Publications

Order by: publication date number of citations

• The scalar and tensor glueball in production and decay

  Eberhard Klempt

  SciPost Phys. Proc. 6, 001 (2022) · published 31 May 2022 | Toggle abstract · pdf

  Evidence for the scalar and the tensor glueball is reported. The evidence stems from an analysis of BESIII data on radiative $J/\psi$ data into $\pi^0\pi^0$, $K_SK_S$, $\eta\eta$, and $\phi\omega$ [1]. The coupled-channel analysis is contrained by a large number of further data. The scalar intensity is described by ten scalar isoscalar mesons, covering the range from $f_0(500)$ to $f_0(2330)$. Five resonances are interpreted as mainly-singlet states in SU(3), five as mainly-octet states. The mainly-singlet resonances are produced over the full mass range, the production of octet states is limited to the 1500 to 2100 MeV mass range and shows a large peak. The peak is interpreted as scalar glueball. Its mass, width and yield are determined to $\rm M_{glueball}=(1865\pm 25)$ MeV, $\Gamma_{\rm glueball} =\rm (370\pm 50^{+30}_{-20}) MeV$, $\rm Y_{J/\psi\to \gamma G_0}=(5.8\pm1.0)\cdot 10^{-3}$. The study of the decays of the scalar mesons identifies significant glueball fractions [2]. The tensor wave shows the $f_2(1270)$ and $f_2'(1525)$ and a small enhancement at $M=2210\pm40$ MeV, $\Gamma=\rm (355^{+60}_{-30}) MeV$ [3]. An interpretation of these data is suggested.

  1 citation

• Probabilistic deconstruction of a theory of gravity, part II: Curved space

  Sunok Josephine Suh

  SciPost Phys. 16, 012 (2024) · published 17 January 2024 | Toggle abstract · pdf

  We propose that the underlying context of holographic duality and the Ryu-Takayanagi formula is that the volume measure of spacetime is a probability measure constrained by quantum dynamics. We define quantum stochastic processes using joint quantum distributions which are realized in a quantum system as expectation values of products of projectors. In anti-de Sitter JT gravity, we show that Einstein's equations arise from the evolution of probability under the quantum stochastic process induced by the boundary, with the area of compactified space in the gravitational theory identified as a probability density evolving under the quantum process. Extrapolating these and related results in flat JT gravity found in [SciPost Phys. 15, 174 (2023)], we conjecture that general relativity arises in the semi-classical limit of the evolution of probability with respect to quantum stochastic processes.

  1 citation

• Non-stabilizerness of Sachdev-Ye-Kitaev model

  Surajit Bera, Marco Schirò

  SciPost Phys. 19, 159 (2025) · published 18 December 2025 | Toggle abstract · pdf

  We study the non-stabilizerness or quantum magic of the Sachdev-Ye-Kitaev ($\mathrm{SYK}$) model, a prototype example of maximally chaotic quantum matter. We show that the Majorana spectrum of its ground state, encoding the spreading of the state in the Majorana basis, displays a Gaussian distribution as expected for chaotic quantum many-body systems. We compare our results with the case of the $\mathrm{SYK_2}$ model, describing non-chaotic random free fermions, and show that the Majorana spectrum is qualitatively different in the two cases, featuring an exponential Laplace distribution for the $\mathrm{SYK_2}$ model rather than a Gaussian. From the spectrum we extract the Stabilizer Renyi Entropy (SRE) and show that for both models it displays a linear scaling with system size, with a prefactor that is larger for the SYK model, which has therefore higher magic. Finally, we discuss the spreading of quantun magic under unitary dynamics, as described by the evolution of the Majorana spectrum and the Stabilizer Renyi Entropy starting from a stabilizer state. We show that the SRE for the $\mathrm{SYK_2}$ model equilibrates rapidly, but that in the steady-state the interacting chaotic SYK model has more magic than the simple $\mathrm{SYK_2}$. Our results suggest that the Majorana spectrum is qualitatively distinct in chaotic and non-chaotic many-body systems.

  1 citation

• Codebase release 1.0 for evortran

  Thomas Biekötter

  SciPost Phys. Codebases 64-r1.0 (2026) · published 27 January 2026 | Toggle abstract · src

  evortran is a modern Fortran library designed for high-performance genetic algorithms and evolutionary optimization. evortran can be used to tackle a wide range of problems in high-energy physics and beyond, such as derivative-free parameter optimization, complex search taks, parameter scans and fitting experimental data under the presence of instrumental noise. The library is built as an fpm package with flexibility and efficiency in mind, while also offering a simple installation process, user interface and integration into existing Fortran (or Python) programs. evortran offers a variety of selection, crossover, mutation and elitism strategies, with which users can tailor an evolutionary algorithm to their specific needs. evortran supports different abstraction levels: from operating directly on individuals and populations, to running full evolutionary cycles, and even enabling migration between independently evolving populations to enhance convergence and maintain diversity. In this paper, we present the functionality of the evortran library, demonstrate its capabilities with example benchmark applications, and compare its performance with existing genetic algorithm frameworks. As physics-motivated applications, we use evortran to confront extended Higgs sectors with LHC data and to reconstruct gravitational wave spectra and the underlying physical parameters from LISA mock data, demonstrating its effectiveness in realistic, data-driven scenarios.

  1 citation

• On perturbation around closed exclusion processes

  Masataka Watanabe

  SciPost Phys. 17, 092 (2024) · published 25 September 2024 | Toggle abstract · pdf

  We derive the formula for the stationary states of particle-number conserving exclusion processes infinitesimally perturbed by inhomogeneous adsorption and desorption. The formula not only proves but also generalises the conjecture proposed in [Phys. Rev. E 97, 032135] to account for inhomogeneous adsorption and desorption. As an application of the formula, we draw part of the phase diagrams of the open asymmetric simple exclusion process with and without Langmuir kinetics, correctly reproducing known results.

  1 citation

• Mechanically-driven stem cell separation in tissues caused by proliferating daughter cells

  Johannes C. Krämer, Edouard Hannezo, Gerhard Gompper, Jens Elgeti

  SciPost Phys. 16, 097 (2024) · published 8 April 2024 | Toggle abstract · pdf

  The homeostasis of epithelial tissue relies on a balance between the self-renewal of stem cell populations, cellular differentiation, and loss. Although this balance needs to be tightly regulated to avoid pathologies, such as tumor growth, the regulatory mechanisms, both cell-intrinsic and collective, which ensure tissue steady-state are still poorly understood. Here, we develop a computational model that incorporates basic assumptions of stem cell renewal into distinct populations and mechanical interactions between cells. We find that the model generates unexpected dynamic features: stem cells repel each other in the bulk tissue and are thus found rather isolated, as in a number of in vivo contexts. By mapping the system onto a gas of passive Brownian particles with effective repulsive interactions, that arise from the generated flows of differentiated cells, we show that we can quantitatively describe such stem cell distribution in tissues. The interaction potential between a pair of stem cells decays exponentially with a characteristic length that spans several cell sizes, corresponding to the volume of cells generated per stem cell division. Our findings may help understanding the dynamics of normal and cancerous epithelial tissues.

  1 citation

• Generalized symmetries of non-SUSY and discrete torsion string backgrounds

  Noah Braeger, Vivek Chakrabhavi, Jonathan J. Heckman, Max Hübner

  SciPost Phys. 19, 160 (2025) · published 18 December 2025 | Toggle abstract · pdf

  String / M-theory backgrounds with degrees of freedom at a localized singularity provide a general template for generating strongly correlated systems decoupled from lower-dimensional gravity. There are by now several complementary procedures for extracting the associated generalized symmetry data from orbifolds of the form $\mathbb{R}^6 / \Gamma$, including methods based on the boundary topology of the asymptotic geometry, as well as the adjacency matrix for fermionic degrees of freedom in the quiver gauge theory of probe branes. In this paper we show that this match between the two methods also works in non-supersymmetric and discrete torsion backgrounds. In particular, a refinement of geometric boundary data based on Chen-Ruan cohomology matches the expected answer based on quiver data. Additionally, we also show that free (i.e., non-torsion) factors count the number of higher-dimensional branes which couple to the localized singularity. We use this to also extract quadratic pairing terms in the associated symmetry theory (SymTh) for these systems, and explain how these considerations generalize to a broader class of backgrounds.

  1 citation

• Codebase release 1.1 for QDsim

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

  SciPost Phys. Codebases 46-r1.1 (2025) · published 23 January 2025 | Toggle abstract · src

  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

• Lepton flavor violation at FCC-ee and CEPC

  Pankaj Munbodh

  SciPost Phys. Proc. 17, 006 (2025) · published 23 July 2025 | Toggle abstract · pdf

  Lepton flavor violating processes are highly suppressed in the Standard Model. Therefore, if observed, lepton flavor violation would be a clear indication of new physics beyond the Standard Model. We study the process $e^+e^-\to\tau\mu$ at tree-level in the Standard Model Effective Field Theory both on the $Z$-pole and at higher center-of-mass energies. We show that the constraints derived from the future circular $e^+e^-$ colliders FCC-ee and CEPC, are complementary to those obtained from low-energy tau decays at BaBar and Belle, as well as projections from Belle-II.

  1 citation

• The ITransverse.jl library for transverse tensor network contractions

  Stefano Carignano

  SciPost Phys. Codebases 63 (2026) · published 9 January 2026 | Toggle abstract · pdf

  Transverse contraction methods are extremely promising tools for the efficient contraction of tensor networks associated with the time evolution of quantum many-body systems, allowing in some cases to circumvent the entanglement barrier that would normally prevent the study of quantum dynamics with classical resources. We present here the ITransverse.jl package, written in Julia and based on ITensors.jl, containing several of these high-level algorithms, including novel prescriptions for efficient truncations of temporal matrix product states.

  1 citation