Nuclear Theory·nucl-th

Wednesday·October 6, 2021

8 papers—4 primary·4 cross-listed

01
Calculations for nuclear matter and finite nuclei within and beyond energy--density--functional theories through interactions guided by effective field theory
C.J. Yang🇸🇪 · W.G. Jiang🇸🇪 · S. Burrello🇩🇪 · M. Grasso🇫🇷
We propose a novel idea to construct an effective interaction under energy-density-functional (EDF) theories which is adaptive to the enlargement of the model space. Guided by effective field theory principles, iterations of interactions as well as enlargements of the model space through particle-hole excitations are carried out for infinite nuclear matter and selected closed-shell nuclei ( $^{4}$ He, $^{16}$ O, $^{40}$ Ca, $^{56}$ Ni and $^{100}$ Sn) up to next-to-leading order. Our approach provides a new way for handling the nuclear matter and finite nuclei within the same scheme, with advantages from both EDF and ab initio approaches.
nucl-thPRC(2022)·6 citations
02
Analytic scattering parameters at low energies
Evgeny Z. Liverts
The scattering of two and more particles at low energies is described by the so called effective-range expansion. The leading terms of this expansion are the scattering length and effective range. The analytic expressions for both of the aforementioned scattering parameters are presented for the inverse-power potential and the Woods-Saxon potential. A technique for calculating the approximate scattering parameters is proposed. Approximate analytic formulas representing the scattering length and effective range are obtained for the Yukawa potential. The corresponding figures demonstrate a few interesting features of the effective range. All analytic formulas, both exact and approximate, were verified by comparing with the corresponding results obtained by direct numerical calculations. Wolfram Mathematica is heavily used. The presented results can be used with advantage in the fields of nuclear physics, atomic and molecular physics, quantum chemistry and many others.
nucl-thmath-phmath.MPphysics.atom-ph+21 citation
03
Jet-temperature anisotropy revealed through high- $p_{⊥}$ data
Stefan Stojku🇷🇸 · Jussi Auvinen🇷🇸 · Lidija Zivkovic🇷🇸 · Pasi Huovinen🇷🇸 · Magdalena Djordjevic🇷🇸
We explore to what extent, and how, high- $p_{⊥}$ data and predictions reflect the shape and anisotropy of the QCD medium formed in ultrarelativistic heavy-ion collisions. To this end, we use our recently developed DREENA-A framework, which can accommodate any temperature profile within the dynamical energy loss formalism. We show that the ratio of high- $p_{⊥}$ $v_{2}$ and $(1 - R_{AA})$ predictions reaches a well-defined saturation value, which is directly proportional to the time-averaged anisotropy of the evolving QGP, as seen by the jets.
nucl-thhep-phPLB(2022)·9 citations
04
Spectral density reconstruction with Chebyshev polynomials
Joanna E. Sobczyk🇩🇪 · Alessandro Roggero🇮🇹
Accurate calculations of the spectral density in a strongly correlated quantum many-body system are of fundamental importance to study its dynamics in the linear response regime. Typical examples are the calculation of inclusive and semi-exclusive scattering cross sections in atomic nuclei and transport properties of nuclear and neutron star matter. Integral transform techniques play an important role in accessing the spectral density in a variety of nuclear systems. However, their accuracy is in practice limited by the need to perform a numerical inversion which is often ill-conditioned. In the present work we extend a recently proposed quantum algorithm which circumvents this problem. We show how to perform controllable reconstructions of the spectral density over a finite energy resolution with rigorous error estimates. An appropriate expansion in Chebyshev polynomials allows for efficient simulations also on classical computers. We apply our idea to reconstruct a simple model -- response function as a proof of principle. This paves the way for future applications in nuclear and condensed matter physics.
nucl-thquant-phPRE(2022)·26 citations
05
Critical dynamics of relativistic diffusion
Dominik Schweitzer🇩🇪 · Sören Schlichting🇩🇪 · Lorenz von Smekal🇩🇪
We study the dynamics of self-interacting scalar fields with $Z_{2}$ symmetry governed by a relativistic Israel-Stuart type diffusion equation in the vicinity of a critical point. We calculate spectral functions of the order parameter in mean-field approximation as well as using first-principles classical-statistical lattice simulations in real-time. We observe that the spectral functions are well-described by single Breit-Wigner shapes. Away from criticality, the dispersion matches the expectations from the mean-field approach. At the critical point, the spectral functions largely keep their Breit-Wigner shape, albeit with non-trivial power-law dispersion relations. We extract the characteristic time-scales as well as the dynamic critical exponent $z$ , verifying the existence of a dynamic scaling regime. In addition, we derive the universal scaling functions implied by the Breit-Wigner shape with critical power-law dispersion and show that they match the data. Considering equations of motion for a system coupled to a heat bath as well as an isolated system, we perform this study for two different dynamic universality classes, both in two and three spatial dimensions.
↳ hep-latcond-mat.stat-mechhep-phnucl-thNPB(2022)·25 citations
06
Systematic study of hadronic excitation energy using Schottky anomaly
Harunobu Akiyama🇯🇵 · Daisuke Jido🇯🇵
We extract the excitation energy scales of the hadron spectra in a less model-dependent method using Schottky anomaly. Schottky anomaly is a thermodynamical phenomenon that the specific heat of a system consisting of a finite number of energy levels has a peak at finite temperature due to the energy gaps. Using the masses of all hadrons that are experimentally established, we obtain the excitation energy scales of the hadron spectra and investigate their flavor dependence.
↳ hep-phhep-exnucl-thPRD(2021)·1 citation
07
Peaks of sound velocity in two color dense QCD: quark saturation effects and semishort range correlations
Toru Kojo🇨🇳 · Daiki Suenaga🇯🇵
We discuss stiffening of dense matter in two color QCD (QC $_{2}$ D) where hadrons are mesons and diquark baryons. We study two models which describe a transition of matter from the Bose-Einstein-Condensation regime at low density to the Bardeen-Cooper-Schrieffer regime at high density. The first model is based on coherent states of diquarks, and the second is the Nambu-Jona-Lasinio model with diquark pairing terms. We particularly focus on how quark states are occupied as baryon density increases. We find that, due to the occupied quark levels, the ideal gas picture of diquarks breaks down at density significantly less than the density where baryon cores overlap. The saturation of quark states at low momenta stiffens equations of state. We also study the effects of interactions which depend on the quark occupation probability. We argue that equations of state become very stiff when the bulk part of the quark Fermi sea has the effective repulsion but the Fermi surface enjoys the attractive correlations. This disparity for different momentum domains is possible due to the strong channel dependence in gluon exchanges with momentum transfer of $0.2 - 1$ GeV. These concepts can be transferred from QC $_{2}$ D to QCD in any numbers of colors.
↳ hep-phastro-ph.HEhep-latnucl-thPRD(2022)·54 citations
08
A novel formulation of the unintegrated gluon distribution for DIS
Yacine Mehtar-Tani🇺🇸
In this talk, we revisit inclusive DIS in the small $x$ limit and derive a new factorization formula that accounts for leading powers in both Bjorken and Regge limits. In this semi-classical description, we obtain a new unintegrated gluon distribution which encompasses both the dipole operator and the gluon Parton Distribution Function with an explicit dependence on the longitudinal momentum fraction $x$ .
↳ hep-phnucl-thSciPost Phys.Proc.(2022)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE