Publications

Order by: publication date number of citations

• An Ising model on a 3D honeycomb zigzag-ladder lattice: a solution to the ground-state problem

  Yuriy I. Dublenych, Oleg A. Petrenko

  SciPost Phys. Core 5, 047 (2022) · published 30 September 2022 | Toggle abstract · pdf

  A complex, seven-parameter ground-state problem for an Ising model on a 3D honeycomb zigzag-ladder lattice, containing two types of magnetic sites, is considered in the presence of an external field using the method of basic rays and basic sets of cluster configurations. It is shown that the geometrical frustration due to the presence of triangle elements leads to the emergence of a large variety of magnetic phases, the majority of which are highly degenerate. The obtained theoretical results are used to elucidate the sequence of phase transitions in the family of rare-earth oxides with a honeycomb zigzag-ladder lattice. New phases predicted by our model and observed experimentally do not appear in previously considered simpler models for noninteracting zigzag-ladders.

  1 citation

• Investigations of the few-nucleon systems within the LENPIC project

  Jacek Golak, Evgeny Epelbaum, Alessandro Grassi, Hiroyuki Kamada, Hermann Krebs, Patrick Reinert, Roman Skibiński, Volodymyr Soloviov, Kacper Topolnicki, Vitalii Urbanevych, Yuriy Volkotrub, Henryk Witała

  SciPost Phys. Proc. 3, 002 (2020) · published 24 February 2020 | Toggle abstract · pdf

  Results presented in this contribution are obtained within the Low Energy Nuclear Physics International Collaboration (LENPIC). LENPIC aims to develop chiral nucleon-nucleon and many-nucleon interactions complete through at least the fourth order in the chiral expansion. These interactions will be used together with consistently derived current operators to solve the structure and reactions of light and medium-mass nuclei including electroweak processes. In this contribution the current status of the chiral nuclear forces and current operators will be briefly discussed. A special role played by the calculations of nucleon-deuteron scattering will be explained.

  1 citation

• Magnetic properties of a multicomponent intermetallic compound Tb$_{0.25}$Dy$_{0.25}$Ho$_{0.25}$Er$_{0.25}$Al$_2$

  P. K. Jesla, Jeyaramane Arout Chelvane, R. Nirmala

  SciPost Phys. Proc. 11, 013 (2023) · published 6 June 2023 | Toggle abstract · pdf

  Polycrystalline multicomponent Laves phase rare earth intermetallic compound Tb$_{0.25}$ Dy$_{0.25}$Ho$_{0.25}$Er$_{0.25}$Al$_{2}$ has been synthesized by arc-melting and characterized by powder X-ray diffraction, magnetization and heat capacity measurements. The sample has MgCu$_2$-type cubic structure (space group Fd-3m) at 300 K. The compound Tb$_{0.25}$Dy$_{0.25}$Ho$_{0.25}$Er$_{0.25}$ Al$_{2}$ orders ferromagnetically at 50 K (T$_C$). This value is almost equal to the average of the ferromagnetic ordering temperatures of the individual RAl$_2$ (R = Tb, Dy, Ho and Er) compounds. Field dependence of magnetization below T$_C$ indicates soft-ferromagnetic nature. From the magnetization vs field data obtained near T$_C$ and the temperature dependence of heat capacity, low field magnetocaloric effect has been estimated.

  1 citation

• Codebase release r1.4 for CoVVVR

  Prasanth Shyamsundar, Jacob L. Scott, Stephen Mrenna, Konstantin T. Matchev, Kyoungchul Kong

  SciPost Phys. Codebases 28-r1.4 (2024) · published 4 March 2024 | Toggle abstract · src

  Monte Carlo (MC) integration is an important calculational technique in the physical sciences. Practical considerations require that the calculations are performed as accurately as possible for a given set of computational resources. To improve the accuracy of MC integration, a number of useful variance reduction algorithms have been developed, including importance sampling and control variates. In this work, we demonstrate how these two methods can be applied simultaneously, thus combining their benefits. We provide a python wrapper, named CoVVVR, which implements our approach in the VEGAS program. The improvements are quantified with several benchmark examples from the literature.

  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

• Variance reduction via simultaneous importance sampling and control variates techniques using vegas

  Prasanth Shyamsundar, Jacob L. Scott, Stephen Mrenna, Konstantin T. Matchev, Kyoungchul Kong

  SciPost Phys. Codebases 28 (2024) · published 4 March 2024 | Toggle abstract · pdf

  Monte Carlo (MC) integration is an important calculational technique in the physical sciences. Practical considerations require that the calculations are performed as accurately as possible for a given set of computational resources. To improve the accuracy of MC integration, a number of useful variance reduction algorithms have been developed, including importance sampling and control variates. In this work, we demonstrate how these two methods can be applied simultaneously, thus combining their benefits. We provide a python wrapper, named CoVVVR, which implements our approach in the VEGAS program. The improvements are quantified with several benchmark examples from the literature.

  1 citation

• Status of DUNE

  Alessandra Tonazzo on behalf of the DUNE Collaboration

  SciPost Phys. Proc. 1, 043 (2019) · published 21 February 2019 | Toggle abstract · pdf

  The Deep Underground Neutrino Experiment (DUNE) is a next-generation underground observatory, to be located in the USA, aiming at precise measurements of long-baseline neutrino oscillations over a 1300 km baseline, detection of supernova neutrinos and search for nucleon decay and other physics beyond the Standard Model. The far detector, a very large liquid argon time projection chamber, requires a dedicated prototyping effort (ProtoDUNE), currently ongoing at CERN.

  1 citation

• Exploring coherent elastic neutrino-nucleus scattering of reactor neutrinos with the NUCLEUS experiment

  C. Goupy, H. Abele, G. Angloher, A. Bento, L. Canonica, F. Cappella, L. Cardani, N. Casali, R. Cerulli, I. Colantoni, A. Cruciani, G. del Castello, M. del Gallo Roccagiovine, A. Doblhammer, S. Dorer, A. Erhart, M. Friendl, A. Garai, V. M. Ghete, D. Hauff, F. Jeanneau, E. Jericha, M. Kaznacheeva, A. Kinast, H. Kluck, A. Langenkämper, T. Lasserre, D. Lhuillier, M. Mancuso, B. Mauri, A. Mazzolari, E. Mazzucato, H. Neyrial, C. Nones, L. Oberauer, T. Ortmann, L. Pattavina, L. Peters, F. Petricca, W. Potzel, F. Pröbst, F. Pucci, F. Riendl, R. Rogly, M. Romagnoni, J. Rothe, N. Schermer, J. Schieck, S. Schönert, C. Schwertner, L. Scola, G. Soum Sidikov, L. Stodolsky, R. Strauss, M. Tamisari, C. Tomei, M. Vignati, M. Vivier, V. Wagner, A. Wex (The NUCLEUS collaboration)

  SciPost Phys. Proc. 12, 053 (2023) · published 5 July 2023 | Toggle abstract · pdf

  The NUCLEUS experiment aims to perform a high-precision measurement of Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) at the EdF Chooz B nuclear power plant in France. CEvNS is a unique process to study neutrino properties and to search for physics beyond the Standard Model. The study of CEvNS is also important for light Dark-Matter searches. It could be a possible irreducible background for high-sensitivity Dark-Matter experiments. NUCLEUS is an experiment under construction based on ultra-low threshold ($\sim$20 eV$_{nr}$) cryogenic calorimeters, operated at tens-of-mK temperatures.

  1 citation

• Cyclotron trap

  D. Gotta, L. M. Simons

  SciPost Phys. Proc. 5, 013 (2021) · published 6 September 2021 | Toggle abstract · pdf

  The cyclotron trap was developed at SIN/PSI to increase the stopping density of nega- tively charged particle beams for the formation of exotic atoms in low pressure gases. A weak focusing magnetic field, produced by superconducting solenoids, is used. Particles are injected radially through the fringe field to a moderator, which decelerates them into orbits bound by the field. Further deceleration by moderators and/or low-pressure gases leads the particles to the center of the device, where they can be stopped or eventually extracted. Experiments became feasible with this technique, such as those dealing with pionic hydrogen/deuteriumat SIN/PSI.Muonic hydrogen laser experiments also became possible with the extraction of muons from the cyclotron trap. The formation of antipro- tonic hydrogen in low pressure targets led to successful experiments at LEAR/CERN.

  1 citation

• Certifying quantum separability with adaptive polytopes

  Ties-A. Ohst, Xiao-Dong Yu, Otfried Gühne, H. Chau Nguyen

  SciPost Phys. 16, 063 (2024) · published 1 March 2024 | Toggle abstract · pdf

  The concept of entanglement and separability of quantum states is relevant for several fields in physics. Still, there is a lack of effective operational methods to characterise these features. We propose a method to certify quantum separability of two- and multiparticle quantum systems based on an adaptive polytope approximation. This leads to an algorithm which, for practical purposes, conclusively recognises two-particle separability for small and medium-size dimensions. For multiparticle systems, the approach allows to characterise full separability for up to five qubits or three qutrits; in addition, different classes of entanglement can be distinguished. Finally, our methods allow to identify systematically quantum states with interesting entanglement properties, such as maximally robust states which are separable for all bipartitions, but not fully separable.

  1 citation