arXiv subjects

Aditya Verma

Publications and source records attributed to Aditya Verma.

4 recordsLinked to original sources

arXiv2026

Sub-cycle doublon-holon dynamics in one-dimensional Mott insulators revealed by two-color high-harmonic spectroscopy

Solid-state high-harmonic spectroscopy is becoming an emerging tool for probing nonequilibrium many-body dynamics. Yet, direct measurements of strongly driven, sub-optical-cycle dynamics in correlated materials during high-harmonic emission remain largely unexplored. Here, we measure high-harmonic emission chirp in a prototypical one-dimensional Mott insulator, which encodes strongly driven doublon-holon dynamics at sub-optical-cycle timescales. We observe a positive chirp for above band gap harmonics, indicating that high harmonics are dominated by doublon-holon recombinations. We further show a harmonic order-dependent dephasing, which can be understood through different doublon-holon excursion distances associated with each harmonic. These results reveal coherent doublon-holon dynamics and their ultrafast dephasing in Mott insulators, which is relevant to other nonequilibrium light-induced phenomena, such as Floquet engineering.

cond-mat.str-el↗

arXiv2026

First Plasma Commissioning and Operational Highlights from India's First Spherical Tokamak at IPR

A compact Spherical Tokamak(ST) is commissioned at Institute for Plasma Research (IPR) to explore low aspect ratio tokamak physics and technologies that complement to the existing high aspect ratio tokamaks namely ADITYA-U and SST-1 by enabling studies on non-inductive startup, current drive in over dense plasmas, and shaped plasma physics on a low cost platform. The device, India's first spherical tokamak has completed major mechanical, magnetic, and electrical integration, and the coil system has been successfully tested with series of integrated commissioning. First plasma experiments have been carried out with a modest Ohmic system assisted by a 2.45GHz microwave system, supported by a centralized control and data acquisition system. An initial diagnostic set comprising visible imaging, spectroscopy, magnetics, and radiation monitors required for machine operation has been installed. This paper presents the integrated commissioning experiences and first plasma experiments of the newly installed machine.

physics.plasm-ph↗

arXiv2026

High-rate Scalable Entanglement Swapping Between Remote Entanglement Sources on Deployed New York City Fibers

Entanglement swapping between photon pairs generated at physically separated nodes over telecommunication fiber infrastructure is an essential step towards the quantum internet, enabling applications such as quantum repeaters, blind quantum computing, distributed quantum computing, and distributed quantum sensing. However, successful networked entanglement swapping relies on generating indistinguishable pairs of photons and preserving them over deployed fibers. This has limited most previous demonstrations to laboratory settings or relied on sophisticated methods to maintain the necessary indistinguishability. Here, we demonstrate a scalable entanglement swapping experiment using naturally indistinguishable entanglement sources based on warm atomic vapor cells. Without sharing lasers or optical frequency references between nodes, nor the need for pulsing the sources, we achieve a swapping rate of nearly 500 pairs/s while maintaining the CHSH parameter above 2. Additionally, we demonstrate the scalability of our method by maintaining the quality of the entanglement swapping on 17.6-km of deployed fibers in NYC, relying on commercially available SPADs at the spoke nodes, SNSPDs at the hub and standard time-synchronization techniques. Our work paves the way for the practical deployment of large-scale hub-and-spoke quantum networks within cities and data centers.

quant-ph↗

arXiv2025

Dynamical reconstruction of SPARC galactic halos within self-interacting fuzzy dark matter

Fuzzy Dark Matter with non-zero quartic self-interaction (SFDM) is shown to be a viable model for simultaneously fitting 17 dark-matter-dominated galaxies from the SPARC database with a single $(m,g)$ point in the space of boson masses and self-coupling constants: $\log_{10}\left(m \,[\mathrm{eV}/c^2] \right) = \log_{10}(1.98)-22^{+0.8}_{-0.6}$ and $\log_{10}\left(g \, [\mathrm{eV \, m}^3/kg] \right) = \log_{10}(9.08)-10^{+0.4}_{-1.2}$. This is based on the combination of an appropriately constructed static super-Gaussian profile for the inner galactic core (`soliton') region, and a Navarro-Frenk-White profile for the surrounding halo region. The explicit identification of a non-zero interaction strength may resolve issues of inconsistent constraints in non-interacting FDM. Our identification of these parameters enables the explicit {\em dynamical} reconstruction of potential host halos for such galaxies through numerical solution of the SFDM equations; we outline a {proof-of-principle procedure via merger simulations} for two galaxies (UGCA444, UGC07866), and show that this yields viable rotation curves over a dynamical period of ${\cal O}(1) \, Gyr$.

astro-ph.CO↗