THEORETICAL ASTROPHYSICS

Why do galaxies and plasmas evolve as they do?

I’m Uddipan Banik, a theoretical astrophysicist and Yakov B. Zel’dovich Fellow at the Perimeter Institute for Theoretical Physics. I use analytical theory and numerical simulations to study the non-linear relaxation of galaxies and dark matter halos, and astrophysical plasmas ranging from stellar interiors to accretion disks around black holes.

Explore my research View publications

PhD, Yale University · 2023•Former Member, Institute for Advanced Study

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01 / ABOUT

About my research.

Uddipan Banik · Perimeter Institute for Theoretical Physics

My research spans the dynamics of galaxies, dark matter halos and plasmas. I study how gravity and electromagnetic forces drive the relaxation of many-body astrophysical systems.

At Yale, I developed kinetic theories of dynamical friction and phase-space spirals in galaxies. My postdoctoral work explains the formation of dark matter halo profiles and non-thermal particle distributions, and investigates the magnetic cycles of the Sun and accretion disks.

See the research themes

02 / RESEARCH

Research areas.

During my PhD, I studied how gravitational perturbations reshape galaxies. My postdoctoral research uses kinetic theory to study dark matter halo profiles and particle acceleration in plasmas, and MHD to investigate magnetic-field generation and cycles in the Sun and accretion disks.

01PHD RESEARCH · YALE UNIVERSITY

Galaxies &
dark matter.

In my PhD research, I developed theories of how galaxies and dark matter halos respond to gravitational perturbations. I studied how encounters with satellite galaxies generate phase-space spirals in stellar disks and how resonant orbits drive dynamical friction, buoyancy, and core-stalling.

Galactic dynamicsPhase-space spiralsDynamical frictionDark matter halos

▶ Watch the full galaxy-merger movie

02POSTDOCTORAL RESEARCH

Dark matter, plasmas &
dynamos.

My postdoctoral work uses kinetic theory to study the origin of universal dark matter halo profiles and non-thermal particle acceleration in collisionless plasmas, and MHD to understand how large-scale magnetic fields arise and self-organize in the Sun and accretion disks.

Kinetic theoryHalo cusp formationMRI dynamosSolar magnetism

DARK MATTER

Non-thermal electron distribution with a power-law tail

PLASMAS

Late frame of the solar magnetic and velocity fields

DYNAMOS

POSTDOC / 01

A dynamo-wave mechanism for the solar cycle ↗

Exact dynamo-wave solutions and anelastic MHD simulations show how magnetic fields reverse and meridional circulation develops.

Solar magnetism

POSTDOC / 02

Quasilinear halo relaxation ↗

Kinetic theory asks why collisionless dark matter halos can approach familiar density profiles.

Physical Review D · 2025

ONGOING / 03

Dark matter halo profiles ↗

Boltzmann–Poisson theory connects collapse, accretion and substructure to prompt cusps and halo profiles.

Submitted to Physical Review D

POSTDOC / 04

Particles beyond thermal equilibrium ↗

Collective plasma physics shapes non-thermal particle tails, heating and solar-coronal temperatures.

Journal articles + preprints

POSTDOC / 05

Magnetic cycles in accretion disks ↗

Wave interference and shearing-box simulations probe the slow MRI dynamo.

2026 preprint

ONGOING / 06

Quantum many-body relaxation ↗

Quantum kinetics examines stationary states, correlations and the path to thermalization.

Ongoing research

PHD / 07

Stellar motion as a cosmic record ↗

Phase-space spirals and gravitational drag reveal how galaxies respond to perturbations.

PhD research

SOFTWARE / 08

VENUS numerical solver ↗

A kinetic-gravity computational laboratory for dark matter evolution and relativistic collapse.

Ongoing software

Explore all research themes

03 / RESEARCH IN MOTION

Research in motion.

Figures and simulations from my papers, ongoing projects, and research talks. Select a visual to see the full result.

The animations open at full length, with late-time stills displayed before playback.

04 / WRITING

Publications & preprints.

Selected submitted manuscripts, refereed papers, codes, and work in preparation are listed below.

Submitted manuscripts

“Non-linear dynamo waves in magnetized shear flows: a candidate mechanism for the solar cycle” (arXiv:2609.30367)
Uddipan Banik
Submitted to Physical Review E
“A Boltzmann–Poisson theory for violent relaxation in cold dark matter: origin of prompt cusps and NFW halos”
Uddipan Banik, Scott Tremaine, Frank C. van den Bosch, Sachiet Kapur and Kaushik Bhattacharya
Submitted to Physical Review D
“Wave interference as the origin of the cyclic magnetorotational dynamo in accretion disks: insights from weakly nonlinear theory and local shearing box simulations” (arXiv:2605.02996)
Uddipan Banik, Amitava Bhattacharjee and James M. Stone
Submitted to Physical Review Research
“Non-thermal particle acceleration in multi-species kinetic plasmas: universal power-law distribution functions and temperature inversion in the solar corona” (arXiv:2601.03344)
Uddipan Banik and Amitava Bhattacharjee
Submitted to Physics of Plasmas (special topic: invited papers from the 67th annual meeting of APS-DPP)
“Universal power-law distribution functions in an electromagnetic kinetic plasma: implications for the inverted temperature profile in the solar corona” (arXiv:2508.08361)
Uddipan Banik and Amitava Bhattacharjee
Submitted to The Astrophysical Journal Letters

First author refereed publications

“Collisionless relaxation to equilibrium distributions in cold dark matter halos: Origin of the Navarro-Frenk-White profile” (arXiv:2506.02104)
Uddipan Banik and Amitava Bhattacharjee
Physical Review D, 112, 123009, December 3, 2025
“Universal non-thermal power-law distribution functions from the self-consistent evolution of collisionless electrostatic plasmas” (arXiv:2408.07127)
Uddipan Banik, Amitava Bhattacharjee and Wrick Sengupta
The Astrophysical Journal, Volume 977, Number 1, 91, December 5, 2024
Featured in the Institute Letter, Spring 2025
“Relaxation of weakly collisional plasma: Continuous spectra, discrete eigenmodes, and the decay of echoes” (arXiv:2402.07992)
Uddipan Banik and Amitava Bhattacharjee
Physical Review E, 110, 045204, October 17, 2024
“A Comprehensive Perturbative Formalism for Phase Mixing in Perturbed Disks. II. Phase Spirals in an Inhomogeneous Disk Galaxy with a Non-responsive Dark Matter Halo” (arXiv:2303.00034)
Uddipan Banik, Frank C. van den Bosch and Martin D. Weinberg
The Astrophysical Journal, Volume 952, Number 1, 65, July 18, 2023
“A Comprehensive Perturbative Formalism for Phase Mixing in Perturbed Disks. I. Phase Spirals in an Infinite, Isothermal Slab” (arXiv:2208.05038)
Uddipan Banik, Martin D. Weinberg and Frank C. van den Bosch
The Astrophysical Journal, Volume 935, Number 2, 135, August 23, 2022
“Dynamical Friction, Buoyancy and Core-Stalling. I. A Nonperturbative Orbit-based Analysis”
(arXiv:2112.06944)
Uddipan Banik and Frank C. van den Bosch
The Astrophysical Journal, Volume 926, Number 2, 215, February 25, 2022
“A Self-consistent, Time-dependent Treatment of Dynamical Friction: New Insights Regarding Core Stalling and Dynamical Buoyancy”(arXiv:2103.05004)
Uddipan Banik and Frank C. van den Bosch
The Astrophysical Journal, Volume 912, Number 1, 43, May 3, 2021
“A fully general, non-perturbative treatment of impulsive heating” (arXiv:2010.06632)
Uddipan Banik and Frank C. van den Bosch
Monthly Notices of the Royal Astronomical Society, Volume 502, Issue 1, March 2021, Pages 1441–1455
“Constraining the mass density of free-floating black holes using razor-thin lensing arcs”
(arXiv:1811.00637)
Uddipan Banik, Frank C. van den Bosch, Michael Tremmel, Anupreeta More, Giulia Despali, Surhud More, Simona Vegetti and John P McKean
Monthly Notices of the Royal Astronomical Society, Volume 483, Issue 2, February 2019, Pages 1558–1573
“Self-gravitating fluid systems and galactic dark matter” (arXiv:1606.07875)
Uddipan Banik, Dipanjan Dey, Kaushik Bhattacharya and Tapobrata Sarkar
General Relativity and Gravitation 49, Article number: 116 (2017)

Co-authored refereed publications

“Not all cores are equal: Phase-space origins of dynamical friction, stalling and buoyancy”
(arXiv:2511.11804)
Shashank Dattathri, Frank C. van den Bosch, Uddipan Banik, Martin Weinberg, Priyamvada Natarajan, Zhaozhou Li and Avishai Dekel
The Open Journal of Astrophysics, Volume 9, September 7, 2026
“The Dipole Instability in Gravitational N-body Systems: A Natural Explanation for Lopsidedness and Off-Centered Nuclei in Galaxies” (arXiv:2505.23905)
Shashank Dattathri, Frank C. van den Bosch, Martin D. Weinberg, Uddipan Banik
The Astrophysical Journal, Volume 993, Number 1, 150, Oct 30, 2025
“Exact results in Floquet coin toss for driven integrable models” (arXiv:1705.03662)
Utso Bhattacharya, Somnath Maity, Uddipan Banik and Amit Dutta
Physical Review B 97, 184308, May 2018

Codes

“VENUS”: Vlasov-Einstein NUmerical Solver code in C++ (OpenMP & MPI parallelized, GPU-accelerated), equipped with Einstein-Vlasov, Einstein-Boltzmann, Vlasov-Poisson and Boltzmann-Poisson (CDM and SIDM) modules, for the numerical simulation of non-linear structure formation (virialized halos and black holes) in weakly collisional self-gravitating systems.
“Stellar dynamo solvers for AthenaK and Athena++”: Developed an anelastic MHD solver in AthenaK and Athena++ for stratified, shearing simulations and used it to simulate a solar dynamo with sustained magnetic polarity reversals and meridional circulation resembling solar observations. Developing a fully compressible low-Mach MHD solver in AthenaK for stratified magnetoconvection.
“QKIN”: Quantum KINetic Solver code in C++ (OpenMP & MPI parallelized) for evolving many-body quantum states, with the aim to investigate the relaxation of weakly coupled bosonic and fermionic systems (e.g., degenerate fermions in compact objects, dilute plasmas) towards thermal and non-thermal steady states.
“NP-impulse”: Publicly available code in Python to compute the (non-perturbative) energy transfer and mass loss in impulsive encounters of galaxies and dark matter halos

Publications in preparation

“Self-similar profiles in Einstein-Vlasov systems: from virialized halos to black holes”
Uddipan Banik, Scott Tremaine, Frank C. van den Bosch, Sachiet Kapur and Kaushik Bhattacharya
“Numerical solution to the Einstein-Vlasov system in spherically symmetric gravitational collapse”
Uddipan Banik, Sachiet Kapur, Kaushik Bhattacharya, Frank C. van den Bosch and Scott Tremaine
“Numerical solution to the Einstein-Boltzmann problem: core-collapse and black hole formation in self-interacting dark matter”
Uddipan Banik, Frank C. van den Bosch, Chris Hamilton, Abdelaziz Hussein, Lina Necib, Scott Tremaine, Sachiet Kapur and Kaushik Bhattacharya
“A self-consistent quasilinear theory for non-thermal particle acceleration in magnetized plasmas”
Uddipan Banik, Robert J. Ewart, Alexander A. Schekochihin and Amitava Bhattacharjee
“How fast do supermassive black hole binaries form in galaxy mergers?”
Kavish Sardana, Uddipan Banik, Shashank Dattathri and Frank C. van den Bosch
“Dynamical Friction, Buoyancy and Core-Stalling. II. Inspiral vs libration”
Kavish Sardana, Uddipan Banik, Shashank Dattathri and Frank C. van den Bosch
“Self-gravitating response of galactic disks and the Gaia snail”
Chris Hamilton, Uddipan Banik and Shaunak Modak