Prof. (Dr.) Debashis Gangopadhyay

Director - School of Sciences

PhD

Email: debashis.g@snuniv.ac.in khokag@gmail.com

Area of Research: Quantum Field Theory, Cosmology, Quantum Computation and Information

Employment / Education / Miscellaneous :?

• Faculty (1st March 2020 onwards) : Dept.Of Physics, Sister Nivedita University, Kolkata?

• Faculty ( 1st Jan 2012- 30th April 2020): Ramakrishna Mission Vivekananda Educational and Research Institute, Belur Matth, Howrah?

• Faculty (18th July 1991- 31st Dec. 2011): S. N. Bose National Centre for Basic Sciences, Kolkata, India?

• Postdoctoral Fellow (1989-1991): Bogolubov Laboratory of Theoretical Physics, Joint Institute of Nuclear Research, Dubna, Moscow, Russia?

• Postdoctoral Fellow (1987-1989): Institute of Physics, Bhubaneswar, India

• Lecturer in Physics (1986-1987): Head, Department of Physics, College of Textile Technology, Berhampore, Murshidabad, India

• Ph. D. (1988): Saha Institute of Nuclear Physics, Kolkata, India?

• M.Sc. (Physics,First Class)(1977): University of Calcutta, Kolkata, India?

• B.Sc. (Physics Hons.,First Class)(1975): Presidency College, University of Calcutta, Kolkata, India?

• Indian School Certificate (First Division) (1972), Calcutta Boys' School, University of Cambridge Local Examinations Syndicate

• National Scholarship (1972)?

• National Science Talent Search Scholarship (1972 – 1977)

Selected Publications

• From geometry to observation: gravitational waves and the Raychaudhuri equation, Sougata Bhunia, Anubhab Dutta, Debashis Gangopadhyay, Goutam Manna, Physics of the Dark Universe V50, 102089 (2025)

• Non-affine extensions of the Raychaudhuri equation in the K-essence framework, Samit Ganguly, Goutam Manna, Debashis Gangopadhyay, Eduardo Guendelman, Abhijit Bhattacharyya, Physics Letters B868 , 139622 (2025)

• NEC violation in f(R,T) gravity in the context of a non-canonical theory via modified Raychaudhuri equation,  Arijit Panda, Debashis Gangopadhyay, Goutam Manna ,Astroparticle Physics 165 , 103059 (2025) (available online https://doi.org/10.1016/j.astropartphys.2024.103059)

• Form Invariance of Raychaudhuri equation in the presence of Inflaton-type fields,

Arijit Panda, Debashis Gangopadhyay, Goutam Manna ,

Fortschr. Phys. 2024 ,  2400134 (2024)

• An Accelerated Universe with Negative Equation of state parameter in Inhomogeneous Cosmology with k-essence Scalar field,  Somnath Mukherjee and Debashis Gangopadhyay, Physics of the Dark Universe 32, 100800, (2021)

• F(R) Gravity with k-essence Scaling Relation and Cosmic Acceleration, Somnath Mukherjee and Debashis Gangopadhyay, ISSN 2688-8300 (Print) ISSN 2644-3368 (Online), JMSCM, 1, No.4, (2020)

• Three Flavoured neutrino oscillations and the Leggett Garg Inequality, Debashis Gangopadhyay and Animesh Sinha Roy, Euro.Phys. Jour. C 77, 260 (2017)

• Semiclassical treatment of k-essence effect on cosmic temperature, Abhijit Bandyopadhyay, Debashis Gangopadhyay and Arka Moulik, Gravitation and Cosmology 23, 184 (2017)

• The Leggett-Garg Inequality and Page-Wootters Mechanism, Debashis Gangopadhyay and Animesh Sinha Roy, Euro. Phys. Lett. 116, 40007 (2016)

• The Hawking temperature in the context of dark energy for Reissner-Nordstrom and Kerr background, G. Manna and Debashis Gangopadhyay, Euro. Phys. Jour. C 74, 2811 (2014)

• Probing the Leggett-Garg Inequality for Oscillating Neutral Kaons and Neutrinos, D. Gangopadhyay, D.Home, A.Sinha Roy , Phys.Rev. A88 022115 (2013)

• The Hawking temperature in the context of dark energy Debashis Gangopadhyay and Goutam Manna,Euro.Phys.Lett. 10049001 (2012)

• The k-essence scalar field in the context of Supernova Ia Observations, Abhijit Bandyopadhyay, Debashis Gangopadhyay , Arka Moulik, Eur. Phys. Jour. C 72, 1943, (2012)

• Estimating temperature fluctuations in the early Universe, Debashis Gangopadhyay, Gravitation and Cosmology 16, 231 (2010)

• Logarithm of the scale factor as a generalised coordinate in a lagrangian for dark matter and dark energy, Debashis Gangopadhyay and Somnath Mukherjee, Physics Letters B 665, 121 (2008)

• The CNOT quantum logic gate using q-deformed oscillators, Debashis Gangopadhyay, Int. Jour. Quant. Inform. 6, 471 (2008)

• Evolution of primordial black holes in Jordan-Brans-Dicke Cosmology- A.S. Majumdar, Debashis Gangopadhyay, L.P.Singh,  Monthly Notices of the Royal Astronomical Society  385  1467 (2008)

• Spacetime Dependent Lagrangians and Electrogravity Duality- Debashis Gangopadhyay, R.Bhattacharjee, L.P.Singh, Gravitation and Cosmology, 13  , 285  (2007)

• Quantum Logic Gates with q-Deformed Oscillators- Debashis Gangopadhyay & M.N. Sinha Roy,   Int. Jour. Quant. Inform.   4   297 (2006)   

• Growth Models and Models of Turbulence: A Stochastic Quantisation Perspective- H.S.Samanta, J.K.Bhattacharjee, Debashis Gangopadhyay, Phys. Lett. A353   113 (2006) 

• Vacuum expectation value of the Higgs Fieldand Dyon Charge Quantisation from Spacetime Dependent Lagrangians- R.Bhattacharyya and D.Gangopadhyay, Mod.Phys Lett . A18   1 (2003)

• Spacetime Dependent Lagrangians and Weak-Strong Duality : Sine-Gordon and Massive Thirring Models-  R.Bhattacharyya and D.Gangopadhyay,  Mod.Phys.Lett.  A17  729 (2002)

• Duality in Equations of Motion from Spacetime Dependent Lagrangians-  R. Bhattacharyya and D. Gangopadhyay,       Modern  Physics  Letters  A15  901 (2000)  

• Duality invariance of cosmological solutions with torsion, Debashis Gangopadhyay and S. Sengupta, Int. Jour. Mod. Phys. A 14, 4953 (1999)

• Van der Waerden’ sColouringTheorem andClassicalSpinSystems - R.Chaudhury, D.  Gangopadhyay   and  S. K. Paul,      Mod. Phys. Lett. B11   923 (1997)

• Interacting Fermions , Scaling and Possible Departure  From Fermi  Liquid  Behaviour-  R. Chaudhury and  D. Gangopadhyay,  Mod. Phys. Lett..  B9  1657 (1995)

• Quantum  Discrete  Gauge  Models  with  Bosonic  and  Fermionic  Degrees  of  Freedom - A.T. Filippov , D. Gangopadhyay      and  A. P. Isaev,  Int. Jour. Mod. Phys.  A7  2487 (1992) 

• Discrete  “Strings” and Gauge  Model of  Three  Confined  Relativistic  Particles -  A.T. Filippov , D. Gangopadhyay  and  A.P.    Isaev , Int. Jour. Mod. Phys. A7  3639 (1992) 

• On canonical q-transformations with two q-oscillators, Debashis Gangopadhyay, Mod. Phys. Lett. A 31, 2909 (1991)

•  A.T. Filippov,  D. Gangopadhyay and  A.P.Isaev,        Jour. Phys. A24  L63  (1991) 

• On the Harmonic Oscillator Realisation of q-Oscillators- D. Gangopadhyay and A.P. Isaev , JINR Rapid Comm.45   35 (1990)

• Gauge fixing for linearized gravity and antisymmetric tensor fields, Debashis Gangopadhyay, Int. Jour. Mod. Phys. A 5, 2145 (1990)

• Fujikawa-type formulation of gauged BRST symmetry for the free Bosonic string, Debashis Gangopadhyay and L. P. Singh, Phys. Rev. D (Rapid Comm.) 38, 2652 (1988)

• Functional Stochastic Quantisation Of Gauge Theories- A.Chatterjee and D. Gangopadhyay,  Jour.Phys.G13    L97 (1987)

•    Debashis  Gangopadhyay,   A.  Chatterjee   and P.  Mazumdar Jour.Phys.G12     L1 (1986) 

• Factorisation inLarge-NLimit of Lattice Gauge Theories Revisited-  A. Chatterjee and D. Gangopadhyay,  Pramana 21      385   (1983)                                  

Research Interests?I have worked in the formalism and applications of quantum field theory. In cosmology I am mostly interested in using field theoretic techniques to understand the early universe and the dark matter and and dark energy scenario. In quantum computation and information theory, my interest lies in quantum logic gates and quantum correlations.

PhD students:?

(1) Rajsekhar Bhattacharyya (Ph. D. Jadavpur University), Thesis title: “Studies on recent development in non-perturbative aspects of gauge theories” ( Quantum field Theory)?

(2) Goutam Manna (Ph. D. Calcutta University), Thesis title: “Some studies in emergent gravity and k-essence ” (Cosmology and Quantum field Theory)?

(3) Somnath Mukherjee (Ph. D. Jadavpur University), Thesis title: “Some studies on cosmic origins of dark matter and dark energy” (Cosmology)

(4) Oindrila Ganguly (Ph. D. Calcutta University), Thesis title: “Lorentz invariance violation: a study in the context of effective theories” (Quantum Field Theory)?

(5) Animesh Singha Roy (Ph. D. RKMVERI), Thesis title: “Neutral Kaon Oscillations, Neutrino Oscillations and the Page-Wootters Mechanism in the light of the Leggett-Garg Inequality” (Quantum Correlations)

Visiting Summer Internships?(Indian Academy of Sciences, Bangalore):

Mr. Praneet Pathak , IIESER, Mohali, May-July 2019;?

Mr. Mritunjay Tyagi, Delhi University, June- August 2019 ;?

Ms. Ashwini Nagaraj Shenoy (II BE) N.M.A.M. Institute of Technology, Udupi, May-July 2020 ;?

Mr. Gaurang Ramakant Kane (II BTech) Indian Institute of Technology, Guwahati, June-August 2020;

Swara Mishra , St. Stepen’s, New Delhi,  2023;

Sagarneel Ghosh , IIT KGP, 2024

Plus 20 other direct summer interns from other universities over the years