Publications

Order by: publication date number of citations

• Majorana edge states in Kitaev chains of the BDI symmetry class

  Anton Bespalov

  SciPost Phys. Core 6, 080 (2023) · published 16 November 2023 | Toggle abstract · pdf

  Majorana edge states in Kitaev chains possessing an effective time reversal symmetry with one fermionic site per unit cell are studied. For a semi-infinite chain the equations for the wave functions of Majorana zero modes can be reduced to a single Wiener-Hopf equation, which has an exact analytical solution. We use this solution to determine the asymptotic behaviors of the Majorana wave functions at large distances from the edge of the chain for several infinite-range models described in the literature with focus on a model with slow power-law falloff of pairing and hopping amplitudes. For these models we also determine the asymptotic behavior of the energy of the fermionic state composed of two Majorana modes in the limit of long (finite) Kitaev chains.

  1 citation

• Double Virtual Contributions for Massless 2 -> 3 Scattering in NNLO QCD

  Vasily Sotnikov

  SciPost Phys. Proc. 7, 002 (2022) · published 20 June 2022 | Toggle abstract · pdf

  We review the recent advances in the calculation of two-loop QCD corrections for massless five-point scattering that paved the way for their broad phenomenological applications in calculation of NNLO QCD predictions. We first discuss the construction of a transcendental function basis which facilitates derivation of compact analytic representations for two-loop amplitudes and enables their fast and stable numerical evaluation over physical phase space. We then present the recent calculations of the leading-color two-loop corrections for hadroproduction of three photons and three jets.

  1 citation

• Zero modes and matching for the twist-3 PDFs

  Shohini Bhattacharya, Krzysztof Cichy, Martha Constantinou, Andreas Metz, Aurora Scapellato, Fernanda Steffens

  SciPost Phys. Proc. 8, 056 (2022) · published 12 July 2022 | Toggle abstract · pdf

  The quasi-PDF approach, proposed by X. Ji in 2013, has made it possible to directly extract light-cone PDFs from lattice QCD. This approach relies on the extraction of matrix elements of space-like operators for fast-moving hadrons. Quasi-PDFs can be related to the light-cone PDFs through a perturbatively calculable matching coefficient. We explore the formalism of matching, for the very first time, for the twist-3 PDFs $g_{T}(x)$, $e(x)$ and $h_{L}(x)$. In this work, we address the non-trivialities involved in the extraction of the matching coefficient due to the presence of (singular) zero-mode contributions.

  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

• Open strange meson $K^\pm_1$ in hot and dense nuclear matter

  Rajesh Kumar, Arvind Kumar

  SciPost Phys. Proc. 8, 055 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Using the unification of the chiral SU(3) model and QCD sum rules, we deduce the in-medium properties of $K^\pm_1$ meson. Within the chiral SU(3) model, medium modified gluon and quark condensates are evaluated through their interactions with the scalar fields ($\sigma$, $\zeta$, $\delta$, and $\chi$). These condensates are further used as input in the Borel transformed equations of QCD sum rules to evaluate the in-medium mass of strange $K^\pm_1$ meson. The in-medium property of the above meson can be used to study the restoration of chiral symmetry in nuclear matter.

  1 citation

• Measurement of Transverse Spin Dependent Azimuthal Correlations of Charged Pion(s) in $p^{\uparrow} p$ Collisions at $\sqrt s = 200$ GeV at STAR

  Babu R. Pokhrel

  SciPost Phys. Proc. 8, 047 (2022) · published 12 July 2022 | Toggle abstract · pdf

  At the leading twist, the transversity distribution function, $h^{q}_{1}(x)$, where $x$ is the longitudinal momentum fraction of the proton carried by quark $q$, encodes the transverse spin structure of the nucleon. Extraction of it is difficult because of its chiral-odd nature. In transversely polarized proton-proton collisions ($p^\uparrow p$), $h_{1}^{q}(x)$ can be coupled with another chiral-odd partner, a spin-dependent fragmentation function (FF). The resulting asymmetries in hadron(s) azimuthal correlations directly probe $h_{1}^{q}(x)$. We report the measurement of correlation asymmetries for charged pion(s) in $p^\uparrow p$, through the Collins and the Interference FF channel.

  1 citation

• Water tasting: A Bayesian multiverse analysis

  Suzanne Hoogeveen

  J. Robust. Rep. 0-Ex1 (2025) · published 16 April 2025 | Toggle abstract · pdf

  Varying data inclusion criteria and prior settings, a Bayesian multiverse analysis failed to provide robust evidence for the claim that people prefer Chaudfontaine over tap water.

  1 citation

• Thermodynamics of adiabatic quantum pumping in quantum dots

  Daniele Nello, Alessandro Silva

  SciPost Phys. Core 7, 067 (2024) · published 4 October 2024 | Toggle abstract · pdf

  We consider adiabatic quantum pumping through a resonant level model, a single-level quantum dot connected to two fermionic leads. Using the tools of adiabatic expansion, we develop a self-contained thermodynamic description of this model accounting for the variation of the energy level of the dot and the tunnelling rates with the thermal baths. This enables us to study various examples of pumping cycles computing the relevant thermodynamic quantities, such as the entropy produced and the dissipated power. These quantities are compared with the transport properties of the system, i.e. the pumped charge and the charge noise. Among other results, we find that the entropy production rate vanishes in the charge quantization limit while the dissipated power is quantized in the same limit.

  1 citation

• Kondo spectral functions at low-temperatures: A dynamical-exchange-correlation-field perspective

  Zhen Zhao

  SciPost Phys. 18, 002 (2025) · published 6 January 2025 | Toggle abstract · pdf

  We calculate the low-temperature spectral function of the symmetric single impurity Anderson model using a recently proposed dynamical exchange-correlation (xc) field formalism. The xc field, coupled to the one-particle Green's function, is obtained through analytic analysis and numerical extrapolation based on finite clusters. In the Kondo regime, the xc field is modeled by an Ansatz that takes into account the different asymptotic behaviors in the small- and large-time regimes. The small-time xc field contributes to the Hubbard side-band, whereas the large-time to the Kondo resonance. We illustrate these features in terms of analytical and numerical calculations for small- and medium-size finite clusters, and in the thermodynamic limit. The results indicate that the xc field formalism provides a good trade-off between accuracy and complexity in solving impurity problems. Consequently, it can significantly reduce the complexity of the many-body problem faced by first-principles approaches to strongly correlated materials.

  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