Research Themes & Research Inquiries
Santanu Pradhan is a PhD Researcher in Physics at IIT Kanpur. His current experimental work in buffer-gas physics examines atomic coherence and diffusion in thermal vapor cells. His earlier research explored black-hole perturbations, quasinormal modes, and tidal Love numbers in modified gravity. Optical magnetometry, cold atoms, graphene optomechanics, and quantum information are future research directions.
Buffer Gas Physics (Current Experimental Project)
Within the Quantum Measurement Lab at IIT Kanpur, I am currently conducting an experimental project investigating buffer-gas physics in thermal alkali vapor cells. The project focuses on characterizing atomic diffusion, spin-relaxation reduction, and collisional decoherence suppression to optimize quantum coherence times and optical pumping efficiency. This initial project establishes the experimental foundation for upcoming research in optical magnetometry, cold atoms, graphene optomechanics, and quantum information theory.
5-stage research roadmap:
Questions Guiding My Work
- 1.How do collisional dynamics between alkali atoms (e.g. Rb/Cs) and inert buffer gases (such as N2, He, or Ne) suppress spin-relaxation on vapor cell walls?
- 2.How does atomic spatial diffusion in a buffer gas environment influence optical pumping rates and quantum memory storage lifetimes?
- 3.What are the optimal temperature and pressure regimes for maximizing spin-coherence in precision atomic vapor cells?
- 4.How can theoretical transport models and experimental absorption/fluorescence spectroscopy be combined to quantitatively characterize the system?
Academic & Research Trajectory
Undergraduate Foundations
Ramakrishna Mission Residential College, University of Calcutta
First Class Honours in BSc Physics; researched Green's functions and their applications in solving differential equations of mathematical physics.
MSc Research & Computational Methods
IIT Indore
Master's thesis under Prof. Manavendra Mahato on AdS/CFT duality, anti-de Sitter black-hole thermodynamics, Unruh radiation, and an alternative numerical method for Kerr black-hole quasinormal modes.
Earlier Doctoral Research (Gravitation)
IIT Kanpur
Initial doctoral research under Prof. Tapobrata Sarkar exploring Fermi normal coordinates, tidal forces, and surface-regularized white-dwarf tidal Love numbers in EiBI gravity (manuscript in preparation).
Quantum Measurement Lab (Buffer Gas Physics Project)
IIT Kanpur
Joined the Quantum Measurement Lab under Prof. Saikat Ghosh to execute an experimental buffer-gas physics project as the foundation for research in optical magnetometry, cold atoms, graphene optomechanics, and quantum information.
Thematic Focus Areas
Buffer Gas Physics (Current Project)
Experimental vapor cell dynamics & coherence preservation
Investigating collisional decoherence suppression, atomic spatial diffusion, and spin-polarization lifetimes in thermal alkali vapor cells through experimental spectroscopy and numerical transport modeling.
Key Problems Under Study:
- ?How do inert buffer gases suppress wall-collision spin depolarization?
- ?How does spatial diffusion govern optical pumping and quantum memory storage times?
- ?What are the optimal gas pressure and temperature parameters for atomic coherence?
Methodological Frameworks:
Optical Magnetometry & Quantum Sensing
Upcoming doctoral research in precision atomic sensing
Developing atomic vapor magnetometers operating in the Spin-Exchange Relaxation-Free (SERF) regime and exploring quantum noise limits for field-deployable magnetic sensors under India's National Quantum Mission.
Key Problems Under Study:
- ?How can spin-exchange relaxation be eliminated at high atomic densities in zero-field environments?
- ?What are the fundamental limits of magnetic sensitivity imposed by photon shot noise and spin projection noise?
Methodological Frameworks:
Laser-Cooled Cold Atoms & Optical Trapping
Upcoming doctoral direction in ultra-cold atomic ensembles
Investigating laser-cooled atoms in Magneto-Optical Traps (MOTs), structured optical tweezers, atom-light interactions, and spin-fluctuation spectroscopy in coherently driven cold atomic ensembles.
Key Problems Under Study:
- ?How can structured optical tweezers control single-atom and ensemble quantum states?
- ?What mechanisms govern spin-fluctuations in coherently driven laser-cooled atoms?
Methodological Frameworks:
Graphene & 2D Quantum Optomechanics
Upcoming research in hybrid nano-mechanical resonators
Exploring mechanical and optomechanical properties of graphene/SiNx hybrid resonators as quantum-limited motion transducers, non-linear amplifiers, and platforms for non-equilibrium steady states.
Key Problems Under Study:
- ?How does optomechanical coupling in 2D hybrid resonators enable quantum-limited motion sensing?
- ?What non-linear dynamical phases emerge in driven graphene mechanical membranes?
Methodological Frameworks:
Quantum Information Theory & Weak Measurements
Upcoming direction in precision quantum metrology
Applying weak measurement protocols (Aharonov-Albert-Vaidman weak values), quantum state estimation, and quantum tomography to explore fundamental measurement limits and amplification.
Key Problems Under Study:
- ?How can weak value amplification enhance the measurement of ultra-small physical parameters?
- ?How can quantum coherence in atomic ensembles be optimally characterized and preserved?
Methodological Frameworks:
Gravitation, Black Holes & Compact Objects
Earlier doctoral and master's research foundations
Exploration of general relativity, Fermi normal coordinates, tidal forces in black-hole spacetimes, and surface-regularized tidal Love numbers of white dwarfs in Eddington-inspired Born-Infeld (EiBI) modified gravity.
Key Problems Under Study:
- ?How do Fermi normal coordinates and local inertial frames characterize tidal forces in black-hole geometries?
- ?How does Eddington-inspired Born-Infeld gravity affect the tidal deformability of white dwarfs?
Methodological Frameworks:
Computational Physics & Numerical Methods
Cross-cutting methodological stack
Developing and utilizing numerical differential equation solvers, scientific programming (Python, MATLAB, C++), Mathematica symbolic calculus, and data analysis pipelines across atomic and gravitational physics.
Key Problems Under Study:
- ?How can numerical algorithms be optimized for stability and accuracy in stiff boundary-value problems?
- ?How can computational models bridge theoretical physics with experimental spectroscopic data?
Methodological Frameworks:
Research project archive
Buffer Gas Physics & Atomic Vapor Coherence
Current Doctoral Experimental Project — Quantum Measurement Lab — Role: PhD Researcher
Conducting an experimental project investigating buffer-gas dynamics in thermal alkali vapor cells. The work focuses on analyzing collisional decoherence suppression, spatial diffusion rates, and optical pumping optimization to prolong atomic spin-coherence lifetimes.
Supervisor: Prof. Saikat Ghosh
Optical Magnetometry & SERF Quantum Sensing
Upcoming Doctoral Direction — Quantum Measurement Lab — Role: PhD Researcher
Upcoming research on optically pumped atomic magnetometers operating in the Spin-Exchange Relaxation-Free (SERF) regime for ultra-sensitive, field-deployable magnetic field detection under India's National Quantum Mission.
Supervisor: Prof. Saikat Ghosh
Laser-Cooled Cold Atoms & Optical Trapping
Upcoming Doctoral Direction — Quantum Measurement Lab — Role: PhD Researcher
Upcoming research into laser-cooled atomic ensembles in Magneto-Optical Traps (MOTs) and structured optical tweezers to study atom-light interactions, dual-species co-trapping, and spin-fluctuation spectroscopy.
Supervisor: Prof. Saikat Ghosh
Graphene & 2D Quantum Optomechanics
Upcoming Doctoral Direction — Quantum Measurement Lab — Role: PhD Researcher
Upcoming research exploring the mechanical and optomechanical properties of graphene/SiNx hybrid resonators as quantum-limited motion transducers, non-linear amplifiers, and non-equilibrium steady states.
Supervisor: Prof. Saikat Ghosh
Quantum Information Theory & Weak Value Measurements
Upcoming Doctoral Direction — Quantum Measurement Lab — Role: PhD Researcher
Upcoming theoretical and experimental investigations applying weak measurement protocols (Aharonov-Albert-Vaidman weak values), quantum state estimation, and quantum tomography to explore fundamental precision limits.
Supervisor: Prof. Saikat Ghosh
Surface Regularized Tidal Love Numbers of White Dwarfs in Eddington-Inspired Born-Infeld Gravity
Previous Doctoral Research Project — Manuscript in Preparation — Role: PhD Researcher
Investigated the tidal deformability and surface-regularized tidal Love numbers of white dwarf stars in Eddington-inspired Born-Infeld (EiBI) gravity, analyzing modified gravity constraints on compact objects.
Former supervisor: Prof. Tapobrata Sarkar
Fermi Normal Coordinates and Tidal Forces in Black-Hole Spacetimes
Previous Doctoral Research Project — Role: PhD Researcher
Studied the construction of Fermi normal coordinates, local inertial frames, geodesic deviation, and tidal force dynamics in the vicinity of black-hole spacetimes.
Former supervisor: Prof. Tapobrata Sarkar
AdS/CFT Introduction & Properties of Anti-de Sitter Black Holes: Quasi Normal Mode Calculation in Various Black Hole Models
MSc Thesis in Physics — Role: Master's Thesis Researcher
Comprehensive Master's dissertation investigating the AdS/CFT correspondence, thermodynamic properties of anti-de Sitter black holes, and numerical computation of quasinormal modes across diverse black-hole geometries.
Supervisor: Prof. Manavendra Mahato
Quasi Normal Modes Calculation of Kerr Black Holes
Alternative Numerical Formulation — Master's Research Project — Role: Master's Researcher
Developed a novel alternative computational method to calculate the Quasi Normal Modes (QNMs) of rotating Kerr black holes. The newly formulated method is numerically and computationally efficient, simple, and less time-consuming, matching benchmark results (such as Leaver's continued fraction method) with extraordinary precision up to 10 decimal places.
Supervisor: Prof. Manavendra Mahato
Unruh Radiation
Seminar Project in Quantum Field Theory in Curved Spacetime — Role: Seminar Researcher
A theoretical study of the Unruh effect, examining how accelerating observers in Minkowski spacetime perceive the vacuum state as a thermal bath, connecting acceleration with particle perception.
Supervisor: Prof. Manavendra Mahato
Minimal Supersymmetric Standard Model
Detailed Study / Advanced Class Project — Role: Project Researcher
A detailed study of supersymmetry in particle physics, focusing on the hierarchy problem of the Standard Model, MSSM supermultiplets, particle spectrum, and TeV-scale new physics implications.
Arduino-Based Smoke Detection and Fire Alarm System
Academic Electronics & Laboratory Project — Role: Student Investigator
An academic laboratory electronics project designing and implementing an automated smoke detection and fire alarm alerting system using microcontroller sensors and signal conditioning.
Green Functions and Their Applications in Physics
BSc (Honours) Undergraduate Project — Role: Undergraduate Researcher
A study of Green's-function methods and their applications to solving physical problems involving differential equations in electrostatics, quantum mechanics, and wave propagation.
Ramakrishna Mission Residential College, University of Calcutta
Scientific Collaborations & Research Discussions
Santanu Pradhan welcomes scholarly discussions on Quantum Measurement & Precision Metrology, Buffer Gas Physics (Current Project), Optical Magnetometry & Atomic Sensors, Laser-Cooled Cold Atoms & Optical Trapping, Graphene & 2D Quantum Optomechanics, Quantum Information Theory & Weak Values, Gravitational Physics & Black Holes (Earlier Work), Computational Physics & Numerical Methods.