Research Themes

My research spans emergent gravity in matrix models, topological structures in classical field theory, noncommutative & quantum geometry, and gauge theory on curved spacetimes — most recent first. A common thread is the use of symmetry and exact methods to get at structures that are hard to reach otherwise.

Current focus: Quantum Riemannian geometry, geodesic flows on quantum spaces, and particle physics from matrix models.

Emergent Gravity & Particle Physics from Quantum Spacetime

Emergent gravity and matrix models

I study whether spacetime, gravity, and the particle content of the universe can all emerge from a single underlying algebraic structure. My current work pursues this from two converging directions. The first is through the IKKT (IIB) matrix model — a candidate non-perturbative formulation of string theory where spacetime is not a background but an output, emerging from large-matrix dynamics. With Harold Steinacker at Vienna, I derived modified Einstein equations from the one-loop effective action for 3+1-dimensional quantum branes, finding extra dilaton, axionic, and anharmonicity contributions [CQG 2024]. At cosmological scales these depart significantly from general relativity and generate extra geometric modes reminiscent of dark matter.

The second direction draws on the normed division algebras — ℝ, ℂ, ℍ, 𝕆 — whose structure appears to encode the symmetries and representations of the Standard Model with remarkable precision. Working with Nichol Furey at HU Berlin and with Shahn Majid at QMUL, I am exploring how division-algebraic models and Quantum Riemannian Geometry can be combined to understand whether the Standard Model is algebraically inevitable — emerging from the geometry of quantum spacetime itself rather than imposed by hand.

Topological & Dynamical Structures in Electromagnetic Theory

Knotted electromagnetic field lines

I study the topological and dynamical structure of vacuum Maxwell fields whose field lines form non-trivial closed knots. These electromagnetic knots carry conserved helicity, finite energy and finite action, and arise naturally from the conformal equivalence between de Sitter space and a compact S3-cylinder — which generates a complete “knot basis” of Maxwell solutions classified by the S3 harmonic spin j. Some of these configurations have since been experimentally realized using laser beams with knotted polarization singularities.

My contributions, developed in collaboration with Olaf Lechtenfeld and others at ITP Hannover, include establishing the knot basis and deriving a clean linear relation between spin and helicity, with a characterisation of the null-field subspace [PLA 2020]; computing all 15 conformal Noether charges for general spin-j combinations, finding that scalar charges either vanish or are proportional to the energy [EPJP 2022]; and numerically tracking the trajectories of charged particles in knotted EM backgrounds, which show intricate sensitivity to initial conditions [JPA 2022].

Exact Gauge Fields on Curved & Symmetric Spacetimes

Minkowski spacetime foliations

I construct exact, closed-form solutions of Yang–Mills gauge theory on curved and symmetric spacetimes — de Sitter, anti-de Sitter, and Minkowski via its non-compact coset structure — where standard perturbative intuition fails and symmetry becomes the primary tool. This work, developed with Olaf Lechtenfeld at ITP Hannover, forms the core of my PhD and postdoctoral research.

The answer is yes, when you exploit symmetry systematically. On de Sitter space, equivariant dimensional reduction reduces the Yang–Mills equations to Newton’s problem in a double-well potential, with solutions in terms of Jacobi elliptic functions [thesis, PLB 2022]. On Minkowski space, identifying the SO(1,3) coset structure yields new exact solutions [PLB 2022]; the anti-de Sitter case adds yet another chapter. Alongside this, a Floquet stability analysis of a cosmological Einstein–Yang–Mills–Higgs proposal showed that all perturbative gauge-field eigenmodes up to su(2) spin j = 2 are unstable [NPB 2021].

Noncommutative & Quantum Geometry

Quantum / fuzzy space

I study the geometry of spaces where coordinates no longer commute — models of quantum spacetime at the Planck scale where the classical continuum gives way to something irreducibly discrete and “fuzzy.” The natural framework is Connes’ Noncommutative geometry: a spectral triple (non-commutative algebra, Hilbert space, Dirac operator) encodes enough geometric data to define distances between “points” now understood as states of the algebra.

My early work with Biswajit Chakraborty at the S.N. Bose National Centre developed a Hilbert–Schmidt operatorial approach for computing spectral distances on the Moyal plane and the fuzzy sphere — systematically avoiding the star-product ambiguities that affect other methods. On the doubled Moyal plane, we reproduced the Pythagorean distance relation between pure states and showed that a Higgs-like scalar emerges from internal fluctuations of the Dirac operator [PRD 2018]. This thread connects directly to my current project with Shahn Majid at QMUL on Quantum Riemannian Geometry — exploring what a genuinely quantum geodesic looks like and what it implies for particle physics.

Affiliations

Mar, 2024 — ~Sep, 2027

School of Mathematical Sciences, Queen Mary University of London

I am currently working with Shahn Majid at QMUL Maths on an ambitious project funded by the German Research Foundation (DFG). The key idea is to understand the nature of quantum spacetime as per Beggs–Majid —e.g. what is a quantum geodesic?—and make use of this drastically new formulation to illuminate particle physics problems.

Jul, 2023 — Feb, 2024

Institute of Physics, Humboldt University Berlin

This short-term postdoc position at HU Berlin with my host Nichol Furey was really fruitful, generously funded by the host’s Freigeist grant from Volkswagen Stiftung. We worked on particle physics applications, combining Nichol’s unique approach to division-algebraic models with my expertise in non-commutative geometry à la Connes.

Summers 2023 & 2024

Erwin Schrödinger Institute, Vienna

These visits, funded by the JRF programme of ESI, led to a fruitful collaboration with Harold Steinacker at the Physics Department of the University of Vienna. We have a paper together on emergent gravity in the IKKT model, published in CQG.

Oct, 2018 — Jun, 2023

Institute for Theoretical Physics (LUH), Hannover

I worked with Olaf Lechtenfeld on various aspects of spacetime geometry in classical gauge theory, first as a doctoral scholar and later as a postdoc. This included works on de Sitter space for both Abelian (EM knots) and non-Abelian (cosmic gauge field) cases during the PhD, and on symmetric spaces as well as anti-de Sitter space during the postdoc.

2013 — 2018 (multiple short visits)

S.N. Bose National Centre for Basic Sciences, Kolkata

I visited the Bose Centre numerous times to collaborate with my favourite mentor Biswajit Chakraborty. A major portion of my research on Noncommutative quantum mechanics and Noncommutative geometry took place during three separate summer visits of over two months each, yielding three published articles.

Publications

For a full overview including citations please visit my InspireHEP or arXiv profile.

Regular articles

  1. Kaushlendra Kumar, Geodesic flows on a black-hole background arXiv:2603.03222. [Mathematica notebook] (2026, preprint)
  2. Savan Hirpara, Kaushlendra Kumar, Olaf Lechtenfeld and Gabriel Picanço Costa, Exact gauge fields from anti-de Sitter space J. Math. Phys. 65 (2024) 072903, arXiv:2301.03606 [hep-th].
  3. Kaushlendra Kumar and Harold Steinacker, Modified Einstein equations from the 1-loop effective action of the IKKT model Class. Quant. Grav. 41 (2024) 18, 185007, arXiv:2312.01317 [hep-th].
  4. Kaushlendra Kumar, Olaf Lechtenfeld, Gabriel Picanço Costa and Jona Röhrig, Yang–Mills solutions on Minkowski space via non-compact coset spaces Phys. Lett. B 835 (2022) 137564, arXiv:2206.12009 [hep-th].
  5. Kaushlendra Kumar, Solutions of Yang–Mills theory in four-dimensional de Sitter space Leibniz Universität Hannover, Diss., 2022, arXiv:2202.12215 [hep-th]. [Mathematica notebook]
  6. Lukas Hantzko, Kaushlendra Kumar and Gabriel Picanço Costa, Conserved charges for rational electromagnetic knots Eur. Phys. J. Plus 137 (2022) 407, arXiv:2106.05952 [math-ph].
  7. Kaushlendra Kumar, Olaf Lechtenfeld and Gabriel Picanço Costa, Trajectories of charged particles in knotted electromagnetic fields J. Phys. A: Math. Theor. 55 (2022) 315401, arXiv:2202.00169 [math-ph]. [Mathematica notebook]
  8. Kaushlendra Kumar, Olaf Lechtenfeld and Gabriel Picanço Costa, Instability of cosmic Yang–Mills fields Nucl. Phys. B 973 (2021) 115583, arXiv:2102.08401 [hep-th].
  9. Kaushlendra Kumar and Olaf Lechtenfeld, On rational electromagnetic fields Phys. Lett. A 384 (2020) 126445, arXiv:2002.01005 [hep-th].
  10. Kaushlendra Kumar and Biswajit Chakraborty, Spectral distances on doubled Moyal plane using Dirac eigen-spinors Phys. Rev. D 97 (2018) 086019, arXiv:1711.00653 [math-ph].
  11. Yendrembam Chaoba Devi, Kaushlendra Kumar, Biswajit Chakraborty and Frederik G. Scholtz, Revisiting Connes’ finite spectral distance on noncommutative spaces: Moyal plane and fuzzy sphere Int. J. Geom. Methods Mod. Phys. 15 (2018) 1850204, arXiv:1611.02493 [hep-th].
  12. Kaushlendra Kumar, Shivraj Prajapat and Biswajit Chakraborty, On the role of Schwinger’s SU(2) generators for simple harmonic oscillator in 2D Moyal plane Eur. Phys. J. Plus 130 (2015) 120, arXiv:1312.3095 [math-ph].

Conference proceedings

  1. Kaushlendra Kumar, On Yang–Mills fields from anti-de Sitter spaces J. Phys.: Conf. Ser. 2667 (2023) 012018.
  2. Kaushlendra Kumar, SO(1,3) Yang–Mills solutions on Minkowski space via cosets SciPost Phys. Proc. 14 (2023) 033, arXiv:2212.01341 [hep-th].

Miscellaneous

Talks

  1. Dec 9, 2025 @Quantum Algebras seminar, QMUL London “Geodesic flows on a black-hole background” [Slides]
  2. May 28, 2024 @Quantum Algebras seminar, QMUL London “Octonions and the Standard Model”
  3. Mar 5, 2024 @Quantum Algebras seminar, QMUL London “Emergence of modified Einstein equation from 1-loop result in IKKT matrix model”
  4. Aug 18, 2023 @Room 316 meeting (Bal) “Emergent gravity from the 1-loop effective action of the IKKT matrix model” [Video] [Slides]
  5. Jul 27, 2023 @QTS12 conference, Prague “Exact gauge fields from Anti-de Sitter space” [Slides]
  6. Jun 28, 2023 @Lechtenfeld’s group meeting, Hannover “Emergent gravity from the 1-loop effective action of the IKKT matrix model”
  7. May 4, 2023 @ESI, Vienna “Exact gauge fields from Anti-de Sitter space” [Slides]
  8. Mar 15, 2023 @Solitons at Work (online) “Exact gauge fields from anti-de Sitter space” [Video] [Slides]
  9. Aug 23, 2022 @String Theory Journal Club, DESY Hamburg “Yang–Mills solutions on Minkowski space via non-compact coset spaces” [Slides]
  10. Jul 18, 2022 @GROUP34 conference, Strasbourg “Yang–Mills solutions on Minkowski space via non-compact coset spaces” [Slides]
  11. Mar 16, 2022 @Solitons at Work (online) “Yang–Mills solutions on Minkowski space via non-compact coset spaces” [Video] [Slides]
  12. Jun 1, 2022 @Lechtenfeld’s group meeting, Hannover “U(1) gauge theory in noncommutative geometry” based on [Dungen & Suijlekom, 2012]
  13. Apr 20, 2022 @Lechtenfeld’s group meeting, Hannover “Spectral triple with real structure on fuzzy sphere” based on [Chakraborty, Nandy & Chakraborty, 2022]
  14. Dec 1, 2021 @Lechtenfeld’s group meeting, Hannover “New Yang–Mills solution on `T_+`”
  15. Jul 7, 2017 @S.N. Bose Centre, Kolkata “Spectral distances on doubled Moyal plane” [Slides]
  16. Nov 4, 2016 @DPS journal club, IISER Kolkata “Angular momentum & simple harmonic oscillator in noncommutative Moyal plane” [Slides]
  17. Jul 11, 2016 @S.N. Bose Centre, Kolkata “Connes spectral distance on non-commutative spaces: fuzzy sphere & doubled Moyal plane” [Slides]

Conferences

  1. Jul 7–11, 2025: A Quantum of Noncommutativity, Ambleside, UK. [Link]
  2. Jul 24–28, 2023: The 12th International Symposium on Quantum Theory and Symmetries, Prague, Czech Republic. [Link]
  3. Feb 06–17, 2023: Vortex Moduli at ICTS Bangalore, India (online). [Link]
  4. Jul 18–22, 2022: The 34th International Colloquium on Group Theoretical Methods in Physics, Strasbourg, France. [Link]
  5. Aug 02–07, 2021: International Congress on Mathematical Physics & Young Researchers Symposium, Geneva, Switzerland. [Link]
  6. Jan 15–19, 2018: Quantum Groups & Noncommutative Geometry, NISER Bhubaneswar, India. [Link]

Schools

  1. Aug 29–Sep 09, 2022: 28th Saalburg Summer School “Modern methods in QFT”, Bayrischzell, Germany. [Link]
  2. Aug 30–Sep 10, 2021: 27th Saalburg Summer School “Gravitational waves and Black holes”, Heigenbrücken, Germany. [Link]
  3. Aug 31–Sep 11, 2020: 26th Saalburg Summer School “QFT, Integrable systems & string field theory”, Heigenbrücken, Germany. [Link]
  4. Sep 23–27, 2019: Summer School “Special Holonomy—Geometry and Physics”, Freiburg, Germany. [Link]
  5. Sep 02–13, 2019: 25th Saalburg Summer School “Asymptotic symmetries and Hamiltonian formulation”, Heigenbrücken, Germany. [Link]
  6. Nov 06–24, 2017: Preschool & Advanced school “Geometry, Groups and Dynamics”, ICTS Bangalore, India. [Link]