Publications

Order by: publication date number of citations

• A brief tutorial on information theory

  Tarek Tohme, William Bialek

  SciPost Phys. Lect. Notes 87 (2024) · published 23 September 2024 | Toggle abstract · pdf

  At the 2023 Les Houches Summer School on Theoretical Biological Physics, several students asked for some background on information theory, and so we added a tutorial to the scheduled lectures. This is largely a transcript of that tutorial, lightly edited. It covers basic definitions and context rather than detailed calculations. We hope to have maintained the informality of the presentation, including exchanges with the students, while still being useful.

  1 citation

• Tangentially active polymers in cylindrical channels

  José Martín-Roca, Emanuele Locatelli, Valentino Bianco, Paolo Malgaretti, Chantal Valeriani

  SciPost Phys. 17, 107 (2024) · published 8 October 2024 | Toggle abstract · pdf

  We present an analytical and computational study characterizing the structural and dynamical properties of an active filament confined in cylindrical channels. We first outline the effects of the interplay between confinement and polar self-propulsion on the conformation of the chains. We observe that the scaling of the polymer size in the channel, quantified by the end-to-end distance, shows different anomalous behaviours under different confinement and activity conditions. In particular, we report scaling exponents that are markedly different from their passive counterparts. Interestingly, we show that the universal relation, describing the ratio between the end-to-end distance of passive polymer chains in cylindrical channels and in bulk is broken by activity. Finally, we show that the long-time diffusion coefficient under confinement can be rationalised by an analytical model, that takes into account the presence of the channel and the elongated nature of the polymer.

  1 citation

• Prospects for $\tau$ lepton physics at Belle II

  Michel Hernandez Villanueva on behalf of the Belle II collaboration

  SciPost Phys. Proc. 1, 003 (2019) · published 18 February 2019 | Toggle abstract · pdf

  The Belle II experiment is an upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+e^-$ collider. The accelerator has already successfully completed the first phase of commissioning and first electron positron-collisions in Belle II were observed in April 2018. The design luminosity of SuperKEKB is 8x10$^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than the Belle experiment. Belle II has a broad program of $\tau$ physics, in particular, precision measurements of Standard Model parameters and searches of lepton flavor and lepton number violations (LFV and LNV), benefiting from the large cross-section of the pairwise $\tau$ lepton production in $e^+e^-$ collisions. In this talk, we will review the $\tau$ lepton physics program of Belle II.

  1 citation

• A model for $F_L$ structure function at low values of $Q^2$ and $x$ - revisited

  Barbara Badelek, Anna Stasto

  SciPost Phys. Proc. 8, 082 (2022) · published 12 July 2022 | Toggle abstract · pdf

  A reanalysis of the model for the longitudinal structure function $F_L (x,Q^2)$ at low $x$ and low $Q^2$ was undertaken, in view of the advent of the EIC. The model includes the kinematic constraint $F_L\sim Q^4$ as $Q^2\rightarrow$ 0. It is based on the photon-gluon fusion mechanism suitably extrapolated to the region of low $Q^2$. Revised model was critically updated, extended to the EIC kinematic region, and e.g. contains new parameterisations of the parton distribution functions.

  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

• Downfolding the Su-Schrieffer-Heeger model

  Arne Schobert, Jan Berges, Tim Wehling, Erik van Loon

  SciPost Phys. 11, 079 (2021) · published 20 October 2021 | Toggle abstract · pdf

  Charge-density waves are responsible for symmetry-breaking displacements of atoms and concomitant changes in the electronic structure. Linear response theories, in particular density-functional perturbation theory, provide a way to study the effect of displacements on both the total energy and the electronic structure based on a single ab initio calculation. In downfolding approaches, the electronic system is reduced to a smaller number of bands, allowing for the incorporation of additional correlation and environmental effects on these bands. However, the physical contents of this downfolded model and its potential limitations are not always obvious. Here, we study the potential-energy landscape and electronic structure of the Su-Schrieffer-Heeger (SSH) model, where all relevant quantities can be evaluated analytically. We compare the exact results at arbitrary displacement with diagrammatic perturbation theory both in the full model and in a downfolded effective single-band model, which gives an instructive insight into the properties of downfolding. An exact reconstruction of the potential-energy landscape is possible in a downfolded model, which requires a dynamical electron-biphonon interaction. The dispersion of the bands upon atomic displacement is also found correctly, where the downfolded model by construction only captures spectral weight in the target space. In the SSH model, the electron-phonon coupling mechanism involves exclusively hybridization between the low- and high-energy bands and this limits the computational efficiency gain of downfolded models.

  1 citation

• Production of three isolated photons in the high-energy factorization approach

  Vladimir Saleev

  SciPost Phys. Proc. 8, 167 (2022) · published 14 July 2022 | Toggle abstract · pdf

  We study large-$p_T$ three-photon production at the LHC at the center-of-mass energy $\sqrt{s}=8$ TeV. We use the LO approximation of the parton Reggeization approach consistently merged with the real NLO corrections. For numerical calculations use the parton-level generator KaTie and modified KMR-type unintegrated parton distribution functions. We find good agreement between our predictions and data with the same accuracy as in the NNLO calculations based on the collinear parton model of QCD. At higher energies ($\sqrt{s}=13$ and 27 TeV) parton Reggeization approach predicts larger cross sections, up to $\sim 10$ \% and $\sim 20$ \%, respectively.

  1 citation

• Searches for new physics in collision events using a statistical technique for anomaly detection

  S. V. Chekanov

  SciPost Phys. Proc. 10, 015 (2022) · published 10 August 2022 | Toggle abstract · pdf

  This paper discusses a statistical anomaly-detection method for model-independent searches for new physics in collision events produced at the Large Hadron Collider (LHC). The method requires calculations of Z-scores for a large number of Lorenz-invariant variables to identify events that deviate from those expected for the Standard Model (SM).

  1 citation

• Higher spin swampland conjecture for massive AdS$_{3}$ gravity

  Rajae Sammani, El Hassan Saidi

  SciPost Phys. 18, 173 (2025) · published 3 June 2025 | Toggle abstract · pdf

  In this paper, we show that a possible version of the swampland weak gravity conjecture for higher spin (HS) massive topological AdS$_{3}$ gravity can be expressed in terms of mass M$_{\mathrm{hs}}$, charge Q$_{\mathrm{hs}}$ and coupling constant ${\large g}_{\mathrm{hs}}$ of 3D gravity coupled to higher spin fields as M$_{\mathrm{hs}}≤ \sqrt{2}$Q$_{\mathrm{hs}}{\large g}_{\mathrm{hs}}M_{\mathrm{Pl}}$. The higher spin charge is given by the $SO(1,2)$ quadratic Casimir Q$_{\mathrm{hs}}^{2}=s\left( s-1\right) $ and the HS coupling constant by ${\large g}_{\mathrm{hs}}^{2}=2/\left( M_{\mathrm{Pl}}^{2}l_{\mathrm{AdS}_{3}}^{2}\right) $ while the mass expressed like $\left( l_{\mathrm{AdS}_{3}}\text{M}_{\mathrm{hs}}\right) ^{2}$ is defined as $\left( 1+\mathrm{\mu }l_{\mathrm{AdS}_{3}}\right) ^{2}s\left( s-1\right) +\left[1-\left( \mathrm{\mu }l_{\mathrm{AdS}_{3}}\right) ^{2}\left( s-1\right) \right]$.

  1 citation

• Chiral symmetry restoration with three chiral partners

  Juan M. Torres-Rincon

  SciPost Phys. Proc. 6, 015 (2022) · published 31 May 2022 | Toggle abstract · pdf

  I discuss the masses of chiral partners in the context of chiral symmetry restoration at finite temperature. Using the Nambu–Jona-Lasinio model I first remind the usual situation where two mesons of opposed parity become degenerate above the chiral transition temperature. Then I consider an effective theory for D mesons where the positive parity companion presents a “double pole structure”. In this case three different masses need to be analyzed as functions of the temperature. I suggest a possible restoration pattern at high temperatures when the back-reaction of the quark condensate is incorporated.

  1 citation