Parampreet Singh

Param Singh

Ball Family Distinguished Professor of Physics

Department Chair

Adjunct Faculty, LSU Center for Computation and Technology

PhD: 2004, Inter-University Center for Astronomy & Astrophysics (IUCAA),
University of Pune
Email: psingh@lsu.edu
Phone: 225-578-7283
Office: 202-K  Nicholson Hall, Tower Dr., Baton Rouge, LA 70803-4001

Research Webpage

 

Research Interests

Quantum Gravity and Cosmology

My research addresses some of the most fundamental and long standing questions in physics: how did our universe begin, what happens to spacetime beyond the big bang, and what is the fate of the singularities hidden inside black holes. Classical general relativity predicts that these singularities are unavoidable, yet it is widely expected that a quantum theory of gravity will change this picture. My work aims to make that expectation precise, using a combination of rigorous analytical methods and high performance computing.

A central part of my research uses loop quantum cosmology. With Abhay Ashtekar and Tomasz Pawlowski, I co-developed what is known in the literature as the APS model. Its central result is that quantum geometry resolves the big bang singularity and replaces it with a big bounce. The APS model has become the standard framework of loop quantum cosmology, and research groups around the world working on the bounce in isotropic, anisotropic, and inhomogeneous spacetimes either build directly on it or measure their results against it.

With Abhay Ashtekar and Javier Olmedo, I later co-developed the AOS model, the first complete quantum gravitational description of a black hole that covers both its interior and exterior regions. It shows that the singularity at the heart of a black hole is not a fundamental feature of nature but an artifact of classical physics that quantum geometry naturally resolves, giving a consistent quantum extension of the full black hole spacetime.

Building on these frameworks, my current work explores the physical and observational consequences of quantum geometry. This includes the tidal deformability of loop quantum black holes through their Love numbers, with implications for gravitational wave observations, the imprint of Planck scale physics on the cosmic microwave background, the fate of gravitational collapse and the question of covariance in effective models, and the quantum complexity of black holes and of the early universe. My research spans the foundational, phenomenological, technical, and conceptual sides of the field.

Selected Publications

  • Meysam Motaharfar, Maxwell R. Siebersma and Parampreet Singh, Quantum cosmology in Krylov space: complexity and entropy, Entropy 28, 802 (2026).
  • Meysam Motaharfar and Parampreet Singh, Love numbers of covariant loop quantum black holes, Phys. Rev. D 112, 066008 (2025).
  • Loop quantum gravitational signatures via Love numbers, Phys. Rev. D 111, 106018 (2025).
  • Kristina Giesel, Hongguang Liu, Parampreet Singh and Stefan Weigl, Generalized analysis of a dust collapse in effective loop quantum gravity: fate of shocks and covariance, Phys. Rev. D 110, 104016 (2024).
  • Bao-Fei Li, Meysam Motaharfar and Parampreet Singh, Constraining regularization ambiguities in loop quantum cosmology via the CMB, Phys. Rev. D 110, 066005 (2024).
  • Bao-Fei Li and Parampreet Singh, Loop quantum cosmology: physics of singularity resolution and its implications, invited review, arXiv:2304.05426 (2024).
  • Bao-Fei Li, Sahil Saini and Parampreet Singh, Primordial power spectrum from a matter-ekpyrotic bounce scenario in loop quantum cosmology, Phys. Rev. D 103, 066020 (2021).
  • Sahil Saini and Parampreet Singh, Von Neumann stability of modified loop quantum cosmologies, Class. Quant. Grav. 36, 105010 (2019).
  • Sahil Saini and Parampreet Singh, Generic absence of strong singularities and geodesic completeness in modified loop quantum cosmologies, Class. Quant. Grav. 36, 105014 (2019).
  • Abhay Ashtekar, Javier Olmedo and Parampreet Singh, Quantum transfiguration of Kruskal black holes, Phys. Rev. Lett. 121, 241301 (2018), Editor's Suggestion. The AOS model.
  • Sahil Saini and Parampreet Singh, Resolution of strong singularities and geodesic completeness in loop quantum Bianchi-II spacetimes, Class. Quant. Grav. 34, 235006 (2017).
  • Sahil Saini and Parampreet Singh, Geodesic completeness and the lack of strong singularities in effective loop quantum Kantowski-Sachs spacetime, Class. Quant. Grav. 33, 245019 (2016).
  • Peter Diener, Brajesh Gupt, Miguel Megevand and Parampreet Singh, Numerical evolution of squeezed and non-Gaussian states in loop quantum cosmology, Class. Quant. Grav. 31, 165006 (2014).
  • Peter Diener, Brajesh Gupt and Parampreet Singh, Numerical simulations of a loop quantum cosmos: robustness of the quantum bounce and the validity of effective dynamics, Class. Quant. Grav. 31, 105015 (2014).
  • Peter Diener, Brajesh Gupt and Parampreet Singh, Chimera: a hybrid approach to numerical loop quantum cosmology, Class. Quant. Grav. 31, 025013 (2014).
  • Parampreet Singh, Loop quantum cosmology and the fate of cosmological singularities, invited review based on the Vainu Bappu Gold Medal Award lecture, Bull. Astr. Soc. India 42, 121 (2014).
  • David Craig and Parampreet Singh, Consistent probabilities in loop quantum cosmology, Class. Quant. Grav. 30, 205008 (2013).
  • Parampreet Singh, Numerical loop quantum cosmology: an overview, invited review, Class. Quant. Grav. 29, 244002 (2012).
  • Abhay Ashtekar and Parampreet Singh, Loop quantum cosmology: a status report, invited topical review, Class. Quant. Grav. 28, 213001 (2011).
  • Parampreet Singh, Are loop quantum cosmos never singular? Class. Quant. Grav. 26, 125005 (2009). Selected for Research Highlights of 2008-2009 by Classical and Quantum Gravity.
  • Alejandro Corichi and Parampreet Singh, Quantum bounce and cosmic recall, Phys. Rev. Lett. 100, 161302 (2008).
  • Abhay Ashtekar, Tomasz Pawlowski and Parampreet Singh, Quantum nature of the big bang: improved dynamics, Phys. Rev. D 74, 084003 (2006).
  • Rituparno Goswami, Pankaj S. Joshi and Parampreet Singh, Quantum evaporation of a naked singularity, Phys. Rev. Lett. 96, 031302 (2005).
  • Martin Bojowald, Rituparno Goswami, Roy Maartens and Parampreet Singh, A black hole mass threshold from non-singular quantum gravitational collapse, Phys. Rev. Lett. 95, 091302 (2005).
  • Shinji Tsujikawa, Parampreet Singh and Roy Maartens, Loop quantum gravity effects on inflation and the CMB, Class. Quant. Grav. 21, 5767 (2004).