Publications

Order by: publication date number of citations

• Search for light WIMP recoils on methane with NEWS-G

  Francisco A. Vazquez de Sola Fernandez on behalf of the NEWS-G collaboration

  SciPost Phys. Proc. 12, 073 (2024) · published 4 June 2024 | Toggle abstract · pdf

  The NEWS-G collaboration is searching for light dark matter using single-electron-threshold Spherical Proportional Counters (SPCs) filled with light gaseous targets (H, He, Ne). NEWS-G has built a new 140 cm diameter SPC equipped with a multi-anode ACHINOS sensor. Robust calibrations with a UV laser and an $\mathrm{^{37}}$Ar source were performed to characterize the detector response to low energy events and achieve statistical background rejection. This work presents preliminary results from physics data taken with methane, leading to world-leading spin-dependent sensitivity under 2 $\mathrm{GeV/c^{2}}$ WIMP masses.

  1 citation

• 2d dualities from 4d

  Jiaqun Jiang, Satoshi Nawata, Jiahao Zheng

  SciPost Phys. 18, 180 (2025) · published 6 June 2025 | Toggle abstract · pdf

  We find new $\mathcal{N}=(2,2)$ and $\mathcal{N}=(0,2)$ dualities through the twisted compactifications of 4d supersymmetric theories on $S^2$. Our findings include dualities for both $\mathcal{N}=(2,2)$ and $\mathcal{N}=(0,2)$ non-Abelian gauge theories, as well as $\mathcal{N}=(0,2)$ Gauge/Landau-Ginzburg duality.

  1 citation

• Central exclusive diffractive production of axial-vector $f_{1}$ mesons in proton-proton collisions

  Piotr Lebiedowicz, Josef Leutgeb, Otto Nachtmann, Anton Rebhan, Antoni Szczurek

  SciPost Phys. Proc. 8, 121 (2022) · published 13 July 2022 | Toggle abstract · pdf

  Exclusive production of axial-vector $f_{1}(1285)$ meson in proton-proton collisions via pomeron-pomeron fusion within the tensor-pomeron approach is discussed. Two ways to construct the pomeron-pomeron-$f_{1}$ coupling are presented. We adjust the parameters of our model to the WA102 experimental data and compare with predictions of the Sakai-Sugimoto model. Predictions for LHC experiments are given.

  1 citation

• Self-congruent point in critical matrix product states: An effective field theory for finite-entanglement scaling

  Jan T. Schneider, Atsushi Ueda, Yifan Liu, Andreas M. Läuchli, Masaki Oshikawa, Luca Tagliacozzo

  SciPost Phys. 18, 142 (2025) · published 29 April 2025 | Toggle abstract · pdf

  We set up an effective field theory formulation for the renormalization flow of matrix product states (MPS) with finite bond dimension, focusing on systems exhibiting finite-entanglement scaling close to a conformally invariant critical fixed point. We show that the finite MPS bond dimension $\chi$ is equivalent to introducing a perturbation by a relevant operator to the fixed-point Hamiltonian. The fingerprint of this mechanism is encoded in the $\chi$-independent universal transfer matrix's gap ratios, which are distinct from those predicted by the unperturbed Conformal Field Theory (CFT). This phenomenon defines a renormalization group self-congruent point, where the relevant coupling constant ceases to flow due to a balance of two effects; When increasing $\chi$, the infrared scale, set by the correlation length $\xi(\chi)$, increases, while the strength of the perturbation at the lattice scale decreases. The presence of a self-congruent point does not alter the validity of the finite-entanglement scaling hypothesis, since the self-congruent point is located at a finite distance from the critical fixed point, well inside the scaling regime of the CFT. We corroborate this framework with numerical evidence from the exact solution of the Ising model and density matrix renormalization group (DMRG) simulations of an effective lattice model.

  1 citation

• National Borders among Families: Removal and ‘Bare Life’ in India

  Salah Punathil

  Mig. Pol. 3, 005 (2024) · published 30 October 2024 | Toggle abstract · pdf

  This paper is about the state-driven process of ‘migrant ‘illegality’ (Genova 2002) and its impact on the life of Bengali speaking residents in the Assam state of India. While the movement of people across borders between India and present-day Bangladesh has been historical and complex, this ethnographic work explores how the state-driven process of migrant illegality and the production of ‘bare life’ have disrupted intimate relations and family life among this population in Assam. While the recent NRC (National Register of Citizens) update in Assam identified 1.9 million people as illegal migrants, there has been bureaucratic enactment of ‘migrant illegality’ by Assam Border Police for the last several years. The institutional procedures, court documents and narratives of the select cases of ‘detected’ as well as ‘detained’ migrants from ethnographic fieldwork reveal how the absence of formal papers and errors in the family records, kinship relations and property inheritance among the poor migrant families transforms actual citizens to ‘illegal migrants’ in the bureaucratic manoeuvring and reduces them to their ‘bare life’. The paper also shows how prejudice, arbitrariness, and contradictions feed into the bureaucratic process and lead to intense crises among family units, as several families have both Indians and alleged ‘Bangladeshis’ in their homes today. The paper argues that the major consequence of this state-driven ‘migrant illegality’ in the last two decades has been the creation of national borders among families, unsettling intimate relations and shared spaces.

  1 citation

• The resistance of quantum entanglement to temperature in the Kugel-Khomskii model

  Valerii E. Valiulin, Andrey V. Mikheyenkov, Nikolay M. Chtchelkatchev, Kliment I. Kugel

  SciPost Phys. Core 6, 025 (2023) · published 4 April 2023 | Toggle abstract · pdf

  The Kugel-Khomskii model with entangled spin and orbital degrees of freedom is a good testing ground for many important features in quantum information processing, such as robust gaps in the entanglement spectra. Here, we demonstrate that the entanglement can be also robust under effect of temperature within a wide range of parameters. It is shown, in particular, that the temperature dependence of entanglement often exhibits a nonmonotonic behavior. Namely, there turn out to be ranges of the model parameters, where entanglement is absent at zero temperature, but then, with an increase in temperature, it appears, passes through a maximum, and again vanishes.

  1 citation

• A tale of $Z$+jet: SMEFT effects and the Lam-Tung relation

  Rhorry Gauld, Ulrich Haisch, Joachim Weiss

  SciPost Phys. 18, 148 (2025) · published 6 May 2025 | Toggle abstract · pdf

  We derive constraints on dimension-six light-quark dipole operators within the Standard Model (SM) effective field theory, based on measurements of $Z$ production at SLC and LEP, as well as $Z$+jet production at the LHC. Our new constraints exclude the parameter space that could potentially explain the observed discrepancy between theoretical predictions and experimental data for the Lam-Tung relation. With these updated limits, we model-independently determine the maximum possible influence that beyond-SM contributions could have on the angular coefficients $A_0$ and $A_2$, which enter the Lam-Tung relation.

  1 citation

• A real-time approach to frequency-mixing spectroscopies: Application to sum and difference frequency generation in two-dimensional crystals

  Mike N. Pionteck, Myrta Grüning, Simone Sanna, Claudio Attaccalite

  SciPost Phys. 19, 129 (2025) · published 18 November 2025 | Toggle abstract · pdf

  We propose a computational framework to extract nonlinear response functions from real-time simulations in the presence of more than one external field. We apply this approach to the calculation of sum frequency generation (SFG) and difference frequency generation (DFG). SFG and DFG are second-order nonlinear processes where two lasers with frequencies $\omega_1$ and $\omega_2$ combine to produce a response at frequency $\omega = \omega_1 ± \omega_2$. Compared with other nonlinear responses such as second-harmonic generation, SFG and DFG allow for tunability over a larger range. Moreover, the optical response can be enhanced by selecting the two laser frequencies in order to match specific electron-hole transitions. To assess the approach, we calculate the SFG and DFG of two-dimensional crystals, h-BN and MoS$_2$ monolayers, from real-time solution of an effective Schrödinger equation. Within the effective Schrödinger equation, one can select from various levels of theory for the effective one-particle Hamiltonian to account for local-field effects and electron-hole interactions. We compare results obtained within the independent particle picture and including many-body effects. Such comparison allows us to identify and characterize excitonic features in the obtained spectra. Additionally, we demonstrate that our approach can also extract higher-order response functions, such as field-induced second-harmonic generation. We provide an example using the h-BN bilayer.

  1 citation

• Measurements of the Antiquark Flavor Asymmetry in the Proton by the Drell-Yan Experiment SeaQuest

  Kei Nagai

  SciPost Phys. Proc. 8, 119 (2022) · published 13 July 2022 | Toggle abstract · pdf

  The antiquark flavor asymmetry dbar/ubar in the proton gives an insight on the non-perturbative structure of the proton. The SeaQuest experiment measured the Drell–Yan cross section ratio of proton-deuterium to proton-proton to determine the antiquark flavor asymmetry dbar/ubar precisely in the range of 0.13<x<0.45. SeaQuest provides the evidence of dbar/ubar > 1.0 over a wide range of momenta. Some theoretical models reproduce this result.

  1 citation

• The ALF (Algorithms for Lattice Fermions) project release 2.4. Documentation for the auxiliary-field quantum Monte Carlo code

  F. F. Assaad, M. Bercx, F. Goth, A. Götz, J. S. Hofmann, E. Huffman, Z. Liu, F. Parisen Toldin, J. S. E. Portela, J. Schwab

  SciPost Phys. Codebases 1-v2.4 (2025) · published 27 November 2025 · licensed under CC BY-SA (4.0) | Toggle abstract · pdf

  The Algorithms for Lattice Fermions package provides a general code for the finite-temperature and projective auxiliary-field quantum Monte Carlo algorithm. The code is engineered to be able to simulate any model that can be written in terms of sums of single-body operators, of squares of single-body operators and single-body operators coupled to a bosonic field with given dynamics. The package includes five pre-defined model classes: SU(N) Kondo, SU(N) Hubbard, SU(N) t-V and SU(N) models with long range Coulomb repulsion on honeycomb, square and N-leg lattices, as well as $Z_2$ unconstrained lattice gauge theories coupled to fermionic and $Z_2$ matter. An implementation of the stochastic Maximum Entropy method is also provided. One can download the code from our Git instance at https://git.physik.uni-wuerzburg.de/ALF/ALF/-/tree/ALF-2.4 and sign in to file issues.

  1 citation