Nuclear Theory·nucl-th
6 papers—1 primary·5 cross-listed
[Submitted on 31 May 2024]
The appearance of wobbling motion and chirality in rotating triaxial nuclei is explained. The discovery of a new mode, chiral wobbling, in Br, is commented.
[Submitted on 30 May 2024] (cross-list from cond-mat.quant-gas)
Yicheng Zhang · Yuan Le · David S. Weiss · Marcos Rigol
We study the quantum evolution of one-dimensional Bose gases immediately after several variants of high-energy quenches, both theoretically and experimentally. Using the advantages conveyed by the relative simplicity of these nearly integrable many-body systems, we are able to differentiate the behaviors of two distinct but often temporally overlapping processes, hydrodynamization and local prethermalization. We show that the hydrodynamization epoch is itself characterized by two independent timescales, an oscillation period and an observable-dependent damping time. We also show how the existence of a hydrodynamization epoch depends on the exact nature of the high-energy quench. There is a universal character to our findings, which can be applied to the short-time behavior of any interacting many-body quantum system after a sudden high-energy quench. We specifically discuss its potential relevance to heavy-ion collisions.
[Submitted on 30 May 2024] (cross-list from hep-th)
Marcela Peláez🇺🇾 · Urko Reinosa🇫🇷 · Julien Serreau🇫🇷 · Matthieu Tissier🇫🇷 · Nicolás Wschebor🇺🇾
We revisit the non-Abelian dipole problem in the context of a simple semiclassical approach that incorporates some essential features of the infrared sector of Yang-Mills theories in the Landau gauge, in particular, the fact that both the running coupling and the gluon propagator remain finite at infrared scales and that the latter shows positivity violations that reflects the presence of massless modes. We obtain a simple flux tube solution in a controlled approximation scheme, which we compare to the results of lattice simulations.
[Submitted on 31 May 2024] (cross-list from astro-ph.HE)
Brendan T. Reed · Rahul Somasundaram · Soumi De · Cassandra L. Armstrong · Pablo Giuliani · Collin Capano · Duncan A. Brown · Ingo Tews
Gravitational-wave observations of binary neutron-star (BNS) mergers have the potential to revolutionize our understanding of the nuclear equation of state (EOS) and the fundamental interactions that determine its properties. However, Bayesian parameter estimation frameworks do not typically sample over microscopic nuclear-physics parameters that determine the EOS. One of the major hurdles in doing so is the computational cost involved in solving the neutron-star structure equations, known as the Tolman-Oppenheimer-Volkoff (TOV) equations. In this paper, we explore approaches to emulating solutions for the TOV equations: Multilayer Perceptrons (MLP), Gaussian Processes (GP), and a data-driven variant of the reduced basis method (RBM). We implement these emulators for three different parameterizations of the nuclear EOS, each with a different degree of complexity represented by the number of model parameters. We find that our MLP-based emulators are generally more accurate than the other two algorithms whereas the RBM results in the largest speedup with respect to the full, high-fidelity TOV solver. We employ these emulators for a simple parameter inference using a potentially loud BNS observation, and show that the posteriors predicted by our emulators are in excellent agreement with those obtained from the full TOV solver.
[Submitted on 31 May 2024] (cross-list from hep-lat)
Kei Iida🇯🇵 · Etsuko Itou🇯🇵 · Kotaro Murakami🇯🇵 · Daiki Suenaga🇯🇵
We investigate the phase structure and the equation of state (EoS) for dense two-color QCD (QCD) at low temperature ( MeV, lattice) for the purpose of extending our previous works~\cite{Iida:2019rah, Iida:2022hyy} at MeV ( lattice). Indeed, a rich phase structure below the pseudo-critical temperature as a function of quark chemical potential has been revealed, but finite volume effects in a high-density regime sometimes cause a wrong understanding. Therefore, it is important to investigate the temperature dependence down to zero temperature with large-volume simulations. By performing simulations, we obtain essentially similar results to the previous ones, but we are now allowed to get a fine understanding of the phase structure via the temperature dependence. Most importantly, we find that the hadronic-matter phase, which is composed of thermally excited hadrons, shrinks with decreasing temperature and that the diquark condensate scales as in the BCS phase, a property missing at MeV. From careful analyses, furthermore, we confirm a tentative conclusion that the topological susceptibility is independent of . We also show the temperature dependence of the pressure, internal energy, and sound velocity as a function of . The pressure increases around the hadronic-superfluid phase transition more rapidly at the lower temperature, while the temperature dependence of the sound velocity is invisible. Breaking of the conformal bound is also confirmed thanks to the smaller statistical error.
[Submitted on 31 May 2024] (cross-list from hep-ph)
In this study, we investigate photon-photon scattering in ultra-peripheral heavy ion collisions (UPCs). We start by deriving an effective Lagrangian from first principles and then apply factorization techniques from Soft-Collinear effective theory (SCET). This approach allows us to decompose the photon-photon scattering cross-section into two primary factors: the generalized transverse momentum distributions (GTMDs) and the hard scattering amplitude. We further analyze the emission of soft photons by final state leptons, incorporating a soft function into the cross section through an evolution method. Our analysis yields detailed predictions for observable angular correlations among the final state leptons. Specifically, we calculate the angular correlations characterized by the azimuthal parameters and , highlighting the influence of initial photons polarization and recoil effects from final state soft photons.
first authorsco-authorsvia INSPIRE