Angom D. K. Singh

Professor
Tel: +91 (79) 2631 4463;
Fax: +91 (79) 2630 1502
e-mail: angom AT prl.res.in

Research Interests

Current Research Interests

My research interests are on theoretical matters related to atoms. These span a wide range of very exciting and challenging research areas. Be it the nature of fundamental interactions or the physics of galaxies or phenomena in condensed matter physics or quantum chaos or precision time keeping, it is of immense value to know atoms to fine detail. It is interesting and amazing to study how atoms respond to external fields. Depending on the nature of the field and how it is applied, one can have a peek at the inner workings of an atom or collection of atoms. Some of the revelations could be far reaching and of fundamental importance. My current research interests are:

  • Parity and time reversal violation in atoms
  • Atomic Parity nonconservation
  • Quantum chaos and complexity in heavy atoms
  • Condensates of dilute atomic gases
  • Coupled-cluster based methods for atomic many-body calculations
  • QED effects in heavy atoms
  • Vortex dynamics in superfluids
  • Finite temperature effects in Bose-Einstein condensates

Future Research Interests

In the near future I shall continue to work on research projects related to the above topics. As long term undertaking, I have initiated research work on the following topics:

  • Quantum phase transitions
  • Quenching in quantum liquids
  • Quantum turbulence
  • Time-dependent relativistic coupled-cluster theory

Publications

  1. Arko Roy and D. Angom,
    Thermal suppression of phase separation in condensate mixtures,
    Phys. Rev. A 92, 011601(R) (2015). 5pp
  2. S. Chattopadhyay, B. K. Mani, and D. Angom,
    Triple excitations in perturbed relativistic coupled-cluster theory and electric dipole polarizability of group-IIB elements,
    Phys. Rev. A 91, 052504 (2015). 14pp
  3. K. Suthar, Arko Roy, and D. Angom,
    Fluctuation-driven topological transition of binary condensates in optical lattices ,
    Phys. Rev. A 91, 043615 (2015). 9pp
  4. Arko Roy, S. Gautam and D. Angom,
    Evolution of Goldstone mode in binary condensate mixtures,
    Eur. Phys. J. Special Topics 90, 571 (2015). 5pp
  5. Arko Roy, and D. Angom,
    Fluctuation- and interaction-induced instability of dark solitons in single and binary condensates,
    Phys. Rev. A 90, 023612 (2014). 9pp
  6. K. Suthar, Arko Roy, and D. Angom,
    Acoustic radiation from vortex-barrier interaction in atomic Bose-Einstein condensate,
    J. Phys. B 47, 135301 (2014). 10pp
  7. S. Chattopadhyay, B. K. Mani, and D. Angom
    Electric dipole polarizability of alkaline-earth-metal atoms from perturbed relativistic coupled-cluster theory with triples,
    Phys. Rev. A 89, 022506 (2014). 12pp
  8. Arko Roy, S. Gautam, and D. Angom
    Goldstone modes and bifurcations in phase-separated binary condensates at finite temperature,
    Phys. Rev. A 89, 013617 (2014). 7pp
  9. S. Gautam, K. Suthar, and D. Angom Vortex reconnections between coreless vortices in binary condensates,
    Ed by Amita Das and A. Surjalal Sharma, AIP Conf. Proc. 1582, 46 (2014). 9pp
  10. S. Chattopadhyay, B. K. Mani, and D. Angom,
    Electric dipole polarizabilities of doubly ionized alkaline-earth-metal ions from perturbed relativistic coupled-cluster theory,
    Phys. Rev. A 87, 062504 (2013). 9pp
  • Arko Roy and D. Angom,
    Thermal suppression of phase separation in condensate mixtures,
    Phys. Rev. A 92, 011601(R) (2015). 5pp
  • Arko Roy and D. Angom,
    Fluctuation- and interaction-induced instability of dark solitons in single and binary condensates,
    Phys. Rev. A 90, 023612 (2014). 9pp
  • Arko Roy, S. Gautam and D. Angom,
    Goldstone modes and bifurcations in phase-separated binary condensates at finite temperature ,
    Phys. Rev. A 89, 013617 (2014). 7pp
  • Arko Roy, S. Gautam and D. Angom,
    Evolution of Goldstone mode in binary condensate mixtures,
    Eur. Phys. J. Special Topics 224, 571 (2015). 5pp
  • S. Gautam, P. Muruganandam and D. Angom, Formation and stability of coreless vortex dipoles in phase-separated binary condensates, Phys. Lett. A 377, 378 (2013). 9pp
  • S. Gautam, P. Muruganandam and D. Angom, Coreless vortex dipoles and trapped droplets in phase-separated binary condensates, J. Phys. B 45, 055303 (2012). 8pp
  • S. Gautam and D. Angom, Phase separation of binary condensates in harmonic and lattice potentials, J. Phys. B 44, 025302 (2011). 11pp
  • S. Gautam and D. Angom, Rayleigh-Taylor instability in binary condensates, Phys. Rev. A 81, 053616 (2010). (5pp)
  • S. Gautam and D. Angom, Ground state geometry of binary condensates in axissymmetric traps, J. Phys. B. 43, 095302 (2010). (7pp)
  • K. Suthar, Arko Roy, and D. Angom, Fluctuation-driven topological transition of binary condensates in optical lattices, Phys. Rev. A 91, 043615 (2015). 9pp
  • S. Gautam, P. Muruganandam, and D. Angom, Position swapping and pinching in Bose-Fermi mixtures with two-color optical Feshbach resonances, Phys. Rev. A 83, 023605 (2011). 7pp
  • S. Gautam and D. Angom, Scattering length for fermionic alkali atoms, Eur. Phys. J. D 56, 173 (2010). (7pp)
  • S. Silotri, D. Angom, H. Mishra and A. Mishra, Pairing in spin polarized two-species fermionic mixtures with mass asymmetry, Eur. Phys. J. D 49, 383 (2008). (8pp)
  • K. Suthar, Arko Roy, and D. Angom, Acoustic radiation from vortex-barrier interaction in atomic Bose-Einstein condensate, J. Phys. B 47, 135301 (2014). 10pp
  • Shashi Prabhakar, R. P. Singh, S. Gautam and D. Angom, Annihilation of vortex dipoles in an oblate Bose-Einstein condensate, J. Phys. B. 46, 125302 (2013). (8pp)
  • S. Gautam, K. Suthar and D. Angom, Vortex reconnections between coreless vortices in binary condensates, Ed by Amita Das and A. Surjalal Sharma, AIP Conf. Proc. 1582, 46 (2014). 9pp
  • S. Gautam and D. Angom, Critical temperature for Bose-Einstein condensation in quartic potentials, Eur. Phys. J. D 46, 1436 (2008). (5pp)
  • Y. Takahashi, M. Fujimoto, T. Yabuzaki, Angom D. Singh, M. K. Samal and B. P. Das, Electric Dipole Moment of Atomic Ytterbium by Laser Cooling and Trapping, in Proceedings of CP Violation and its Origin, edited by K. Hagiwara(KEK Reports, Tsukuba, 1997).
  • M.S. Santhanam, Jayendra N. Bandyopadhyay, and D. Angom,
    Quantum spectrum as a time series
    Fluctuation measures, Phys. Rev. E 73, 015201(R) (4 pp).
  • D. Angom and V. K. B. Kota,
    Chaos and localization in wavefunction structures of complex atoms Nd, Pm and Sm,
    Phys. Rev. A 71, 042504 (2005). (14pp)
  • D. Angom, S. Ghosh and V. K. B. Kota,
    Strength functions, entropies and duality in weakly to strongly interacting fermionic systems,
    Phys. Rev. E 70, 016209 (2004). (11pp)
  • D. Angom and V. K. B. Kota,
    Signatures of two-body random matrix ensembles in Sm I,
    Phys. Rev. A 67, 052508 (2003). (4pp)
  • D. Budker, B. K. Sahoo, D. Angom and B. P. Das, An overview of some experimental and theoretical aspects of fundamental symmetry violations in atoms in Proceedings of IXth National Laser Symposium, Part II: Laser Applications, Edited by Editors : L. M. Gantayet, et al.Pramana 75, 1041 (2010).
  • Dilip Angom, Kaushik Bhattacharya, Saurabh D. Rindani, Decay of Spin-One Particle into Two Photons in Presence of Uniform External Magnetic Field, arXive:hep-ph/0601168 (14pp); Int. J. Mod. Phys. A 22, 707 (2007).
  • Angom D. Singh, B. P. Das, The Parity Non-Conserving 3P0--1P1 E1 Transition Amplitude of the Atomic Yb, arXive:physics/0201010 (6pp).
  • Angom D. Singh and B. P. Das, Parity Non-Conservation in Atomic Yb Arising from the Nuclear Anapole Moment, J. Phys. B 32, 4905-4917 (1999).
  • K. P. Geetha, Angom D. Singh, B. P. Das and C. S. Unnikrishnan, Nuclear Spin-Dependent Parity-Nonconserving Transitions in Ba+ and Ra+, Phys. Rev. A 58, R16-R19 (1998).
  • Angom D. Singh, K. P. Geetha and B. P. Das, New Directions in Atomic Parity Violation, 95, Proc. of International Conference on Physics Since Parity Symmetry Breaking, Edited by Fan Wang (World Scientific, 1998).
  • S. Malhotra, Angom D. Singh, and B. P. Das, A Relativistic Configuration Interaction Analysis of Parity Non-Conservation in BaII, Phys. Rev. A 51, R2665-R2667 (1995).
  • Swati Malhotra, Angom D. Singh and B. P. Das, Parity Non-Conservation in BaII: A Theoretical Analysis of Contributions from Neutral Weak Currents and Nuclear Anapole Moment, 520, Proc. of International Conference on Non-Accelerator Particle Physics, Edited R. Cowsik (1995).
  • K. V. Latha, D. Angom, B. P. Das, and D. Mukherjee, Probing CP violation with electric dipole moment of atomic Mercury, Phys. Rev. Lett. 103, 083001 (2009).
  • K. V. Latha, D. Angom, B. P. Das, R. K. Chaudhuri and B. P. Das, Core polarization in coupled-cluster theory induced by a parity and time-reversal violating interaction, J. Phys. B 41, 035005 (2008).
  • K. V. P. Latha, D. Angom, R. K. Chaudhuri, B P Das and D. Mukherjee, A new formulation of the relativistic many-body theory of electric dipole moments of closed shell atoms, J. Phys.: Conf. Ser. 80, 012049 (2007).
  • Angom D. singh, Bhanu Pratap Das, M. K. Samal and Warren F. Perger, Many-Body Theory of the Electric Dipole Moment of the Atomic Ytterbium, J. Phys. B 34, 3089-3106(2001).
  • Angom D. Singh, B. P. Das, D. Mukherjee, Coupled Electron Pair Approximation Calculation of the Electric Dipole Moment of Atomic Yb, arXive:physics/0111165 (19pp).
  • S. Chattopadhyay, B. K. Mani, and D. Angom, Triple excitations in perturbed relativistic coupled-cluster theory and electric dipole polarizability of group-IIB elements, Phys. Rev. A 91, 052504 (2015). 14pp
  • S. Chattopadhyay, B. K. Mani, and D. Angom, Electric dipole polarizability of alkaline-earth-metal atoms from perturbed relativistic coupled-cluster theory with triples, Phys. Rev. A 89, 022506 (2014). 12pp
  • S. Chattopadhyay, B. K. Mani, and D. Angom, Electric dipole polarizabilities of doubly ionized alkaline-metal ions from perturbed relativistic coupled-cluster theory, Phys. Rev. A 87, 062504 (2013). 9pp
  • S. Chattopadhyay, B. K. Mani, and D. Angom, Electric dipole polarizabilities of alkali-metal ions from perturbed relativistic coupled-cluster theory Phys. Rev. A 87, 042520 (2013). 8pp
  • Alok K. Singh, D. Angom and Vasant Natarajan, Perturbed Observation of the nuclear magnetic octupole moment of 173Yb From presicse measurement of the hyperfine structure in 3P2 state, Phys. Rev. A 87, 012512 (2013). 5pp
  • S. Chattopadhyay, B. K. Mani, and D. Angom, Perturbed coupled-cluster theory to calculate dipole polarizabilities of closed-shell systems: Application to Ar, Kr, Xe, and Rn Phys. Rev. A 86, 062508 (2012). 12pp
  • S. Chattopadhyay, B. K. Mani and D. Angom Electric fipole polarizability from perturbed relativistic coupled-cluster theory: application to neon, Phys. Rev. A 86, 022522 (2012). 6 pp
  • B. K. Mani and D. Angom Fock-space relativistic coupled-cluster calculations of two-valence atoms, Phys. Rev. A 83, 012501 (2011). 21 pp
  • B. K. Mani, and D. Angom Atomic properties calculated by relativistic coupled-cluster theory without truncation: hyperfine constants of Mg+, Ca+, Sr+, and Ba+, Phys. Rev. A 81, 042514 (2010). 11pp
  • B. K. Mani, K. V. P. Latha, and D. Angom Relativistic coupled-cluster calculations 20Ne, 40Ar, 84Kr and 129Xe: correlation energies and dipole polarizabilities, Phys. Rev. A 80, 062505 (2009). (10pp)
  • S. Fritzsche, Brajesh K. Mani and D. Angom A Computer-Algebraic Approach to the Derivation of Feynman–Goldstone Perturbation Expansions for Open-Shell Atoms and Molecules, Adv. Quan. Chem. 53, 177-215 (2008).
  • T. Kondo, D. Angom, I. Endo, A. Fukumi, T. Horiguchi, M. Iinuma and T. Takahashi, Stark Spectroscopy of High-Lying Odd Parity Levels in Atomic Samarium, Eur. Phys. J. D 25, 103-111 ( 2003).
  • A. Fukumi, D. Angom, I. Endo, T. Horiguchi, M. Iinuma, T. Kondo and T. Takahashi, Observation of Stark-Induced Electric Dipole Transition in Atomic Samarium with Optical Double Resonance, J. Phys. Soc. Japan 71, 2137(2002).
  • D. Angom, I. Endo, A. Fukumi, M. Iinuma, T. Kondo and T. Takahashi, The Multi-Configuration Dirac-Fock Calculation of the Low-lying Levels of Sm, Eur. Phys. J. D 14, 271-277(2001).

Research

discrete symmetry violations in atoms

Results from the studies of discrete symmetry violations in atoms, molecules and solid state systems have important implications to fundamental physics. Currently, there are experiments in several labs to measure the effects of P violation, P and T violation, and CPT nonconservation. To mention a few, our collaborator Dmitry Budker and coworkers are measuring the parity nonconservation effects in atomic Yb and P and T violation in solids. Fortson and coworkers measured EDM, the signature of P and T violation to high precision in atomic Hg. Mike Romalis and his group conducts experiments to detect CP and CPT violations.

ultracold atom clouds

The Bose-Einstein condesate (BEC) of the bosonic cold atoms is an interesting state of matter. The importance and impact of which can be far reaching as lasers. The BEC of cold atoms was first observed by Wieman and Cornell, Ketterle, and Hulet. Among whom Cornell, Ketterle and Wieman were awarded the Nobel Prize in 2001 for their work on BEC of alkali atoms. Subsequently BEC of alkali atoms in fine detail. In a recent work, our collaborator Yoshiro Takahashi has observed BEC in atomic Yb. The ultracold fermionic atoms are important to understand BCS state in finer detail. Fermionic alkali atoms were first cooled to degeneracy by Jin. After several experiments, Ketterle first observed BCS pairing without ambiguity

atomic many body theory

Finding new laser transitions, atomic clock transitions, precision spectroscopy, etc of atoms require accurate atomic structure and properties calculations. Out of all the atoms listed in the periodic table only Hydrogen atom is exactly solvable, which is also one of the few realistic exactly solvable quantum systems. The calculations become complicated and challenging for heavy atoms, which have to be done relativistically. We use a variety of many-body methods, coupled-cluster or related methods are the ones we use. These are considered the best methods. In these endeavours we collaborate with Debashis Mukherjee, one of the leading experts of coupled-cluster method.

quantum many-body chaos

Quantum many body systems like nuclei, atoms, molecules, etc. exhibit very complex properties. In these systems it is near impossible to do spectroscopic studies of the highly excited states. A possible way out of this difficult situation is to use statistical methods. Random matrix methods provide a way to study the physics of highly excited states and make predictions. The embedded random matrix ensembles have found wide applications in the studies of quantum many body systems. V. K B. Kota and collaborators have studied this class of random matrix ensembles. In recent times we have used one type of this class in atoms with interesting results.

quantum chaos

Chaos in simple quantum systems like anharmonic oscillators, kicked top, kicked rotor, etc. is inferred from the agreement of the statistical measures with that of random matrix ensembles. An interesting system of study is coupled quartic oscillators.

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Contact

Address : Theoretical Physics Division
Physical Research Laboratory,
Navrangpura,
Ahmedabad 380009, India.
Office Phone : +91 (79) 2631 4463;
Fax : +91 (79) 2630 1502
Email ID : angom@prl.res.in
Web Page : https://www.prl.res.in/~angom
Mobile No :