About Me
I am a theoretical physicist and a recent PhD graduate from the Indian Institute of Technology Ropar. My research lies at the intersection of condensed matter physics and quantum gases, with a primary focus on exotic states of matter like supersolids.
My doctoral work explored the rich physics of spin-orbit-coupled spinor Bose-Einstein condensates, where I investigated their collective excitations, quantum phase transitions, non-equilibrium coarsening dynamics, and the influence of finite temperatures. I am passionate about using analytical and numerical tools to unravel complex many-body quantum phenomena and am actively seeking research opportunities and collaborations to contribute to new scientific frontiers.
Research Interests
Ultracold Quantum Gases and Spinor Condensates
Investigating the ground state properties, quantum phase transitions, collective excitations, and non-equilibrium dynamics in spin-orbit-coupled, coherently coupled, and dipolar Bose-Einstein condensates (BECs).
Non-Equilibrium and Finite-Temperature Dynamics
Universal coarsening phenomena and defect dynamics in quenched quantum systems, Stochastic methods (SPGPE, SGPE) for real-time thermal dynamics, Hartree–Fock–Bogoliubov–Popov theory for spinor condensates.
Quantum Fluids of Light and Polaron Physics
Non-equilibrium dynamics and superfluidity in exciton-polariton condensates, Impurity physics (polarons) in BECs and polaron-polaritons in driven-dissipative systems.
Research Highlights
Universal Coarsening Dynamics
Demonstrated that domain growth in quenched quasi-2D spin-1 SOC BECs follows a universal power-law, placing them in the same dynamical class as other binary fluids and confirming robust non-equilibrium behavior.
Enhancing and Melting of Supersolidity
Demonstrated that thermal fluctuations can enhance quantum order by stabilizing and enlarging the supersolid stripe phase in quasi-1D systems. This counter-intuitive finding reveals a novel mechanism for tuning quantum critical points, contrasting with typical melting in uniform 3D systems.
Collective Excitation Spectra
Calculated low-lying excitation modes (dipole, breathing, spin-dipole) to precisely map phase boundaries via mode softening and identify double roton instabilities, providing key signatures for experimental verification of many-body states.
Advanced Numerical Methods
Developed and implemented a suite of Fortran and Mathematica codes, including Bogoliubov-de Gennes solvers and stochastic GPE methods (SGPE/SPGPE), to accurately model fluctuations and real-time dynamics in open quantum systems.
Skills & Expertise
Technical Skills
Programming Languages
Numerical Libraries & HPC
Theoretical Expertise
Core Theories
Quantum Many-Body Theory, Mean-Field & Bogoliubov-de Gennes (BdG) Theory, Hartree-Fock-Bogoliubov-Popov (HFBP) Theory.
Numerical & Simulation Methods
Stochastic Gross-Pitaevskii Equation (SGPE/SPGPE), Finite-Difference & Pseudospectral Methods, Eigensolvers for PDEs.
Publications
Peer-Reviewed Articles
Preprints
Rajat, Ritu, and S. Gautam, Universal coarsening dynamics of supersolid stripe phase of spin-orbit-coupled spinor Bose-Einstein condensates (Manuscript in preparation).
S. Kumar, Rajat, A. Roy, and S. Gautam, Excitations at zero and finite temperatures in coherently coupled Bose-Einstein condensates (Manuscript in preparation).
Conference Presentations
Oral Presentations
Collective Excitations and Universal Coarsening Dynamics of a spin-orbit-coupled spin-1 Bose–Einstein condensate
PHYCON 2025, IIT Ropar, India (Mar 2025)
🏆 Best Oral Presentation Award
Temperature-induced supersolidity in spin-orbit-coupled Bose gases
QMAT2024, IIT Guwahati, India (Dec 2024)
Temperature-induced supersolidity in spin-orbit-coupled Bose gases
Physics Day, IIT Ropar, India (Mar 2024)
Poster Presentations
Temperature-induced Supersolidity in Spin-Orbit-Coupled Bose Gases
International Conference on BEC, SNBNCBS, Kolkata, India (Nov 2024)
Temperature-induced Supersolidity in Spin-Orbit-Coupled Bose Gases
Ultracold Atoms Japan 2024, OIST, Japan (Apr 2024)
Collective Excitations in Cigar-Shaped Spin-Orbit-Coupled Spin-1 BECs
Quantum Technologies with UltraCold Atoms, IISER Pune, India (Nov 2023)
Experience
Dec 2019 – Jun 2025
PhD in Physics
Indian Institute of Technology Ropar, India
Thesis: Collective excitations and coarsening dynamics of spin-orbit-coupled spinor condensates.
Jun 2019 – Dec 2019
Junior Research Fellow
Indian Institute of Technology Ropar, India