Kabir Khanna

With Sir Roger Penrose after his talk

Wadham College, Oxford

Hey all 👋🏾 ! I’m Kabir, a first year PhD student at UMass Amherst. I work with Prof. Romain Vasseur on topics related to quantum dynamics using tools in quantum computing and quantum information theory. However, I am interested in all things quantum condensed matter theory.

As far as theoretical physicists go, I have a non-traditional academic background. I graduated with a bachelor’s in Engineering Design and a master’s in Quantum Science & Technology from the Indian Institute of Technology Madras (IITM) in July 2022.

I also hold an MSc in Mathematical and Theoretical Physics from the University of Oxford, a short yet intense course in theoretical physics. You can find the list of courses offered here.

Besides physics, I like to learn languages, geek out about coffee, and if the circumstances call for it, go all out with my guitar.

News

Sep 5, 2023	Started my PhD!
Mar 6, 2023	I have officially accepted a PhD offer at University of Massachusetts Amherst under the supervision of Prof. Romain Vasseur!
Feb 20, 2023	My second paper is out on arXiv! Part of this is the work done during my master’s project at IITM.
Oct 2, 2022	I started my MSc in theoretical physics at the University of Oxford!
Sep 22, 2022	My first paper is out on arXiv! 🎊
Aug 30, 2022	Website is live!! 📈

Publications

ArXiv

Decoherence due to Spacetime Curvature

Raghvendra Singh, Kabir Khanna, and Dawood Kothawala

2023

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There has been considerable interest over the past years in investigating the role of gravity in quantum phenomenon such as entanglement and decoherence. In particular, gravitational time dilation is believed to decohere superpositions of center of mass of composite quantum systems. Since true effects of gravity are encoded in the curvature of spacetime, the universality of such a decoherence must be characterized through components of Riemann tensor Rabcd, with a clear separation from non-inertial kinematic effects. We obtain the reduced density matrix of a composite system in a generic curved spacetime, and express the decoherence time scale explicitly in terms of curvature. The decoherence in an inertial frame is caused by tidal acceleration. We also analyse the effects of self-gravity and show that the coupling of gravitational interaction with external curvature can not be captured by the replacement m→m+Hint/c2.
ArXiv

GUP Corrections to the Jaynes-Cummings Model

Kabir Khanna, and Saurya Das

Sep 2022

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The Generalized Uncertainty Principle (GUP) is a modification of Heisenberg’s Uncertainty Principle predicted by several theories of quantum gravity. In this work, we compute GUP corrections to the well-known Jaynes-Cummings Model (JCM) with the aim of eventually observing quantum gravity effects in quantum optical systems. To this end, we first analytically solve the GUP-corrected JCM and obtain the corrected Rabi frequency in the quadratic GUP model. Following this, we calculate the effects of a dispersive interaction with light in a coherent state and show that this gives rise to photon-added coherent states that were first studied by Agarwal and Tara in 1991. The latter causes a change in the value of the Wigner function, which if detected in the laboratory, would in effect be a signature of quantum gravity.