Publications

Order by: publication date number of citations

• Functional renormalization group approach for signal detection

  Vincent Lahoche, Dine Ousmane Samary, Mohamed Tamaazousti

  SciPost Phys. Core 7, 077 (2024) · published 2 December 2024 | Toggle abstract · pdf

  This review paper utilizes renormalization group techniques for signal detection in nearly continuous positive spectra. We emphasize the universal aspects of the analogue field-theory approach. The primary objective is to present an extended self-consistent construction of the analogue effective field-theory framework for data, which can be interpreted as a maximum entropy model. In particular, we leverage universality arguments to justify the $\mathbb{Z}_2$ symmetry of the classical action, highlighting the existence of both a large-scale (local) regime and a small-scale (nonlocal) regime. Secondly, in relation to noise models, we observe the universal relationship between phase transitions and symmetry breaking near the detection threshold. Finally, we address the challenge of defining the covariance matrix for tensor-like data. Based on the cutting graph prescription, we note the superiority of definitions that rely on complete graphs of large size for data analysis.

• Exotic structures in exotic nuclei

  F. Miguel Marqués

  SciPost Phys. Proc. 3, 001 (2020) · published 24 February 2020 | Toggle abstract · pdf

  Nuclei with proton and neutron numbers away from stability are known as exotic, and provide stringent tests of nuclear models, mainly developed for the description of stable nuclei. However, only the most extreme combinations lead to literally exotic structures, with sometimes unexpected properties. In this contribution we review some selected examples around the neutron dripline of very light elements: neutron halo structures with embedded substructures in the boron chain; the emission of neutron pairs in $^{16}$Be; and the existence of multi-neutron resonances in `superheavy' hydrogen isotopes.

• A field theory representation of sum of powers of principal minors and physical applications

  Morteza Nattagh Najafi, Abolfazl Ramezanpour, Mohammad Ali Rajabpour

  SciPost Phys. Core 8, 051 (2025) · published 12 August 2025 | Toggle abstract · pdf

  We introduce a novel field theory representation for the Sum of Powers of Principal Minors (SPPM), a mathematical construct with profound implications in quantum mechanics and statistical physics. We begin by establishing a Berezin integral formulation of the SPPM problem, showcasing its versatility through various symmetries including $SU(n)$, its subgroups, and particle-hole symmetry. This representation not only facilitates new analytical approaches but also offers deeper insights into the symmetries of complex quantum systems. For instance, it enables the representation of the Hubbard model's partition function in terms of the SPPM problem. We further develop three mean field techniques to approximate SPPM, each providing unique perspectives and utilities: the first method focuses on the evolution of symmetries post-mean field approximation, the second, based on the bosonic representation, enhances our understanding of the stability of mean field results, and the third employs a variational approach to establish a lower bound for SPPM. These methods converge to identical consistency relations and values for SPPM, illustrating their robustness. The practical applications of our theoretical advancements are demonstrated through two compelling case studies. First, we exactly solve the SPPM problem for the Laplacian matrix of a chain, a symmetric tridiagonal matrix, allowing for precise benchmarking of mean-field theory results. Second, we present the first analytical calculation of the Shannon-Rényi entropy for the transverse field Ising chain, revealing critical insights into phase transitions and symmetry breaking in the ferromagnetic phase. This work not only bridges theoretical gaps in understanding principal minors within quantum systems but also sets the stage for future explorations in more complex quantum and statistical physics models.

• Quantum scars and caustics in Majorana billiards

  R. Johanna Zijderveld, A. Mert Bozkurt, Michael Wimmer, İnanç Adagideli

  SciPost Phys. 17, 147 (2024) · published 28 November 2024 | Toggle abstract · pdf

  We demonstrate that the classical dynamics influence the localization behaviour of Majorana wavefunctions in Majorana billiards. By using a connection between Majorana wavefunctions and eigenfunctions of a normal state Hamiltonian, we show that Majorana wavefunctions in both p-wave and s-wave topological superconductors inherit the properties of the underlying normal state eigenfunctions. As an example, we demonstrate that Majorana wavefunctions in topological superconductors with chaotic shapes feature quantum scarring. Furthermore, we show a way to manipulate a localized Majorana wavefunction by altering the underlying classical dynamics using a local potential away from the localization region. Finally, in the presence of chiral symmetry breaking, we find that the Majorana wavefunction in convex-shaped Majorana billiards exhibits caustics formation, reminiscent of a normal state system with magnetic field.

• $t\bar{t}t\bar{t}$: NLO QCD corrections in production and decays for the $3\ell$ channel

  Nikolaos Dimitrakopoulos

  SciPost Phys. Proc. 18, 015 (2026) · published 29 January 2026 | Toggle abstract · pdf

  We discuss the results for the four-top quark production process at the LHC at NLO accuracy in perturbative QCD for the $3\ell$ decay channel. The QCD corrections are applied in both the production and the decay stages of the four top quarks by employing the narrow-width approximation. The spin correlations are therefore preserved at NLO accuracy in QCD without any approximation. We summarize the impact of higher-order QCD effects by highlighting the sensitivity of the results on the cut applied on the invariant mass of the two hardest light jets in the process.

• 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.

• Predictions for off-shell $t\bar{t}Z$ production at the LHC: The complete set of LO and NLO contributions

  Daniele Lombardi

  SciPost Phys. Proc. 18, 014 (2026) · published 29 January 2026 | Toggle abstract · pdf

  We present predictions for the production and decay of a top–antitop pair in association with a $\rm Z$ boson in the multi-lepton decay channel at the LHC. Our results include the complete set of LO and NLO contributions. Since our calculation is based on full matrix elements, off-shell effects are entirely taken into account. Integrated and differential cross-sections are reported for a realistic fiducial setup.

• Physics-informed neural networks viewpoint for solving the Dyson-Schwinger equations of quantum electrodynamics

  Rodrigo Carmo Terin

  SciPost Phys. Core 8, 054 (2025) · published 20 August 2025 | Toggle abstract · pdf

  Physics-informed neural networks (PINNs) are employed to solve the Dyson-Schwinger equations of quantum electrodynamics (QED) in Euclidean space, with a focus on the non-perturbative generation of the fermion's dynamical mass function in the Landau gauge. By inserting the integral equation directly into the loss function, our PINN framework enables a single neural network to learn a continuous and differentiable representation of the mass function over a spectrum of momenta. Also, we benchmark our approach against a traditional numerical algorithm showing the main differences among them. Our novel strategy, which is expected to be extended to other quantum field theories, is the first step towards forefront applications of machine learning in high-level theoretical physics.

• Population genetics: An introduction for physicists

  Andrea Iglesias-Ramas, Samuele Pio Lipani, Rosalind J. Allen

  SciPost Phys. Lect. Notes 89 (2024) · published 10 December 2024 | Toggle abstract · pdf

  Population genetics lies at the heart of evolutionary theory. This topic forms part of many biological science curricula but is rarely taught to physics students. Since physicists are becoming increasingly interested in biological evolution, we aim to provide a brief introduction to population genetics, written for physicists. We start with two background chapters: chapter 1 provides a brief historical introduction to the topic, while chapter 2 provides some essential biological background. We begin our main content with chapter 3 which discusses the key concepts behind Darwinian natural selection and Mendelian inheritance. Chapter 4 covers the basics of how variation is maintained in populations, while chapter 5 discusses mutation and selection. In chapter 6 we discuss stochastic effects in population genetics using the Wright-Fisher model as our example, and finally we offer concluding thoughts and references to textbooks in chapter 7.

• Dijet production at EIC and interplay of Sudakov and saturation effects in Weizsacker-Williams TMD gluon distribution

  Piotr Kotko

  SciPost Phys. Proc. 8, 020 (2022) · published 11 July 2022 | Toggle abstract · pdf

  We study production of dijets at the EIC using the small-x Improved Transverse Momentum Dependent factorization (ITMD), which is a framework based on the Color Glass Condensate theory. Dijet production in DIS is the simplest process directly coupled to the Weizsacker-Williams TMD gluon distribution, which is the only small-x gluon distribution possessing the gluon number density interpretation. We study various observables sensitive to the interplay of the Sudakov effects and the nonlinear effects, in particular the azimuthal correlations between the jet system and the scattered electron.