Defect and Diffusion Forum | Year: 2012

A brief sketch of different models for the calculation of defect parameters in metals and alloys, comparison of data and limitations has been reviewed here; especially relaxations due to a vacancy type of point defect, its formation, migration, activation energies and related other parameters based upon the present experimental status. The models reviewed are the Bond model, Continuum model, Semi-discrete model, Jellium model, Thermodynamic model, Lattice Statics model, Atomistic Continuum model and Pseudopotential model. The main thrust concerns the last model. The Taylor, Vashishta and Singwi, Harrison, Kleinmann and King and Kutler form of exchange and correlation function are almost similar, give moderate results and may be trusted for better results. © (2012) Trans Tech Publications, Switzerland.

Banerjee P.,Saha Institute of Nuclear Physics | Ganguly S.,Chandernagore College | Pradhan M.K.,Saha Institute of Nuclear Physics | Sharma H.P.,Banaras Hindu University | And 3 more authors.
Physical Review C - Nuclear Physics | Year: 2011

The two ΔI=1 bands in In111, built upon the 3461.0 and 4931.8 keV states, have been studied. The bands were populated in the reaction Mo100(F19,α4nγ) at a beam energy of 105 MeV. Mean lifetimes of nine states, four in the first and five in the second band, have been determined for the first time from Doppler shift attenuation data. The deduced B(M1) rates and their behavior as a function of level spin support the interpretation of these bands within the framework of the shears mechanism. The geometrical model of Machiavelli has been used to derive the effective gyromagnetic ratios for the two bands. © 2011 American Physical Society.

We quantify multiparticle quantum entanglement in a system of N two-level atoms interacting with a squeezed vacuum state of the electromagnetic field. We calculate the amount of quantum entanglement present among one hundred such two-level atoms and also show the variation of that entanglement with the radiation field parameter. We show the continuous variation of the amount of quantum entanglement as we continuously increase the number of atoms from N = 2 to N = 100. We also discuss that the multiparticle correlations among the N two-level atoms are made up of all possible bipartite correlations among the N atoms. © 2016, Springer Science+Business Media New York.

Mondal P.,Chandernagore College
Operational Research | Year: 2016

Zero-sum two-person finite undiscounted (limiting ratio average) semi-Markov games are considered where the transition probabilities and the transition times are controlled by a fixed player in all states. We prove that if such a game is unichain, the value and optimal stationary strategies can be obtained from an optimal solution of a linear programming algorithm for the associated undiscounted unichain single controller stochastic game (obtained by a data transformation method). The single controller undiscounted unichain semi-Markov games have been formulated as a linear complementarity problem and solved using a stepwise principal pivoting algorithm. We provide necessary and sufficient conditions for such games to be completely mixed (i.e., every optimal stationary strategy for each player assigns a positive probability to every action in every state). Some properties analogous to completely mixed matrix games are also established in this paper. © 2016 Springer-Verlag Berlin Heidelberg

Ghorai A.,Chandernagore College
Defect and Diffusion Forum | Year: 2010

In fast diffusion, the impurity diffusion coefficient is much greater than the self-diffusion coefficient. The I - V pair mechanism is here considered to explain fast diffusion. Formulations for the formation of the I - V pair are based upon pseudopotential theory. © (2010) Trans Tech Publications.

Ganguly G.,Chandernagore College | Mukhopadhyay R.,University of Burdwan
Proceedings of the National Academy of Sciences India Section B - Biological Sciences | Year: 2012

Sikkim is rich in pteridophyte diversity but there are no distributional maps in grid cell manner for assessing the species-rich areas of pteridophytes. In total 127 pteridophytes were collected from different parts of Southern Sikkim within the range of 420-3,573 m altitudes; they were identified and plotted in 6 9 6 km grid cell maps. 'Epiphyte-richness' as well as 'Species-richness' maps were prepared. Altitude-wise distributions of pteridophytes were also determined. From the grid cell studies of 28 different places of Southern Sikkim, it was revealed that Central Sikkim was richer in the number of pteridophytes than the Southern, Western and Eastern parts of Sikkim. Altitudinally, the middle hill forest areas (1,500-2,700 m) possess the ideal climatic conditions for the growth of pteridophytes as is evidenced by the occurrence of a large number of pteridophytes in this zone. Maenum, Versey, Pelling and Gangtok are very rich in epiphytic and terrestrial species of pteridophytes. This overview of knowledge regarding pteridophytes distribution, in relation to climatic conditions, in Southern Sikkim will be of much help in formulating conservation strategies. © The National Academy of Sciences, India 2012.

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