Nuclear Theory·nucl-th

Wednesday·November 8, 2023

10 papers—6 primary·4 cross-listed

01
Chiral catalysis of nuclear fusion in molecules
Dmitri E. Kharzeev · Jake Levitt
At low energies, nuclear fusion is strongly affected by electron screening of the Coulomb repulsion among the fusing nuclei. It may thus be possible to catalyze nuclear fusion in molecules (i.e., to fuse specific nuclei in situ) through quantum control of electron wave functions in intense laser fields. The circularly polarized (chiral) laser field can effectively squeeze the electron wave functions, greatly enhancing the screening in the spatial region relevant for the fusion process. We estimate the corresponding fusion probabilities, and find that the proposed chiral catalysis of nuclear fusion in molecules may be observable, potentially with important practical applications.
nucl-thhep-phIJMPE(2024)·1 citation
02
Describing the Thermal Radiation in $A u + A u$ Collisions at $s_{N N} =$ 200 GeV by an Analytic Solution of Relativistic Hydrodynamics
Gábor Kasza🇭🇺
In high-energy heavy-ion collisions a nearly perfect fluid, the so-called strongly coupled quark gluon plasma forms. After the short period of thermalisation, the evolution of this medium can be described by the laws of relativistic hydrodynamics. The time evolution of the quark gluon plasma can be understood through direct photon spectra measurements, which are sensitive to the entire period between the thermalisation and the freeze-out of the medium. I present a new analytic formula that describes the thermal photon radiation and it is derived from an exact and finite solution of relativistic hydrodynamics with accelerating velocity field. Then I compare my calculations to the most recent nonprompt spectrum of direct photons for $A u + A u$ at $s_{N N} =$ 200 GeV collisions. I have found a convincing agreement between the model and the data, which allows to give an estimate of the initial temperature in the center of the fireball. My results predict hydrodynamic scaling behaviour for the thermal photon spectra of high-energy heavy-ion collisions.
nucl-thhep-phInt.J.Mod.Phys.A(2024)·4 citations
03
Odd nuclei and quasiparticle excitations within the Barcelona Catania Paris Madrid energy density functional
S.A. Giuliani · L.M. Robledo
An extension of the Barcelona Catania Paris Madrid (BCPM) energy density functional is proposed to deal with odd-mass systems as well as multiquasiparticle excitations. The extension is based on the assumption that the equal filling approximation (EFA) is a valid alternative to the traditional full blocking procedure of the Hartree-Fock-Bogoliubov method. The assumption is supported by the excellent agreement between full blocking and EFA calculations obtained with different parametrizations of the Gogny interaction. The EFA augmented BCPM functional is used to compute low energy excitation spectra of selected nuclei in different regions of the nuclear chart, and high- $K$ isomers in $^{178}$ Hf. We show that BCPM predictions are in good agreement with Gogny D1M results and experimental data.
nucl-thPRC(2024)·3 citations
04
Estimate magnetic field strength in heavy-ion collisions via the direct photon elliptic flow
Jing-An Sun🇨🇳 · Li Yan🇨🇳
There must be electromagnetic fields created during high-energy heavy-ion collisions. As the quark-gluon plasma (QGP) starts to evolve hydrodynamically, although these fields may become weak comparing to the energy scales of the strong interaction, they are potentially important to some electromagnetic probes. In this work, we focus on the dissipative corrections in QGP due to the presence of a weak external magnetic field, and calculate accordingly the induced photon radiation in the framework of viscous hydrodynamics. By event-by-event hydrodynamical simulations, the experimentally measured direct photon elliptic flow can be well reproduced. Correspondingly, the direct photon elliptic flow implies a magnetic field strength around 0.1 $m_{π}^{2} \sim 1 0^{16}$ G. This is indeed a weak field in heavy-ion physics that is compatible to the theoretical predictions, however, it is still an ultra-strong magnetic field in nature.
nucl-thhep-phnucl-exPRC(2024)·20 citations
05
Algebraic solutions for $o (12) \leftrightarrow u (2) \otimes u (10)$ quantum phase transitions in the proton-neutron interacting boson model
M. M. Hammad · Andriana Martinou · Dennis Bonatsos
A simple systematic procedure to construct the proton-neutron unitary, $u_{sd}^{π ν} (12)$ , orthogonal, $o_{sd}^{π ν} (12)$ , and quasi-spin $su_{sd}^{π ν} (1, 1)$ algebras of the sd bosonic system is presented. New algebraic substructures of these algebras are discussed and the explicit formulae for their generators and Casimir operators are given in the spherical tensor form. The complementarity relationship of the Casimir operators of the $su_{sd}^{π ν} (1, 1)$ and $o_{sd}^{π ν} (12)$ is derived. The exact algebraic solutions of the quantum phase transition Hamiltonian between the $o_{sd}^{π ν} (12)$ and $u_{s}^{π ν} (2) \otimes u_{d}^{π ν} (10)$ limits has been considered, for the first time, in the framework of affine $su_{sd}^{π ν} (1, 1)$ Lie algebra. The low lying energy spectra of the $^{70} Ge,^{76 - 78} Se,^{96 - 98} Mo, and^{100 - 102} Ru$ isotopes are calculated using the $o_{sd}^{π ν} (12) \leftrightarrow u_{s}^{π ν} (2) \otimes u_{d}^{π ν} (10)$ transition Hamiltonian. The good agreement of our computation with empirical result in these isotopes emphasizes the importance of $u_{s}^{π ν} (2) \otimes u_{d}^{π ν} (10)$ limit. With this addition, symmetry can be extended to many nuclei.
nucl-thNPA(2022)·1 citation
06
An extended Skyrme momentum dependent potential in asymmetric nuclear matter and transport models
Junping Yang🇨🇳 · Xiang Chen🇨🇳 · Ying Cui🇨🇳 · Yangyang Liu🇨🇳 · Zhuxia Li🇨🇳 · Yingxun Zhang🇨🇳
Based on an extended Skyrme momentum-dependent interaction (MDI), we derive an isospin asymmetric equation of state, isospin-dependent single-particle potential and the Hamiltonian which can be used in the Boltzmann-Uehling-Uhlenbeck (BUU) model and the quantum molecular dynamics (QMD) model at the beam energy less than 1 GeV/u. As an example of the applications of extended Skyrme MDI, we also present the results obtained with the extended Skyrme momentum-dependent interaction in the improved quantum molecular dynamics model (ImQMD), and the influence of the effective mass splitting on the isospin sensitive observables, i.e., the single and double neutron-to-proton ratios, is discussed again.
nucl-thnucl-exPRC(2024)·9 citations
07
The Weakly Bound States in Gaussian Wells: From the Binding Energy of Deuteron to the Electronic Structure of Quantum Dots
G. Rodriguez-Espejo · J. Segura-Landa · J. Ortiz-Monfil · D. J. Nader
Gaussian potentials serve as a valuable tool for the comprehensive modeling of short-range interactions, spanning applications from nuclear physics to the artificial confinement of electrons within quantum dots. This study focuses on examining the lowest states within Gaussian wells, with particular emphasis on the weakly bound regime. The analysis delves into the asymptotic behavior of the exact wave function at both small and large distances, motivating the development of a few-parametric Ansatz which is locally accurate and yields to a fast convergent basis set. To validate its efficacy, we assess its convergence rate using a toy model of Nuclear Physics, specifically for Deuteron. Furthermore, we employ the expansion of the energy close to the threshold to derive an analytical formula for the binding energy of the deuteron whose accuracy improves as the effective parameter approaches the critical. In concluding our investigation, we evaluate the performance of our Ansatz as an orbital in the exploration of the electronic structure of a two-electron quantum dot.
↳ quant-phnucl-thInt.J.Quant.Chem.(2024)·0 citations
08
Universal features of $2 \to N$ scattering in QCD and gravity from shockwave collisions
Himanshu Raj🇫🇷 · Raju Venugopalan🇺🇸
A remarkable double copy relation of Einstein gravity to QCD in Regge asymptotics is $Γ^{μν} = \frac{1}{2} C^{μ} C^{ν} - \frac{1}{2} N^{μ} N^{ν}$ , where $Γ^{μν}$ is the gravitational Lipatov vertex in the $2 \to 3$ graviton scattering amplitude, $C^{μ}$ its Yang-Mills counterpart, and $N^{μ}$ the QED bremssstrahlung vertex. In QCD, the Lipatov vertex is a fundamental building block of the BFKL equation describing $2 \to N$ scattering of gluons at high energies. Likewise, the gravitational Lipatov vertex is a key ingredient in a 2-D effective field theory framework describing trans-Planckian $2 \to N$ graviton scattering. We construct a quantitative correspondence between a semi-classical Yang-Mills framework for radiation in gluon shockwave collisions and its counterpart in general relativity. In particular, we demonstrate the Lipatov double copy in a dilute-dilute approximation corresponding to $R_{S, L}$ , $R_{S, H}$ $≪ b$ , with $R_{S, L}$ , $R_{S, H}$ the respective emergent Schwarzchild radii generated in shockwave collisions and $b$ is the impact parameter. We outline extensions of the correspondence developed here to the dilute-dense computation of gravitational wave radiation in close vicinity of one of the black holes, the construction of graviton propagators in the shockwave background, and a renormalization group approach to compute $2 \to N$ amplitudes that incorporates graviton reggeization and coherent graviton multiple scattering.
↳ hep-thgr-qchep-phnucl-thPRD(2024)·14 citations
09
Chiral Soliton Lattice turns into 3D crystal
Geraint W. Evans🇹🇼 · Andreas Schmitt🇬🇧
Chiral perturbation theory predicts the chiral anomaly to induce a so-called Chiral Soliton Lattice at sufficiently large magnetic fields and baryon chemical potentials. This state breaks translational invariance in the direction of the magnetic field and was shown to be unstable with respect to charged pion condensation. Improving on previous work by considering a realistic pion mass, we employ methods from type-II superconductivity and construct a three-dimensional pion (and baryon) crystal perturbatively, close to the instability curve of the Chiral Soliton Lattice. We find an analogue of the usual type-I/type-II transition in superconductivity: Along the instability curve for magnetic fields $e B > 0.12 GeV^{2}$ and chemical potentials $μ < 910 MeV$ , this crystal can continuously supersede the Chiral Soliton Lattice. For smaller magnetic fields the instability curve must be preceded by a discontinuous transition.
↳ hep-thhep-phnucl-thJHEP(2024)·24 citations
10
Elastic and resonance structures of the nucleon from hadronic tensor in lattice QCD: implications for neutrino-nucleon scattering and hadron physics
Jian Liang🇨🇳 · Raza Sabbir Sufian🇺🇸 · Bigeng Wang🇺🇸 · Terrence Draper🇺🇸 · Tanjib Khan🇧🇩 · Keh-Fei Liu🇺🇸 · Yi-Bo Yang🇨🇳 · Christian Zimmermann🇺🇸
We compute the Euclidean hadronic tensor from charge density operators and extract elastic and resonance structures by employing exponential fits to the four-point correlator, as well as a Bayesian reconstruction inverse algorithm to obtain the corresponding spectral density for qualitative comparison. We present the determination of the nucleon's Sachs electric form factor using the hadronic tensor formalism and verify that it is consistent with that from the conventional three-point function calculation. Beyond the elastic peak, we observe a structure located approximately $0.5 - 0.7$ GeV above the nucleon mass in the Bayesian reconstruction. The structure is interpreted as a mixture of the Roper resonance $(N (1440))$ , and states with both positive and negative parities in this mass region, as well as multi-hadron states. Assuming the observed structure is dominated by $J^{P} = 1/ 2^{\pm}$ states, we extract the transition electric form factor $G_{E}^{*} (Q^{2})$ and the corresponding longitudinal helicity amplitude $S_{1/2} (Q^{2})$ , and compare them with those determined from the CLAS experimental data of nucleon-to-Roper transition. Although fitting to the four-point correlation function or using the inverse algorithm does not resolve individual resonances, it nevertheless enables the determination of total inclusive lepton-nucleon scattering cross sections in appropriate energy bins. This lattice QCD calculation presents the first major step toward studying the inclusive $N \to X$ contributions with the hadronic tensor formalism.
↳ hep-lathep-phnucl-thPRD(2026)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE