Nuclear Theory·nucl-th

Tuesday·September 24, 2019

14 papers—7 primary·7 cross-listed

08
[Submitted on 21 Sept 2019] (cross-list from quant-ph)
Analytic solutions of the Schrödinger equation with non-central generalized inverse quadratic Yukawa potential
C. O. Edet · P. O Okoi · S. O Chima
This study presents the solutions of Schrödinger equation for the Non-Central Generalized Inverse Quadratic Yukawa Potential within the framework of Nikiforov-Uvarov. The radial and angular part of the Schrödinger equation are obtained using the method of variable separation. More so, the bound states energy eigenvalues and corresponding eigenfunctions are obtained analytically. Numerical results were obtained for the Generalized Inverse Quadratic Yukawa Potential for comparison sake. It was found out that our results agree with existing literature.
Comments:
17 pages, 1 figure, accepted for publication in Revista Brasileira de Ensino de Física
Subjects:
Quantum Physics (quant-ph); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
1909.09820 [pdf]
Rev.Bras.Ens.Fis.(2020)·13 citations
09
[Submitted on 21 Sept 2019] (cross-list from hep-ph)
Temperature Dependence of the Axion Mass in a Scenario Where the Restoration of Chiral Symmetry Drives the Restoration of the $U_{A} (1)$ Symmetry
Davor Horvatić🇭🇷 · Dalibor Kekez🇭🇷 · Dubravko Klabučar🇭🇷
The temperature ( $T$ ) dependence of the axion mass is predicted for $T$ 's up to $\sim 2.3 \times$ the chiral restoration temperature of QCD. The axion is related to the $U_{A} (1)$ anomaly. The squared axion mass $m_{a} (T)^{2}$ is, modulo the presently undetermined scale of spontaneous breaking of Peccei-Quinn symmetry $f_{a}$ (squared), equal to QCD topological susceptibility $χ (T)$ for all $T$ . We obtain $χ (T)$ by using quark condensates calculated in two effective Dyson-Schwinger models of nonperturbative QCD. They exhibit the correct chiral behavior, including the dynamical breaking of chiral symmetry and its restoration at high $T$ . This is reflected in the $U_{A} (1)$ symmetry breaking and restoration through $χ (T)$ . In our previous studies, such $χ (T)$ yields the $T$ -dependence of the $U_{A} (1)$ -anomaly-influenced masses of $η^{'}$ and $η$ mesons consistent with experiment. This in turn supports our prediction for the $T$ -dependence of the axion mass. Another support is a rather good agreement with the pertinent lattice results. This agreement is not spoiled by our varying $u$ and $d$ quark mass parameters out of the isospin limit.
Comments:
23 pages, 7 figures, title changed, references added, minor style and language changes, version published in Universe 5 (2019) no.10, 208,
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1909.09879 [pdf]
Universe(2019)·8 citations
10
[Submitted on 23 Sept 2019] (cross-list from hep-ph)
Towards a combined analysis of inclusive/exclusive electroproduction
Astrid N. Hiller Blin🇩🇪 · Vitaly V. Chesnokov🇷🇺 · Victor I. Mokeev🇺🇸
In view of the major advances achieved by the CLAS experiments in studying the N* electroexcitation amplitudes, as well as further extension of these studies in the experiments with CLAS12, we present an approach for the evaluation of the resonant contributions to inclusive electron scattering off protons. For the first time, the resonant contributions are determined from the experimental results on N* electrocouplings available from the data analyses of exclusive meson electroproduction off protons. This is a useful benchmark for future endeavours on understanding the transition region between low and high-energy regions, strongly related to tests on quark-hadron duality.
Comments:
NSTAR2019 conference proceedings
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1909.10183 [pdf]
EPJ Web Conf.(2020)·1 citation
11
[Submitted on 23 Sept 2019] (cross-list from quant-ph)
The Hellmann-Feynman theorem at finite temperature
Marina Pons · Bruno Juliá-Díaz · Arnau Rios · Isaac Vidaña · Artur Polls
We present a simple derivation of the Hellmann-Feynman theorem at finite temperature. We illustrate its validity by considering three relevant examples which can be used in quantum mechanics lectures: the one-dimensional harmonic oscillator, the one-dimensional Ising model and the Lipkin model. We show that the Hellmann-Feynman theorem allows one to calculate expectation values of operators that appear in the Hamiltonian. This is particularly useful when the total free-energy is available, but there is not direct access to the thermal average of the operators themselves.
Comments:
8 pages, 3 figures. Updated version, accepted in American Journal of Physics
Subjects:
Quantum Physics (quant-ph); Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th); physics.ed-ph (physics.ed-ph)
arXiv:
1909.10298 [pdf]
Am.J.Phys.(2020)·5 citations
12
[Submitted on 23 Sept 2019] (cross-list from hep-lat)
Consistency checks for two-body finite-volume matrix elements: I. Conserved currents and bound states
Raúl A. Briceño🇺🇸 · Maxwell T. Hansen🇨🇭 · Andrew W. Jackura🇺🇸
Recently, a framework has been developed to study form factors of two-hadron states probed by an external current. The method is based on relating finite-volume matrix elements, computed using numerical lattice QCD, to the corresponding infinite-volume observables. As the formalism is complicated, it is important to provide non-trivial checks on the final results and also to explore limiting cases in which more straightforward predications may be extracted. In this work we provide examples on both fronts. First, we show that, in the case of a conserved vector current, the formalism ensures that the finite-volume matrix element of the conserved charge is volume-independent and equal to the total charge of the two-particle state. Second, we study the implications for a two-particle bound state. We demonstrate that the infinite-volume limit reproduces the expected matrix element and derive the leading finite-volume corrections to this result for a scalar current. Finally, we provide numerical estimates for the expected size of volume effects in future lattice QCD calculations of the deuteron's scalar charge. We find that these effects completely dominate the infinite-volume result for realistic lattice volumes and that applying the present formalism, to analytically remove an infinite-series of leading volume corrections, is crucial to reliably extract the infinite-volume charge of the state.
Comments:
20 pages, 5 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1909.10357 [pdf]
PRD(2019)·39 citations
13
[Submitted on 23 Sept 2019] (cross-list from quant-ph)
A new approach for open quantum systems based on a phonon number representation of a harmonic oscillator bath
M. Tokieda · K. Hagino
To investigate a system coupled to a harmonic oscillator bath, we propose a new approach based on a phonon number representation of the bath. Compared to the method of the hierarchical equations of motion, the new approach is computationally much less expensive in a sense that a reduced density matrix is obtained by calculating the time evolution of vectors, instead of matrices, which enables one to deal with large dimensional systems. As a benchmark test, we consider a quantum damped harmonic oscillator, and show that the exact results can be well reproduced. In addition to the reduced density matrix, our approach also provides a link to the total wave function by introducing new boson operators.
Comments:
45 pages, 8 figures, 2 tables
Subjects:
Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th)
arXiv:
1909.10418 [pdf]
Annals Phys.(2020)·10 citations
14
[Submitted on 23 Sept 2019] (cross-list from hep-ph)
Global fluid fits to identified particle transverse momentum spectra from heavy-ion collisions at the Large Hadron Collider
D. Devetak🇩🇪 · A. Dubla🇩🇪 · S. Floerchinger🇩🇪 · E. Grossi🇩🇪 · S. Masciocchi🇩🇪 · A. Mazeliauskas🇨🇭 · I. Selyuzhenkov🇩🇪
Transverse momentum spectra of identified particles produced in heavy-ion collisions at the Large Hadron Collider are described with relativistic fluid dynamics. We perform a systematic comparison of experimental data for pions, kaons and protons up to a transverse momentum of 3 GeV $/ c$ with calculations using the FluiduM code package to solve the evolution equations of fluid dynamics, the TrENTo model to describe the initial state and the FastReso code to take resonance decays into account. Using data in five centrality classes at the center-of-mass collision energy per nucleon pair $s_{NN} = 2.76 TeV$ , we determine systematically the most likely parameters of our theoretical model including the shear and bulk viscosity to entropy ratios, the initialization time, initial density and freeze-out temperature through a global search and quantify their posterior probability. This is facilitated by the very efficient numerical implementation of FluiduM and FastReso. Based on the most likely model parameters we present predictions for the transverse momentum spectra of multi-strange hadrons as well as identified particle spectra from Pb-Pb collisions at $s_{NN} = 5.02 TeV$ .
Comments:
13 pages, 7 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1909.10485 [pdf]
JHEP(2020)·50 citations

Affiliations

first authorsco-authorsvia INSPIRE

Analytic solutions of the Schrödinger equation with non-central generalized inverse quadratic Yukawa potential

Temperature Dependence of the Axion Mass in a Scenario Where the Restoration of Chiral Symmetry Drives the Restoration of the UA​(1) Symmetry

Towards a combined analysis of inclusive/exclusive electroproduction

The Hellmann-Feynman theorem at finite temperature

Consistency checks for two-body finite-volume matrix elements: I. Conserved currents and bound states

A new approach for open quantum systems based on a phonon number representation of a harmonic oscillator bath

Global fluid fits to identified particle transverse momentum spectra from heavy-ion collisions at the Large Hadron Collider

Affiliations

Temperature Dependence of the Axion Mass in a Scenario Where the Restoration of Chiral Symmetry Drives the Restoration of the $U_{A} (1)$ Symmetry