Publications

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• Generalized Gibbs ensembles in weakly interacting dissipative systems and digital quantum computers

  Iris Ulčakar, Zala Lenarčič

  SciPost Phys. 19, 068 (2025) · published 4 September 2025 | Toggle abstract · pdf

  Identifying use cases with superconducting circuits not critically affected by the inherent noise is a pertinent challenge. Here, we propose using a digital quantum computer to showcase the activation of integrable effects in weakly dissipative integrable systems. Dissipation is realized by coupling the system's qubits to ancillary ones that are periodically reset. We compare the digital reset protocol to the usual Lindblad continuous-time evolution by considering non-interacting integrable systems dynamics, which can be analyzed using scattering between the Bogoliubov quasiparticles caused by the dissipation. If not dominant, the inherent noise would cause extra scattering but would not critically change the physics. A corresponding quantum computer implementation would illuminate the possibilities of stabilizing exotic states in nearly integrable quantum materials.

  1 citation

• Shadow generalized parton distributions: a practical approach to the deconvolution problem of DVCS

  V. Bertone, H. Dutrieux, C. Mezrag, H. Moutarde, P. Sznajder

  SciPost Phys. Proc. 8, 107 (2022) · published 13 July 2022 | Toggle abstract · pdf

  Deeply virtual Compton scattering (DVCS) attracts a lot of interest due to its sensitivity to generalized parton distributions (GPDs) which provide a rich access to the partonic structure of hadrons. However, the practical extraction of GPDs for this channel requires a deconvolution procedure, whose feasibility has been disputed. We provide a practical approach to this problem based on a next-to-leading order analysis and a careful study of evolution effects, by exhibiting shadow GPDs with arbitrarily small imprints on DVCS observables at current and future experimental facilities. This shows that DVCS alone will not allow for a model independent extraction of GPDs and a multi-channel analysis is required for this purpose.

  1 citation

• MuCap: Muon Capture on the Proton

  Malte Hildebrandt, Claude Petitjean

  SciPost Phys. Proc. 5, 017 (2021) · published 6 September 2021 | Toggle abstract · pdf

  The singlet muon capture rate $\Lambda_S$ on the proton $\mu^-\ p \to \nu_\mu n$ is determined in a high precision lifetime measurement. The main apparatus consists of a new hydrogen time projection chamber as muon detector, developed by PSI, surrounded by cylindrical wire chambers and a plastic scintillator hodoscope as electron detectors. The parameter $\Lambda_S$ is evaluated as the difference between the inverse $\mu\,p$ lifetime and that of the free $\mu^+$. The result $\Lambda_S^\text{MuCap} = (715.6 \pm 5.4^\text{stat} \pm 5.1^\text{sys})\,\text{s}^{-1}$ is in excellent agreement with the prediction of chiral perturbation theory $\Lambda_S^{\chi\text{PT}} = (715.4 \pm 6.9)\,\text{s}^{-1}$. From $\Lambda_S^\text{MuCap}$ a recent analysis derives for the induced pseudoscalar coupling $g^\text{MuCap}_p = 8.23 \pm 0.83$ whereas $\bar{g}^{\chi\text{PT}}_p = 8.25 \pm 0.25$.}

  1 citation

• Probing lepton universality with (semi)-leptonic B decays

  Giovanni Banelli, Robert Fleischer, Ruben Jaarsma and Gilberto Tetlalmatzi-Xolocotzi

  SciPost Phys. Proc. 1, 013 (2019) · published 19 February 2019 | Toggle abstract · pdf

  The most recent measurements of the observables $R_{D^{(*)}}$ are in tension with the Standard Model offering hints of New Physics in $b\rightarrow c \ell \bar{\nu}_{\ell}$ transitions. Motivated by these results, in this work we present an analysis on their $b\rightarrow u \ell \bar{\nu}_{\ell}$ counterparts (for $\ell=e, ~\mu, ~\tau$). Our study has three main objectives. Firstly, using ratios of branching fractions, we assess the effects of beyond the Standard Model scalar and pseudoscalar particles in leptonic and semileptonic $B$ decays ($B^-\rightarrow \ell^- \bar{\nu}_{\ell}$, $\bar{B}\rightarrow \pi \ell \bar{\nu}_{\ell}$ and $\bar{B}\rightarrow \rho \ell \bar{\nu}_{\ell}$). Here a key role is played by the leptonic $B$ processes, which are highly sensitive to new pseudoscalar interactions. In particular, we take advantage of the most recent measurement of the branching fraction of the channel $B^-\rightarrow \mu^-\bar{\nu}_{\mu}$ by the Belle collaboration. Secondly, we extract the CKM matrix element $|V_{ub}|$ while accounting simultaneously for New Physics contributions. Finally, we provide predictions for the branching fractions of yet unmeasured leptonic and semileptonic $B$ decays.

  1 citation

• Algebraic structure of classical integrability for complex sine-Gordon

  Jean Avan, Luc Frappat, Eric Ragoucy

  SciPost Phys. 8, 033 (2020) · published 2 March 2020 | Toggle abstract · pdf

  The algebraic structure underlying the classical $r$-matrix formulation of the complex sine-Gordon model is fully elucidated. It is characterized by two matrices $a$ and $s$, components of the $r$ matrix as $r=a-s$. They obey a modified classical reflection/Yang--Baxter set of equations, further deformed by non-abelian dynamical shift terms along the dual Lie algebra $su(2)^*$. The sign shift pattern of this deformation has the signature of the twisted boundary dynamical algebra. Issues related to the quantization of this algebraic structure and the formulation of quantum complex sine-Gordon on those lines are introduced and discussed.

  1 citation

• A quantum annealing protocol to solve the nuclear shell model

  Emanuele Costa, Axel Pérez-Obiol, Javier Menéndez, Arnau Rios, Artur García-Sáez, Bruno Juliá-Díaz

  SciPost Phys. 19, 062 (2025) · published 29 August 2025 | Toggle abstract · pdf

  The nuclear shell model accurately describes the structure and dynamics of atomic nuclei. However, the exponential scaling of the basis size with the number of degrees of freedom hampers a direct numerical solution for heavy nuclei. In this work, we present a quantum annealing protocol to obtain nuclear ground states. We propose a tailored driver Hamiltonian that preserves a large gap and validate our approach in a dozen nuclei with basis sizes up to $10^5$ using classical simulations of the annealing evolution. We explore the relation between the spectral gap and the total time of the annealing protocol, assessing its accuracy by comparing the fidelity and energy relative error to classical benchmarks. While the nuclear Hamiltonian is non-local and thus challenging to implement in current setups, the estimated computational cost of our annealing protocol on quantum circuits is polynomial in the single-particle basis size, paving the way to study heavier nuclei.

  1 citation

• Codebase release r1.1 for SmoQyDEAC.jl

  James Neuhaus, Nathan S. Nichols, Debshikha Banerjee, Benjamin Cohen-Stead, Thomas A. Maier, Adrian Del Maestro, Steven Johnston

  SciPost Phys. Codebases 39-r1.1 (2024) · published 12 November 2024 | Toggle abstract · src

  We introduce the SmoQyDEAC.jl package, a Julia implementation of the Differential Evolution Analytic Continuation (DEAC) algorithm [N. S. Nichols et al., Phys. Rev. E 106, 025312 (2022)] for analytically continuing noisy imaginary time correlation functions to the real frequency axis. Our implementation supports fermionic and bosonic correlation functions on either the imaginary time or Matsubara frequency axes, and treatment of the covariance error in the input data. This paper presents an overview of the DEAC algorithm and the features implemented in the SmoQyDEAC.jl package. It also provides detailed benchmarks of the package's output against the popular maximum entropy and stochastic analytic continuation methods. The code for this package can be downloaded from our GitHub repository at https://github.com/SmoQySuite/SmoQyDEAC.jl or installed using the Julia package manager. The online documentation, including examples, can be accessed at https://smoqysuite.github.io/SmoQyDEAC.jl/stable/.

  1 citation

• Nuclear matter effects on jet production at electron-ion colliders

  Hai Tao Li, Ze Long Liu, Ivan Vitev

  SciPost Phys. Proc. 8, 134 (2022) · published 14 July 2022 | Toggle abstract · pdf

  In these proceedings we report recent progress on understanding hadron and jet production in electron-nucleus collisions at the future Electron-Ion Collider [1,2]. These processes will play an essential role in the exploration of the partonic structure of nuclei and the study of parton shower evolution in strongly-interacting matter. We employ the framework of soft-collinear effective theory, generalized to include in-medium interactions, to present the first theoretical results for inclusive hadron and jet cross sections, as well as the jet charge modification in deep inelastic scattering on nuclei. We further demonstrate how to separate initial-state and final-state effects.

  1 citation

• Codebase release 2.0 for UFOManager

  Mark S. Neubauer, Avik Roy, Zijun Wang

  SciPost Phys. Codebases 13-r2.0 (2023) · published 9 June 2023 | Toggle abstract · src

  Research in the data-intensive discipline of high energy physics (HEP) often relies on domain-specific digital contents. Reproducibility of research relies on proper preservation of these digital objects. This paper reflects on the interpretation of principles of Findability, Accessibility, Interoperability, and Reusability (FAIR) in such context and demonstrates its implementation by describing the development of an end-to-end support infrastructure for preserving and accessing Universal FeynRules Output (UFO) models guided by the FAIR principles. UFO models are custom-made python libraries used by the HEP community for Monte Carlo simulation of collider physics events. Our framework provides simple but robust tools to preserve and access the UFO models and corresponding metadata in accordance with the FAIR principles.

  1 citation

• TMD observables in unpolarised Semi-Inclusive DIS at COMPASS

  Andrea Moretti

  SciPost Phys. Proc. 8, 144 (2022) · published 14 July 2022 | Toggle abstract · pdf

  In 2016 and 2017, the COMPASS Collaboration at CERN collected a large sample of DIS events with a longitudinally polarised 160 GeV/$c$ muon beam scattering off a liquid hydrogen target. Part of the collected data has been analysed to extract preliminary results for the amplitudes of the modulations in the azimuthal angle of the charged hadrons and for their transverse-momentum distributions. These observables give relevant information for the study of the transverse momentum and spin structure of the nucleon. Similarly to the results obtained in COMPASS with a deuteron target, the azimuthal asymmetries exhibit interesting kinematic dependences, while the squared-transverse-momentum distributions can be described by two exponentials.

  1 citation