An International Research Journal

AJP

SSN : 0971 - 3093

Vol 25, No 6, June 2016

25th Anniversary Year of AJP-2016

Accepted papers: Vol 25, No 6, 2016

Special Section on

“Static and dynamic---cold atoms and molecules"

 


Asian Journal of Physics                                                                                                                    Vol. 25 No 6 (2016) 00-00


Dynamics of atomic and molecular solitary waves in atom-molecular hybrid Bose-Einstein condensates coupled byMagnetic Feshbach Resonance: Role of induced decays of Feshbach Molecules

 

Krishna Rai Dastidar, and Deb Shankar Ray

Indian Association for the Cultivation of Science, Kolkata-700 032, India

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Dynamics of atomic and molecular bright solitons in a hybrid atom-molecular BEC (Bose Einstein Condensate) system of 85Rb coupled through Magnetic Feshbach Resonance (MFR) has been investigated. By solving the time  independent atom-molecular coupled equations, the initial atomic and molecular wavefunctions were obtained and the dynamics of the initial atomic and molecular waves in a spherical one-dimensional trap were studied by solving the time-dependent atom-molecular coupled equations. During evolution two types of induced or stimulated decays of the feshbach molecules were switched on. These two types of stimulated decays of the feshbach molecules (i) to the two-atom continuum and (ii) to the bound level of the lowest hyperfine state of the molecule were induced by laser/RF (Radio Frequency) fields. Hence the strength of these two induced decays can be controlled by varying the laser/RF field parameters e.g. intensity, detuning etc. It is found that depending on the relative strength of these two types of stimulated or induced decays initial atomic and molecular waves assume solitonic nature as bright solitons during evolution and the stability of these solitonic waves can be achieved by controlling the relative strength of induced decays in two different channels. It is shown that these two induced decays lead to the formation of stable atomic and molecular solitons by suppressing the initial oscillations and instability in the atom-molecular coupled system of 85Rb atoms. © Anita Publications. All rights reserved.

Total Refs: 52

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Asian Journal of Physics                                                                                                                    Vol. 25 No 6 (2016) 00-00

 

Dispersion coefficients for the interaction of inert gas atoms with alkali and alkaline earth ions and 

alkali atoms with their singly ionized ions

 

Sukhjit Singha, KiranpreetKaura, B K Sahoob* and Bindiya Aroraa

aDepartment of Physics, Guru Nanak Dev University, Amritsar, Punjab-143 005, India

bTheoretical Physics Division, Physical Research Laboratory, Navrangpura, Ahemadabad-380 009, India

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We report the dispersion coefficients for the interacting inert gas atoms with the alkali ions, alkaline earth ions and alkali atoms with their singly charged ions. We use our relativistic coupled-cluster method to determine dynamic dipole and quadrupole polarizabilities of the alkali atoms and singly ionized alkaline earth atoms, whereas a relativistic random phase approximation approach has been adopted to evaluate these quantities for the closed-shell configured inert gas atoms and the singly and doubly ionized alkali and alkaline earth atoms, respectively. Accuracies of these results are adjudged from the comparison of their static polarizability values with their respective experimental results. These polarizabilities are further compared with the other theoretical results. Reason for the improvement in the accuracies of our estimated dispersion coefficients than the data listed in [At. Data and Nucl.Data Tables 101, 158 (2015)] are discussed. Results for some of the atom-ion interacting systems were not available earlier, these results and the other reported improved results will be very useful for the comprehensive understanding of the collisional physics involving these atom-atom and atom-ion interactions in the cold atom and atom-ion hybrid trapping experiments at the low-temperature regime.© Anita Publications. All rights reserved.

Total Refs: 60

Dispersion coeffcients for the interaction of inert gas atoms with....pdf
Sukhjit Singh, Kiranpreet Kaur, B K Sahoo and Bindiya Arora

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Asian Journal of Physics                                                                                                                      Vol. 25 No 6 (2016) 00-00

 

A method to solve nonlinear Schrodinger equation using Riccati equation

 

Vivek M Vyas1, Rama Gupta2, C N Kumar3 and Prasanta K Panigrahi4

1Chennai Mathematical Institute, SIPCOT IT Park, Siruseri- 603 103, India

2Department of Physics, DAV University, Jalandhar- 144 008, India

3Department of Physics, Panjab University, Chandigarh- 160 014, India

4Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia- 741 246, India

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A method to find exact solutions to nonlinear Schrodinger equation, defined on a line and on a plane, is found by connecting it with second order linear ordinary differential equation. The connection is essentially made using Riccati equation. Generalisation of several known solutions is found using this method, in case of nonlinear Schrodinger equation defined  on a line. This method also yields non-singular and singular vortex solutions, when applied to nonlinear Schrodinger equation on a plane.© Anita Publications. All rights reserved.

Total Refs: 23

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Asian Journal of Physics                                                                                                               Vol 25, No 6, (2016) 00-00


 Experimental and DFT vibrational spectra and structure of 3-Iodopyridine


Nandini V. Aralikatti ,  J. Tonannavar , Jayashree Yenagi †*

Vibrational Spectroscopy Group, Department. of Physics

 Karnatak University, Dharwad-580003, India

     ‡Department. of Physics, Kittel  Science College, Dharwad-580001, India

                                        *e-mail:jyenagi.phys.kud@gmail.com;  Tel:+9108362215316

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A complete review and reassignment of the vibrational spectra of 3-Iodopyridine have been proposed. The measured vibrational spectra include IR (3500 – 400 cm-1) and Raman (3500–100 cm-1) spectra. Geometry and harmonic vibrational frequencies of 3-Iodopyridine have been computed by employing a batch of four density functional theoretical methods(DFTs) - ab initio RHF, hybrid - B3LYP, B3PW91 and MP2 methods using the LANL2DZ basis set. Analysis has shown that some vibrational modes of 3-Iodopyridine change both in intensity and frequency with respect to Pyridine, mono-substituted halo-pyridines including 2-Iodopyridine. Absence of two characteristic C-H stretching modes near 3069 and 3051cm-1 as IR and Raman bands is attributed to the weakening of the sp2 hybridization in the pyridine ring. The C-H bending modes near 1450 -1400 cm-1 are IR strong. The characteristically strong Raman ring breathing mode near 1100 – 900 cm-1 is IR strong at 1007 cm-1 but Raman weak, suggesting ring strain. However, a trigonal mode near 1038 cm-1 and C-I stretching at 267 cm-1 are Raman strong.  Of the four DFT methods, the B3LYP/LANL2DZ level has produced spectral results in very good agreement with the experiment. Further, the LANL2DZ basis set with effective core potential representation for the heavy Iodine is proved satisfactory for 3-Iodopyridine.©Anita Publications. All rights reserved.

Keywords: 3-Iodopyridine, IR, Raman, B3LYP, B3PW91, MP2, LANL2DZ

Total Refs: 29

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Asian Journal of Physics                                                                                                               Vol 25, No 6, (2016) 00-00


Gravitation and Radiation


Francis T S Yu

Emeritus Evan Pugh Professor of Electrical Engineering

Penn State University, University Park, PA 16802, USA

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Gravitation is one of the most intriguing forces in space that govern all the interstellar spectacles motion in this universe. In this article we have shown there is a profound relationship between gravitational fields with respect to its converted energy. Since time is an inevitable element in every aspect of science; we have developed a partial differential equation from Einstein’s energy equation in which we show that gravitational field can be coupling with its diverging energy radiation.  We have also shown that energy to mass conversion in principle is conceivable by means of energy convergent operation (i.e., in-flow) into a unit space. In fact this could have been happen by the eventuality of a black hole explosion, as remains to be observed. .©Anita Publications. All rights reserved.

Keywords: Gravitation, Interstellar spectacles, Einstein’s energy equation, Black hole

Total Refs: 11

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Asian Journal of Physics                                                                                                               Vol 25, No 6, (2016) 00-00


Cold ion based geometric phase generation: a tool or non-optical quantum computation


Debashis De Munshi

Centre for Quantum Technologies, National University of Singapore, Singapore - 117543

 Manas Mukherjee

Centre for Quantum Technologies, National University of Singapore, Singapore - 117543 and

 Department of Physics, National University of Singapore, Singapore - 117551

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Abelian and Non-Abelian evolution of a quantum system manifests differently in the geometric phase acquired by the system under such evolutions. In this work, we develop the theory and study the properties of a experimentally realizable spin system which can be driven continuously from Abelian to non-Abelian geometry and vice versa. This unified framework allows us to characterize the parameter dependence of the geometric phase originating from different geometry of the Hilbert space. As geometric phase is key to robust quantum computation, we quantify the noise related to geometric phase and its dependence on external parameters. As a consequence we find the noise to be entirely dependent on the geometry of the system. © Anita Publications. All rights reserved.

Total Refs: 18

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Asian Journal of Physics                                                                                                               Vol 25, No 6, (2016) 00-00


Bosons in a trap: phases and dynamics

K Sengupta

Theoretical Physics Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata

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We review a hopping expansion technique for studying phases and phase transition of strongly interacting bosons in an optical lattice in the presence of a harmonic trap. The advantage of this technique is that it allows one to study both the equilibrium phase diagram and non-equilibrium dynamics of the bosons at same footing. The technique also enables one to treat quantum fluctuations of the bosons systematically and leads to a the boson phase diagram which is almost as accurate as that found by quantum Monte Carlo. In addition, it predicts several novel non-equilibrium effects which are missed by mean-field theory. © Anita Publications. All rights reserved.

Keywords: Bosons; Phase transition; Monte Carlo

Total Refs: 29

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Asian Journal of Physics                                                                                                               Vol 25, No 6, (2016) 00-00


Two-photon photoassociation of a pair of interacting atoms in a trap

 

Partha Goswami1, Arpita Pal1, Subrata Saha1 and Bimalendu Deb1;2

1Department of Materials Science,

Indian Association for the Cultivation of Science (IACS), Jadavpur, Kolkata-700 032, India,

2Raman Centre for Atomic, Molecular and Optical Sciences,

IACS, Jadavpur, Kolkata-700 032, India.

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We show that it is possible to generate coherent coupling between the discreet eigenstates of a pair of interacting atoms in a trap by two-photon photoassociation, via adiabatic elimination of the excited molecular state involved in the PA transitions. We develop a fully quantum mechanical treatment of the problem and present a dressed state description for the eigenstates. This coherent coupling is important for manipulating the relative motional states of the two atoms. © Anita Publications. All rights reserved.

Keywords: Photoassociation (PA);Ultracold atoms; Coherent coupling

Total Refs: 29

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Asian Journal of Physics                                                                                                               Vol 25, No 6, (2016) 00-00


Vibrational study of Azobenzene: Comparative study with ab-initio calculation

 

Th.Gomti Devi

Department of Physics, North-Eastern RegionalInstitute of Science and Technology,

Arunachal  Pradesh-791 109, India

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Azobenzene is a photochromic molecule which exhibits a reversible isomerisation process between its trans and cis isomers of different stability. An investigation has been conducted of the effects of temperature on intensity and position of Raman bands of N=N and C-N stretching mode of Azobenzene (AZBN). It was found that both the N=N stretching and the C-N stretching mode of Raman band shape shifts to lower frequency region with the increase in temperature. Ab initio calculation for geometry optimization and vibrational wavenumber calculation have been performed to support the experimental findings.  © Anita Publications. All rights reserved.                                                         

 Key words : Azobenzene, isomerisation, IR and Raman spectra ab-initio

Total Refs: 22

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Asian Journal of Physics                                                                                                               Vol 25, No 6, (2016) 00-00


Molecular structure, spectroscopic (FT-IR, FT-RAMAN), HOMO-LUMO, NMR,

and MEP analysis of methyl-m-toluate

 

I Sehar a, V Krishnakumarb and S Sivakumarc

aDepartment of Physics, Aditanar College of Arts and Science, Tiruchendur – 628 215, India

bDepartment of Physics, Periyar University, Salem - 636 011, India

cDepartment of Physics, Govt. Arts College, Salem - 636 007, India

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The FT-IR and FT-Raman spectra of methyl-m-toluate (MMT) molecule were recorded in the range 4000–400 cm-1 and 4000–100 cm-1, respectively at room temperature. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands were interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) method. The complete vibrational assignments of frequencies were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311+G** calculated results agreed well with the experimental values. The calculated HOMO and LUMO energies revealed that the charge transfer occurred within the molecule. Moreover, HOMO-LUMO energy gap related properties such as ionization potential, electron affinity, global hardness, global softness, chemical potential and electrophilicity index were calculated. The effects due to the substitution of methyl groups were also investigated. The calculated results from B3LYP/6-311+G** were applied to simulate the spectra of the title compound, which showed excellent agreement with the experimental spectra. Furthermore, Natural Bonding Orbital (NBO) analysis was done and stabilization energies E(2) were calculated. The change in electron density (ED) in the orbital and molecular electrostatic potential (MEP) were analyzed. © Anita Publications. All rights reserved.

Key words: FT-IR and FT-Raman spectra, MEP, HOMO-LUMO, DFT.

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Asian Journal of Physics                                                                                                               Vol 25, No 6, (2016) 00-00


Integration of phoneme pattern recognition with hidden Markov models to enhance

performance of low level speech recognition


Mohammed Al-Darkazali, Rupert Young, and Chris Chatwin, Phil Birch

School of Engineering and Informatics, 2B09, Shawcross building, Brighton BN1 9QT 43, U K

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The hidden Markov model (HMM) is commonly employed in automatic speech recognition (ASR). The HMM has been shown to have a good performance in many applications, although it has some well-known limitations in modelling speech. Therefore, the standard HMM topology has been modified in a variety of ways to reduce errors, including factorization of the HMM into multiple-streams. However, the gap between the theoretical representation of speech and its acoustic representation can be further reduced. This paper describes a new method of correcting the HMM based on matching two dimensional templates of word time-frequency patterns to assist in low level speech recognition (Pl correct sentence construction). This is shown to be a promising method to enhance speech recognition performance. © Anita Publications. All rights reserved.

Keywords: Pattern matching, image matching, hidden Markov models, automatic speech recognition.

Total Refs: 17

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