Nuclear Theory·nucl-th

Wednesday·May 3, 2023

8 papers—4 primary·4 cross-listed

01
[Submitted on 2 May 2023]
Quantum information and quantum simulation of neutrino physics
A. B. Balantekin🇺🇸 · Michael J. Cervia🇺🇸 · Amol V. Patwardhan🇺🇸 · Ermal Rrapaj🇺🇸 · Pooja Siwach🇺🇸
In extreme astrophysical environments such as core-collapse supernovae and binary neutron star mergers, neutrinos play a major role in driving various dynamical and microphysical phenomena, such as baryonic matter outflows, the synthesis of heavy elements, and the supernova explosion mechanism itself. The interactions of neutrinos with matter in these environments are flavor-specific, which makes it of paramount importance to understand the flavor evolution of neutrinos. Flavor evolution in these environments can be a highly nontrivial problem thanks to a multitude of collective effects in flavor space, arising due to neutrino-neutrino ( $ν$ - $ν$ ) interactions in regions with high neutrino densities. A neutrino ensemble undergoing flavor oscillations under the influence of significant $ν$ - $ν$ interactions is somewhat analogous to a system of coupled spins with long-range interactions among themselves and with an external field ('long-range' in momentum-space in the case of neutrinos). As a result, it becomes pertinent to consider whether these interactions can give rise to significant quantum correlations among the interacting neutrinos, and whether these correlations have any consequences for the flavor evolution of the ensemble. In particular, one may seek to utilize concepts and tools from quantum information science and quantum computing to deepen our understanding of these phenomena. In this article, we attempt to summarize recent work in this field. Furthermore, we also present some new results in a three-flavor setting, considering complex initial states.
Comments:
13 pages, 3 figures. Invited review for the Eur. Phys. J. A special issue on "Quantum computing in low-energy nuclear theory"
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Quantum Physics (quant-ph)
arXiv:
2305.01150 [pdf]
EPJA(2023)·44 citations
02
[Submitted on 2 May 2023]
Properties of quark matter and hybrid stars from a quasiparticle model
He Liu🇨🇳 · Yong-Hang Yang🇨🇳 · Yue Han🇨🇳 · Peng-Cheng Chu🇨🇳
We investigate the properties of hybrid stars with the hadron-quark phase transition by using a quasiparticle model. Results from our study indicate that the coupling constant $g$ can stiffen the EOS of hybrid star matter and thus increase the hybrid star maximum mass and its tidal deformability, whereas it also decreases the mass and radius of the pure quark core. In addition, we find that a step change of the sound velocity occurs in the hadron-quark mixed phase, and it is restored with the decrease of nucleon and lepton degrees of freedom in the high density quark phase. The approximate rule that the polytropic index $γ \leq 1.75$ can also be used as a criterion for separating hadronic from quark matter in our work. The hypothesis of absolutely stable SQM (or "Witten hypothesis") suggests that a hybrid star containing a sufficient amount of SQM in its core will rapidly convert into a strange quark star. The SQM in hybrid stars therefore should break the absolutely stable condition, and the energy per nucleon ( $E / A$ ) of both $u d$ QM and SQM must exceed the lowest energy per nucleon 930 MeV. As a result, we provide the maximum mass, minimum radius $R_{1.4}$ and minimum tidal deformation $Λ_{1.4}$ of the hybrid stars as well as the maximum mass and radius of the quark matter core with different $g$ values within the allowable regions ( $E / A > 930$ MeV) on the $g - B^{1/4}$ plane. Using the constraints from astrophysical observations and heavy-ion experiments for comparison, our results indicate that the recently discovered massive neutron stars be well described as hybrid stars in the quasiparticle model, and confirm that the sizable quark-matter cores ( $R_{QC} > 6.5$ km) containing the mixed phase can appear in $2 M_{⊙}$ massive stars.
Comments:
10 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2305.01246 [pdf]
PRD(2023)·16 citations
03
[Submitted on 2 May 2023]
On-Shell Calculation of Mixed Electromagnetic and Gravitational Scattering
Barry R. Holstein🇺🇸
The study of long-range effects arising from the higher order exchange of massless particles via summation of Feynman diagrams is well known, but recently it has been shown that the use of on-shell methods can provide a streamlined route to the calculation of both electromagnetic and gravitational effects. In this note we demonstrate that the use of on-shell methods yields a similar simplification in the evaluation of higher order effects in the case of mixed electromagnetic and gravitational scattering.
Comments:
18 page Latex manuscript, 3 figures
Subjects:
Nuclear Theory (nucl-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2305.01426 [pdf]
PRD(2023)·3 citations
04
[Submitted on 2 May 2023]
Production of n-rich nuclei in red giant stars
Maurizio M. Busso · Sara Palmerini
We outline a partial historical summary of the steps through which the nucleosynthesis phenomena induced by {\it slow} neutron captures (the {\it s-process}) were clarified, a scientific achievement in which Franz Käppeler played a major role. We start by recalling the early phenomenological approach, which yielded a basic understanding of the subject even before models for the parent stellar evolutionary stages were developed. Through such a tool, rough limits for the neutron density and exposure were set, and the crucial fact was understood that more than one nucleosynthesis component is required to account for solar abundances of $s$ -process nuclei up to the Pb-Bi region. We then summarize the gradual understanding of the stellar processes actually involved in the production of nuclei from Sr to Pb (the so-called {\it Main Component}, achieved in the last decade of the past century and occurring in red giants of low and intermediate mass, ( $M ≲$ 8 $M_{⊙}$ ), populating, in the {\it HR} diagram, the {\it Asymptotic Giant Branch} or {\it AGB} region. We conclude by giving some details on more recent research concerning mixing mechanisms inducing the activation of the main neutron source, $^{13}$ C( $α$ ,n) $^{16}$ O.
Comments:
35 page, 8 figures
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2305.01549 [pdf]
EPJA(2023)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Quantum information and quantum simulation of neutrino physics

Properties of quark matter and hybrid stars from a quasiparticle model

On-Shell Calculation of Mixed Electromagnetic and Gravitational Scattering

Production of n-rich nuclei in red giant stars

Affiliations