My email address :-
gautam@boson.bose.res.in
under construction
Name: GAUTAM GANGOPADHYAY
e-mail:gautam@boson.bose.res.in FAX: (91) (33) 2335 3477
Present Status:
Working as an Associate Professor at the S N Bose National Centre
for Basic Sciences (SNBNCBS), Salt Lake City, Kolkata-98.
Research Experience:
i. Radiation matter interaction; linear and nonlinear
spectroscopy; quantum optics.
ii. Activated barrier crossing problems; Reaction Rate
theory; Ultrafast spectroscopy and Reaction Rates of Molecular system.
iii. Complex Dynamics of Chemical and Biological Systems.
List of Publications
1. A global stochasticity criteria for Maxwell-Bloch equation,
G Gangopadhyay and D S Ray, Phys. Rev. A 40 (1989) 3750
2. Spectra of four-wave mixing in a self-consistent field,
G Gangopadhyay and D S Ray, Phys. Rev. A 41 (1990) 3985
3 Power spectra of light scattered from a strongly driven
Morse oscillator,
G Gangopadhyay and D S Ray, Phys. Rev. A 41 (1990) 6429
4. Quantum electrodynamics of a single Morse oscillator
in a cavity; spectral aspects,
G Gangopadhyay and D S Ray, Phys. Rev. A 43 (1991) 6424
5. Master equation for dissipative dynamics of a two-level
atom in a superintense field; field dependent relaxation,
G Gangopadhyay and D S Ray, Phys. Rev. A 44 (1991) 2206
6. Spectral modification of the Stokes line of a Raman-coupled
three level system in a cavity,
G Gangopadhyay and D S Ray, Phys. Rev. A 45 (1992) 1843
7. Cavity QED with a single Morse oscillator, G Gangopadhyay and D S Ray, in Quantum Optics edited by R Inguva (PlenumPress, N. Y. 1992)
8. Master equation for nonlinear dissipative systems, G Gangopadhyay and D S Ray, J. Chem. Phys. 96 (1992) 4693
9. A master equation approach to multiphoton dissociation
of Morse oscillator,
G Gangopadhyay and D S Ray, J. Chem. Phys. 97 (1992)
4104
10. Non-Markovian master equation for linear and nonlinear
systems,
G Gangopadhyay and D S Ray, Phys. Rev. A 46 (1992) 1507
11. Cavity field-assisted atomic relaxation and suppression
of resonance fluorescence at high intensities,
G Gangopadhyay, S Basu and
D S Ray, Phys. Rev. A 47 (1993) 1314
12. A fluctuation-diffusion relation in chaotic dynamics,
S Chaudhuri,G Gangopadhyay and D S Ray, Phys.Rev.E 47 (1993)311
13. Population trapping in a Raman-coupled model interacting with a two-mode quantized cavity fields, B Deb, G Gangopadhyay and D S Ray, Phys. Rev. A 48 (1993) 1400.
14. Master equation in quantum optics; some generalizations, G Gangopadhyay and D S Ray, in Advances in Multiphoton Processes, edited by S H Lin, A A Villaeys and F Fujimura, World Scientific, Singapur, 1993.
15. Coherent phase state and displaced phase state in
a finite dimensional basis and their light field limits,
G Gangopadhyay,
J. Mod. Opt. Vol 41 (1994) 525.
16. Generation of a class of arbitrary two-mode field state in a cavity, B. Deb, G Gangopadhyay and D.S. Ray, Phys. Rev. A 51 (1995) 2651.
17. Fluctuation and decoherence in classical chaos: A model study of a Kubo oscillator generated by a chaotic system, S Chaudhuri, G Gangopadhyay and D S Ray, Phys. Rev. E52 (1995) 2262.
18. Population trapping in the Jaynes-Cummings model with
a kerr nonlinear medium,
A Bandyopadhyay and G Gangopadhyay , J. Mod. Opt.
43 (1996) 487.
19. The non-Markovian master equation for stochastically perturbed systems; effect on spectral lineshape, G Gangopadhyay and D S Ray, J. Mol. Struc.(Theo Chem), 361 (1996) 49.
20. Signature of Classical chaos on field induced quantum barrier crossing, S Chaudhuri, G Gangopadhyay and D S Ray, Special issue on Complex systems, Indian Journal of Physics, 69B (1995)507.
21. Field induced quantum barrier crossing; classical chaos and weak localization, S Chaudhuri, G Gangopadhyay and D S Ray, Phys.Letts. A216 (1996) 53.
22. Theory of Quantum fluctuations in classically chaotic Hamiltonian systems, S Chaudhuri, G Gangopadhyay and D S Ray, Phys. Rev E54 (1996)53
23. The effect of environment induced pure dephasing in
the Jaynes-Cummings model,
G Gangopadhyay and S H Lin, Physica Scripta
55 (1997) 425.
24. The effect of environment induced pure dephasing in
the generalized Jaynes-Cummings model,
G Gangopadhyay and S H Lin, Pramana-
J. Phys. 49 (1997) 399.
25. A thermal bath induced Rabi splitting on the profile
of Mollow spectrum in single molecule spectroscopy,
G Gangopadhyay and
S Ghoshal Chem. Phys. Letts 289 (1998) 287.
26. Absorption line shape of impurity molecule driven
by a fractal noise,
G Gangopadhyay and Y Tanimura, Chem. Phys. Letts. 289
(1998) 97.
27. Quantum Theory of dissipation of a harmonic oscillator coupled to a non-equilibrium bath; Wigner-Weisskopf decay and Physical Spectra, J Ray Chaudhuri, B Deb, G Gangopadhyay and D S Ray, J. Phys. B 31 (1998) 3859.
28. Theory of non-stationary activated rate processes: non-exponential kinetics, J Ray Chaudhuri, G Gangopadhyay and D S Ray, J. Chem. Phys 109 (1998) 5565.
29. A generating function for the product of Laguerre
polynomials: Franck-Condon factor for multiphoton processes,
G Gangopadhyay,
J. Phys. A Math. & Gen. 31 (1998) L771.
30. A thermal bath induced new resonances in linear and
nonlinear spectra of a two-level system,
G Gangopadhyay, S Ghoshal and
Y Tanimura, Chem. Phys. 242 (1999) 367.
31. An operator approach to the construction of generating
function for the product of Laguerre Polynomials: A thermal average bandshape
function of a molecule,
G Gangopadhyay, J. Phys. A Math. & Gen. 32
(1999) L441.
32. Steady state spectral properties of dendrimer supermolecules
as light harvesting system,
D. Rana and G. Gangopadhyay, Chem. Phys. Letts. 314 (2001)
324.
33. On dissipationless decoherence ,
G. Gangopadhyay, M. Sanjay Kumar and S. Dattagupta, J.
Phys. A 34 (2001) 5485.
34. Spectra of displaced distorted oscillator molecular
system ,
S. Banerjee and G. Gangopadhyay, Chem. Phys. Letts.
359 (2002) 295.
35. Studies on energy transfer
in Dendrimer supermolecule using classical random walk model and Eyring model,
D. Rana and G. Gangopadhyay, J. Chem. Phys.
118 (2003) 434.
36. Power law relaxation kinetics in multistate reversible
reaction,
S. Paul and G. Gangopadhyay, Chem. Phys. Letts.
369 (2003) 643.
37. Power law relaxation kinetics in reversible
enzyme-catalyzed reaction due to diffusion,
S. Paul and G. Gangopadhyay, J. Chem. Phys. 119(2003) 3501.
38. Quantum beat in pump-probe signal of molecular system,
S. Banerjee and G. Gangopadhyay, J. Phys. B 36 (2003) 2967.
39.
Dynamics of cascade three level system interacting with the classical
and quantized field,
40. Born-Oppenheimer approximation: A Toy version,
41. Radiative Decay of Nonstationary System ,
42. The absorption bandshape function of a molecule from a thermocoherent state and some associated multilinear generating-function relationships for Laguerre polynomials,
43. Laser cooling of vibrational degrees of freedom of a molecular system,
44. Theoretical studies of electron transfer through dendrimer architecture,
45. On the quantum theory of electron transfer: effect of potential surfaces of the
reactant and product,
46. On the microscopic basis of Newton's law of cooling and beyond,
47. Quantum electron transfer processes induced by thermocoherent state,
48. Effect of field quantization on Rabi oscillation of equidistant cascade four-level system,
49. Dynamical symmetry breaking of lambda and vee-type three-level systems
on quantization of the field modes,
50. Spectra of conjugated polymer aggregates: Symmetry of the interchain dressed states,
51. Aggregate of a network of conjugated polymer chains: Symmetry of the excitonic states and spectral features,
52. Effect of geometry of dipolar orientations on the spectra of di and trimer chain aggregates.
53. Master equation approach to single oligomeric enzyme catalysis: Mechanically controlled further catalysis,
54. Role of positional disorder in the spectra of conjugated polymer
aggregates: conical intersection of potential energy surfaces
55. Bloch equation and atom-field entanglement scenario in three-level systems,
56. Magnetically induced variation of tunneling current and nonclassicality in a coupled quantum dot system,
57. Bloch space structure, the qutrit wave function and atom-field entanglement in three-level systems,
58. Stochastic theory of interfacial enzyme kinetics: A kinetic Monte Carlo study,
59. Electronic nuclear entanglement in a conjugated polymer aggregate with a conical intersection: spectral signatures
60. Decoherence without dissipation due to fermionic bath,
61. Entropic estimate of cooperative binding of substrate on a single oligomeric enzyme: An index of cooperativity,
62. Entropy hysteresis and nonequilibrium thermodynamic efficiency of ion conduction in a voltage-gated potassium ion-channel,
63. Entropy production of a mechanically driven single oligomeric enzyme: a consequence of fluctuation theorem,
64. On the estimation of cooperativity in ion channel kinetics: activation free energy and kinetic mechanism of potassium ion channel,
Some recent research activities(2008-2012):
i. Quantum characterization of luminescence of conjugated polymer aggregates:
We have studied on the characterization of luminescence properties of aggregates of polymeric chains in terms of the nonadiabatic molecular processes. The key ingredient is the fact that the potential energy surfaces of different electronic states are not mutually independent and thus gives rise to strange excited state static and dynamic properties.We have theoretically studied the nature of symmetry of the interchain excitonic states for a network of conjugated polymer aggregate system consisting of N equivalent polymer chains. For equivalent tetramer aggregates with square planar (2D) and tetrahedral (3D) structures, permutation symmetry approach is an appropriate general recipe to classify the symmetry of the eigenstates of both the tetramer systems. The absorption and emission spectra for different classes of aggregates, over a wide range of temperatures, are explained in terms of the symmetry properties of the coupled excitonic states. We have also studied the effect of geometry of dipolar orientations on the spectra of dimer and trimer chain aggregates in a different context. Using the dimer model we have explained the basic features of Lamellar and herringbone aggregate spectra. We have also explained the blue shift in absorption for the cyclic trimer compared to its linear counterpart for comparable interchain interactions for thiophene aggregates which was discussed earlier through Frenkel exciton theory with only electronic degrees of freedom.
M R Nath,S Sen and G Gangopadhyay, Pramana-J. Phys. 61 (2003) 1089-1100.
G Gangopadhyay and B. Dutta-Roy, Am. J. Phys. 72 (2004) 389.
S. Banerjee and G. Gangopadhyay, J. Chem. Phys. 120 (2004) 6152.
H. M. Srivastava and G. Gangopadhyay, Russ. J. Math. Phys. 11 (2004) 359-367.
S. Banerjee and G. Gangopadhyay, J. Chem. Phys. 123 (2005) 114304.
D. Rana and G. Gangopadhyay, J. Chem. Phys. 124 (2006) 044909.
S. Banerjee and G. Gangopadhyay, J. Chem. Phys. 126 (2007) 034102.
M R Nath, S Sen and G. Gangopadhyay, J. Chem. Phys. 127 (2007) 094505.
S. Banerjee and G. Gangopadhyay, J. Chem. Sciences 119 (2007) 1-10.
M R Nath, T K Dey, S Sen and G. Gangopadhyay,, Pramana- J. Phys.70 (2008) 141.
M R Nath, S Sen, A K Sen and G. Gangopadhyay,, Pramana- J. Phys.71 (2008)77.
K. Banerjee and G. Gangopadhyay, J. Chem. Phys. 130 (2009) 084705.
K. Banerjee and G. Gangopadhyay, J. Phys.B 42 (2009) 165106.
K. Banerjee and G. Gangopadhyay, Phys. Rev. B 81 (2010) 035307.
B. Das and G. Gangopadhyay, J. Chem. Phys. 132 (2010) 135102.
K. Banerjee and G. Gangopadhyay, J. Phys.B 43 (2010) 235104.
S. Sen, M. R. Nath, T. K. dey and G. Gangopadhyay, AIP Conf. Proc. 1384 (2011) 190.
K. Banerjee and G. Gangopadhyay, AIP Conf. Proc. 1384 (2011) 137.
S. Sen, M. R. Nath, T. K. dey and G. Gangopadhyay, Annals of Physics 327 (2012) 224.
B. Das and G. Gangopadhyay, Chem. Phys. 393 (2012) 58.
K. Banerjee and G. Gangopadhyay, J. Phys.B 45 (2012) 045102.
A. Karmakar and G. Gangopadhyay, Physica Scripta 85 (2012) 045008.
K. Banerjee, B. Das and G. Gangopadhyay, J. Chem. Phys. 136 (2012) 154502.
B. Das, K. Banerjee and G. Gangopadhyay,
Phys. Rev. E 86, (2012) 061915.
B. Das, K. Banerjee and G. Gangopadhyay, J. Math. Chem.51, (2013) 588.
K Banerjee, B Das and G Gangopadhyay, J. Chem. Phys. (in Press).
ii. Stochastic theory of chemical reaction kinetics at the single molecule level:
Motivated by the single molecule enzymatic experiments we have provided a master equation description of enzyme catalysis in a chemiostatic condition for an immobilized oligomeric molecule with many equivalent active sites. The random attachment and detachment of substrate molecules on the various active sites of the oligomeric enzyme is studied in terms of the classical parameters of the Michaelis-Menten type process. In the limit of single molecule process, the master equation approach gives the result of waiting time distribution. On the other hand, for a large number of equivalent active sites or a few number of active sites with large Michaelis constant the master equation gives a Poisson distribution in the nonequilibrium steady state. For the oligomeric enzyme, the net rate of the reaction in the nonequilibrium steady state is multiplied by the number of active sites which is further enhanced by more than two orders of magnitude with the application of external force of 10-100pN through the techniques of atomic force microscopy. Substrate flux and reaction rate constants have interesting consequences on the dynamics and at nonequilibrium steady state which can be the controlling factors for macroscopic biochemical processes. In the spirit of Gillespie's stochastic approach we have provided a stochastic simulation technique for the study of interfacial enzyme kinetics where deltailed kinetic steps are considered on the basis of a recent expeiment through wide field fluorescence microscopy. Here we have given a microscopic description of hopping and scooting mode motion at the single enzyme level to find the dependence of the macroscopic rate in the long time limit and the lag-burst phenomenon at early time dynamics. Hopping over the fluid and product region involves diffusion in two widely separated time scales and thereby a dynamic disorder is developed in the turnover time which discriminates from the scooting mode motion of the enzyme in the burst phase of kinetics. We have provided a master equation approach
to study kinetics and nonequilibrium thermodynamics of single potassium ion channel. Recently we are working on the cooperativity
of ligand binding and ion channel problems from the trajectory entropy estimation. This simulation technique can also be applicable to understand other complex biological activities where various mechano and electro chemical rate processes are involved.