Publications

Order by: publication date number of citations

• Field theory of collinear and noncollinear magnetic order

  Oleg Tchernyshyov

  SciPost Phys. Lect. Notes 85 (2024) · published 5 September 2024 | Toggle abstract · pdf

  These lecture notes from the 2023 Summer School "Principles and applications of symmetry in magnetism" introduce the reader to the classical field theory of ferromagnets and antiferromagnets.

  1 citation

• Duality-Symmetry Enhancement in Maxwell Theory

  Shani Meynet, Daniele Migliorati, Raffaele Savelli, Michele Tortora

  SciPost Phys. 19, 089 (2025) · published 8 October 2025 | Toggle abstract · pdf

  Free Maxwell theory on general four-manifolds may, under certain conditions on the background geometry, exhibit holomorphic factorization in its partition function. We show that when this occurs, new discrete symmetries emerge at orbifold points of the conformal manifold. These symmetries, which act only on a sublattice of flux configurations, are not associated with standard dualities, yet they may carry 't Hooft anomalies, potentially causing the partition function to vanish even in the absence of apparent pathologies. We further explore their non-invertible extensions and argue that their anomalies can account for zeros of the partition function at smooth points in the moduli space.

  1 citation

• Results from recent analysis of KASCADE-Grande data

  Donghwa Kang, J. C. Arteaga-Velázquez, M. Bertaina, A. Chiavassa, K. Daumiller, V. de Souza, R. Engel, A. Gherghel-Lascu, C. Grupen, A. Haungs, J. R. Hörandel, T. Huege, K. -H. Kampert, K. Link, H. J. Mathes, S. Ostapchenko, T. Pierog, D. Rivera-Rangel, M. Roth, H. Schieler, F. G. Schröder, O. Sima, A. Weindl, J. Wochele, J. Zabierowski

  SciPost Phys. Proc. 13, 036 (2023) · published 29 September 2023 | Toggle abstract · pdf

  KASCADE and its extension array of KASCADE-Grande were devoted to measure individual air showers of cosmic rays in the primary energy range of 100 TeV to 1 EeV. The experiment has substantially contributed to investigate the energy spectrum and mass composition of cosmic rays in the transition region from galactic to extragalactic origin of cosmic rays as well as to quantify the characteristics of hadronic interaction models in the air shower development through validity tests using the multi-detector information from KASCADE-Grande. Although the data accumulation was completed in 2013, data analysis is still continuing. Recently, we investigated the reliability of the new hadronic interactions models of the SIBYLL version 2.3d only with the energy spectra from the KASCADE-Grande data. The evolution of the muon content of high energy air showers in the atmosphere is studied as well, using EPOS-LHC, SIBYLL 2.3, QGSJET-II-04 and SIBYLL 2.3c. In this talk, recent results from KASCADE-Grande and the update of the KASCADE Cosmic Ray Data Centre (KCDC) will be discussed.

  1 citation

• QDsim: A user-friendly toolbox for simulating large-scale quantum dot devices

  Valentina Gualtieri, Charles Renshaw-Whitman, Vinicius Hernandes, Eliska Greplova

  SciPost Phys. Codebases 46 (2025) · published 23 January 2025 | Toggle abstract · pdf

  We introduce QDsim, a Python package tailored for the rapid generation of charge stability diagrams in large-scale quantum dot devices, extending beyond traditional double or triple dots. QDsim is founded on the constant interaction model from which we rephrase the task of finding the lowest energy charge configuration as a convex optimization problem. Therefore, we can leverage the existing package CVXPY, in combination with an appropriate powerful solver, for the convex optimization which streamlines the creation of stability diagrams and polytopes. Through multiple examples, we demonstrate how QDsim enables the generation of large-scale dataset that can serve a basis for the training of machine-learning models for automated tuning algorithms. While the package currently does not support quantum effects beyond the constant interaction model, QDsim is a tool that directly addresses the critical need for cost-effective and expeditious data acquisition for better tuning algorithms in order to accelerate the development of semiconductor quantum devices.

  1 citation

• Mean-field theory of first-order quantum superconductor-insulator transition

  Igor Poboiko, Mikhail Feigel'man

  SciPost Phys. 17, 066 (2024) · published 23 August 2024 | Toggle abstract · pdf

  Recent experimental studies on strongly disordered indium oxide films have revealed an unusual first-order quantum phase transition between the superconducting and insulating states (SIT). This transition is characterized by a discontinuous jump from non-zero to zero values of superfluid stiffness at the critical point, contradicting the conventional "scaling scenario" typically associated with SIT. In this paper, we present a theoretical framework for understanding this first-order transition. Our approach is based on the concept of competition between two fundamentally distinct ground states that arise from electron pairs initially localized by strong disorder: the superconducting state and the Coulomb glass insulator. These ground states are distinguished by two crucially different order parameters, suggesting a natural expectation of a discontinuous transition between them at $T=0$. This transition occurs when the magnitudes of the superconducting gap $\Delta$ and the Coulomb gap $E_C$ become comparable. Additionally, we extend our analysis to low non-zero temperatures and provide a mean-field "phase diagram" in the plane of $(T/\Delta,E_C/\Delta)$. Our results reveal the existence of a natural upper bound for the kinetic inductance of strongly disordered superconductors.

  1 citation

• Few-body reactions investigated with the Trojan Horse Method

  Roberta Spartà, Giuseppe G. Rapisarda, Claudio Spitaleri, M. La Cognata, Rosario G. Pizzone, S. Romano, Aurora Tumino

  SciPost Phys. Proc. 3, 033 (2020) · published 26 February 2020 | Toggle abstract · pdf

  The Trojan Horse Method is an indirect method to measure reaction cross sections at energies of interest for nuclear astrophysics, exploiting the nuclei clustering properties. Here it is presented with its general features and detailed for the case of the 2H(d,p)3H and 2H(d,n)3He measurements, where interesting results for astrophysics and energy fusion power plants have been obtained.

• Some recent results on renormalization-group properties of quantum field theories

  Robert Shrock

  SciPost Phys. Proc. 6, 005 (2022) · published 31 May 2022 | Toggle abstract · pdf

  We discuss some higher-loop studies of renormalization-group flows and fixed points in various quantum field theories.

• Boundary chaos: Spectral form factor

  Felix Fritzsch, Tomaž Prosen

  SciPost Phys. 17, 142 (2024) · published 22 November 2024 | Toggle abstract · pdf

  Random matrix spectral correlations is a defining feature of quantum chaos. Here, we study such correlations in a minimal model of chaotic many-body quantum dynamics where interactions are confined to the system's boundary, dubbed boundary chaos, in terms of the spectral form factor and its fluctuations. We exactly calculate the latter in the limit of large local Hilbert space dimension $q$ for different classes of random boundary interactions and find it to coincide with random matrix theory, possibly after a non-zero Thouless time. The latter effect is due to a drastic enhancement of the spectral form factor, when integer time and system size fulfill a resonance condition. We compare our semiclassical (large $q$) results with numerics at small local Hilbert space dimension ($q=2,3$) and observe qualitatively similar features as in the semiclassical regime.

• Multiplicity dependence of charged-particle jet production in pp collisions at 13 TeV with ALICE

  Debjani Banerjee

  SciPost Phys. Proc. 15, 018 (2024) · published 3 April 2024 | Toggle abstract · pdf

  Measurements of jet production and jet properties in pp collisions provide a test of perturbative quantum chromodynamics (pQCD) and form a baseline for similar measurements in heavy ion (A-A) collisions. In this contribution, we report recent ALICE measurements of charged-particle jet production and intra-jet properties, including mean charged-constituent multiplicity and fragmentation distribution for leading jets, in minimum bias pp collisions at $\sqrt{s}$ = 13 TeV. In addition, the event multiplicity dependence of jet production and jet properties in pp collisions at $\sqrt{s}$ = 13 TeV will be presented. Results will be compared with theoretical model predictions.

• The role of the underlying event in the charm-baryon enhancement observed in pp collisions at LHC energies

  Zoltán Varga, Anett Misák, Róbert Vértesi

  SciPost Phys. Proc. 15, 014 (2024) · published 2 April 2024 | Toggle abstract · pdf

  We study the enhanced production of $\Lambda_c$ charmed baryons relative to that of charmed $D^0$ mesons in proton–proton collisions at LHC energies. We simulated collision events with the enhanced color-reconnection model in PYTHIA 8 MC generator and propose measurements based on the comparative use of different event-activity classifiers to identify the source of the charmed-baryon enhancement. We demonstrate that in this enhanced color-reconnection scenario the excess production is primarily linked to the underlying event and not to the production of high-momentum jets.