Publications

Order by: publication date number of citations

• Emergent symmetries in atomic nuclei: Probing nuclear dynamics and physics beyond the standard model

  Kristina D. Launey, K. S. Becker, G. H. Sargsyan, O. M. Molchanov, M. Burrows, A. Mercenne, T. Dytrych, D. Langr, J. P. Draayer

  SciPost Phys. Proc. 14, 007 (2023) · published 23 November 2023 | Toggle abstract · pdf

  Dominant shapes naturally emerge in atomic nuclei from first principles, thereby establishing the shape-preserving symplectic Sp(3, $\mathbb{R}$) symmetry as remarkably ubiquitous and almost perfect symmetry in nuclei. We discuss the critical role of this emergent symmetry in enabling machine-learning descriptions of heavy nuclei, ab initio modeling of $\alpha$ clustering and collectivity, as well as tests of beyond-the-standard-model physics. In addition, the Sp(3, $\mathbb{R}$) and SU(3) symmetries provide relevant degrees of freedom that underpin the ab initio symmetry-adapted no-core shell model with the remarkable capability of reaching nuclei and reaction fragments beyond the lightest and close-to-spherical species.

• Effect of next-nearest neighbor hopping on the single-particle excitations at finite temperature

  Harun Al Rashid, Dheeraj Kumar Singh

  SciPost Phys. 16, 107 (2024) · published 22 April 2024 | Toggle abstract · pdf

  In the half-filled one-orbital Hubbard model on a square lattice, we study the effect of next-nearest neighbor hopping on the single-particle spectral function at finite temperature using an exact-diagonalization + Monte-Carlo based approach to the simulation process. We find that the pseudogap-like dip, existing in the density of states in between the Néel temperature $T_N$ and a relatively higher temperature scale $T^*$, is accompanied with a significant asymmetry in the hole- and particle-excitation energy along the high-symmetry directions as well as along the normal-state Fermi surface. On moving from ($\pi/2, \pi/2$) toward $(\pi, 0)$ along the normal state Fermi surface, the hole-excitation energy increases, a behavior remarkably similar to what is observed in the $d$-wave state and pseudogap phase of high-$T_c$ cuprates, whereas the particle-excitation energy decreases. The quasiparticle peak height is the largest near ($\pi/2, \pi/2$) whereas it is the smallest near $(\pi, 0)$. These spectral features survive beyond $T_N$. The temperature window $T_N \lesssim T \lesssim T^*$ shrinks with an increase in the next-nearest neighbor hopping, which indicates that the next-nearest neighbor hopping may not be supportive to the pseudogap-like features.

• Impact of nuclear structure from shell model calculations on nuclear responses to WIMP elastic scattering for $^{19}$F and $^{nat}$Xe targets

  Raghda Abdel Khaleq, Cedric Simenel, Andrew E. Stuchbery

  SciPost Phys. Proc. 12, 062 (2023) · published 5 July 2023 | Toggle abstract · pdf

  Non-relativistic effective field theory (NREFT) is one approach used for describing the interaction of WIMPs with ordinary matter. Among other factors, these interactions are expected to be affected by the structure of the atomic nuclei in the target. The sensitivity of the nuclear response components of the WIMP-nucleus scattering amplitude is investigated using shell model calculations for $^{19}$F and $^{nat}$Xe. Resulting integrated nuclear response values are shown to be sensitive to some specifics of the nuclear structure calculations.

• 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.

• Computation of entanglement entropy in inhomogeneous free fermions chains by algebraic Bethe ansatz

  Pierre-Antoine Bernard, Gauvain Carcone, Nicolas Crampé, Luc Vinet

  SciPost Phys. Proc. 14, 018 (2023) · published 23 November 2023 | Toggle abstract · pdf

  The computation of the entanglement entropy for inhomogeneous free fermions chains based on $q$-Racah polynomials is considered. The eigenvalues of the truncated correlation matrix are obtained from the diagonalization of the associated Heun operator via the algebraic Bethe Ansatz. In the special case of chains based on dual $q$-Hahn polynomials, the eigenvectors and eigenvalues are expressed in terms of symmetric polynomials evaluated on the Bethe roots.

• Directional dark matter searches

  Elisabetta Baracchini

  SciPost Phys. Proc. 12, 002 (2023) · published 3 July 2023 | Toggle abstract · pdf

  The importance of directly detect and experimentally probe the nature of Dark Matter (DM) is universally and incontrovertibly recognised as one of the most compelling tasks of today's fundamental physics. Directional DM searches aim at developing experimental techniques that can give access to the measurement of the incoming direction of the DM particle. This can provide a correlation with an astrophysical source that no background whatsoever can mimic and offers an unique key for a positive, unambiguous identification of a DM signal.

• Recent results on Central Exclusive Production with the STAR detector

  Rafal Sikora

  SciPost Phys. Proc. 8, 087 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We present results on the Central Exclusive Production of charged particle pairs $h^{+}h^{-}$ ($h = \pi, K, p$), $pp\to p^\prime+h^{+}h^{-}+p^\prime$, obtained with the STAR experiment at RHIC in proton-proton collisions at a center-of-mass energy of $\sqrt{s} = 200$ GeV. All final-state particles were reconstructed, including forward-scattered protons detected in the Roman Pot system. As a result, the Double Pomeron Exchange (DPE) events were selected and the non-exclusive backgrounds were efficiently rejected. Differential fiducial cross sections were measured as functions of observables related to the central hadronic final state and to the forward-scattered protons. The measured cross sections were compared to phenomenological model predictions based on the DPE. We also present preliminary results on the measurement of the same physics process at higher collision energy $\sqrt{s} = 510$ GeV. The data demonstrate features similar to those observed at $\sqrt{s} = 200$ GeV.

• ATLAS LAr Calorimeter commissioning for LHC Run-3

  Luka Selem

  SciPost Phys. Proc. 8, 157 (2022) · published 14 July 2022 | Toggle abstract · pdf

  The ATLAS experiment at the Large Hadron Collider (LHC) measures proton--proton collisions at high energies. Within the Phase-I upgrade of the LHC before the start of Run-3 in 2022, the trigger system of the Liquid Argon calorimeter of ATLAS is being prepared to cope with an increased number of simultaneous proton--proton collisions. In the back-end of this new trigger system, the LATOME boards will be responsible for the computation of the energies deposited in the calorimeter. The commissioning of this computation within the LATOME is presented.

• 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.

• Strengthening the atom-field coupling through the deep-strong regime via pseudo-Hermitian Hamiltonians

  M. A. de Ponte, F. Oliveira Neto, P. M. Soares, M. H. Y. Moussa

  SciPost Phys. 15, 091 (2023) · published 13 September 2023 | Toggle abstract · pdf

  We present a strategy for strengthening the atom-field interaction through a pseudo-Hermitian Jaynes-Cummings Hamiltonian. Apart from the engineering of an effective non-Hermitian Hamiltonian, our strategy also relies on the accomplishment of short-time measurements on canonically conjugate variables. The resulting fast Rabi oscillations may be used for many quantum optics purposes and specially to shorten the processing time of quantum information.