Nuclear Theory·nucl-th

Tuesday·December 20, 2022

16 papers—6 primary·10 cross-listed

01
[Submitted on 17 Dec 2022]
Quantum computing of the pairing Hamiltonian at finite temperatures
Chongji Jiang🇨🇳 · Junchen Pei🇨🇳
In this work, we study the pairing Hamiltonian with four particles at finite temperatures on a quantum simulator and a superconducting quantum computer. The excited states are obtained by the variational quantum deflation (VQD). The error-mitigation methods are applied to improve the noisy results. The simulation of thermal excitation states is performed using the same variational circuit as at zero temperature. The results from quantum computing become close to exact solutions at high temperatures, and demonstrate a smooth superfluid-normal phase transition as a function of temperatures as expected in finite systems.
Comments:
10 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2212.08862 [pdf]
PRC(2023)·5 citations
02
[Submitted on 17 Dec 2022]
Excited states of zero seniority based on a pair condensate
Th. Popa · N. Sandulescu · M. Sambataro
We study the excited states of zero seniority for various like-particle systems interacting by pairing forces and by general two-body interactions. We consider two types of excitations, generated from a ground state described by a pair condensate. One type is obtained by breaking a pair from the ground state condensate and replacing it by "excited" collective pairs built on time-reversed single-particle orbits. The second type of zero seniority excited states is described by a condensate of identical excited pairs. The structure of these excited states is analysed for the picked fence model and for the valence neutrons of $^{108}$ Sn. For a state-depending pairing interaction, the first type of excited states agree well with the J=0 states which are known in $^{108}$ Sn. At the same time, these states can be also associated unambiguously with those exact states which are the closest in energy to the experimental levels. The states corresponding to the excited pair condensate appear at low energies, around the energy of the second excited state of the first type, and they do not have a simple correspondence with exact eigenstates. However, at a much higher excitation energy there is an exact state which is similar in structure to an EPC state. It is shown that this EPC state has the features of a giant pairing vibration.
Comments:
22 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2212.08919 [pdf]
PRC(2023)·2 citations
03
[Submitted on 17 Dec 2022]
Consideration of memory of spin and parity in the fissioning compound nucleus by applying the Hauser-Feshbach fission fragment decay model to photonuclear reactions
Toshihiko Kawano · Amy E. Lovell · Shin Okumura · Hirokazu Sasaki · Ionel Stetcu · Patrick Talou
Prompt and $β$ -delayed fission observables, such as the average number of prompt and delayed neutrons, the independent and cumulative fission product yields, and the prompt $γ$ -ray energy spectra for the photonuclear reactions on $^{235, 238}$ U and $^{239}$ Pu are calculated with the Hauser-Feshbach Fission Fragment Decay (HF $^{3}$ D) model and compared with available experimental data. In the analysis of neutron-induced fission reactions to the case of photo-induced fission, an excellent reproduction of the delayed neutron yields supports a traditional assumption that the photo-fission might be similar to the neutron-induced fission at the same excitation energies regardless of the spin and parity of the fissioning systems.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2212.08943 [pdf]
PRC(2023)·4 citations
04
[Submitted on 19 Dec 2022]
Temperature dependence of cluster decay
D. F. Rojas-Gamboa · N. G. Kelkar · O. L. Caballero
A universal decay law (UDL) for light cluster decay of excited nuclei is formulated by fitting the UDL half-lives to those evaluated within an excitation energy-dependent double folding model (DFM). The half-lives are evaluated within a preformed cluster model. The excitation energy dependence is introduced both in the energy of the emitted cluster and in the interaction potential through the density distributions of the interacting nuclei. The half-lives are found to decrease when the difference between the excitation energies of the parent and daughter nuclei, $Δ E^{*} >$ 0, increases, with the reduction being a few orders of magnitude for higher values of $Δ E^{*}$ . This can be of importance for nucleosynthesis calculations of heavy elements formed in extremely hot environments, as well as in highly energetic heavy-ion collisions. The UDL for excited nuclei is used to provide an estimate of the enhancement in the cluster decay rates of thermally excited nuclei such as those produced in r-process nucleosynthesis.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2212.09221 [pdf]
NPA(2022)·2 citations
05
[Submitted on 19 Dec 2022]
A Powerful New Energy Density Functional
Anthony W Thomas🇦🇺 · Pierre A M Guichon🇫🇷 · Jesper Leong🇦🇺 · K L Martinez-Paglinawan · J R Stone🇬🇧
We describe the most recent energy density functional derived within the quark meson coupling model. Although fit to the binding energies and charge radii of just seventy magic nuclei, the accuracy with which it reproduces nuclear properties across the entire periodic table is outstanding. As well as outlining a number of those results, we present an argument explaining why having a physically motivated model with a small number of parameters is especially desirable as one seeks to make predictions in new regions of N and Z. As an example we show the predictions for known super-heavy nuclei that were not included in the fit.
Comments:
Contribution to INPC2022
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2212.09228 [pdf]
J.Phys.Conf.Ser.(2023)·2 citations
06
[Submitted on 19 Dec 2022]
Strong magnetic fields and pasta phases revisited
Luigi Scurto🇵🇹 · Helena Pais🇪🇸 · Francesca Gulminelli🇫🇷
In this work, we compute the structure and composition of the inner crust of a neutron star in the presence of a strong magnetic field, such as it can be found in magnetars. To determine the geometry and characteristics of the crust inhomogeneities, we consider the compressible liquid drop model, where surface and Coulomb terms are included in the variational equations, and we compare our results with previous calculations based on more approximate treatments. For the equation of state (EoS), we consider two non-linear relativistic mean-field models with different slopes of the symmetry energy, and we show that the extension of the inhomogeneous region inside the star core due to the magnetic field strongly depends on the behavior of the symmetry energy in the crustal EoS. Finally, we argue that the extended spinodal instability observed in previous calculations can be related to the presence of small amplitude density fluctuations in the magnetar outer core, rather than to a thicker solid crust. The compressible liquid drop model formalism, while in overall agreement with the previous calculations, leads to a systematic suppression of the metastable solutions, thus allowing a more precise estimation of the crust-core transition density and pressure, and therefore a better estimation of the crustal radius.
Comments:
11 pages, 5 figures, 3 tables. Version published on Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2212.09355 [pdf]
PRC(2023)·13 citations
07
[Submitted on 17 Dec 2022] (cross-list from hep-ph)
Hot Spot model of Nucleon and Double Parton Scattering
B. Blok (Technion)🇮🇱 · R. Segev (Technion)🇮🇱 · M. Strikman (Penn State University)🇺🇸
We calculate the rate of double parton scattering (DPS) in proton - proton collisions in the framework of the recently proposed hot spot model of the nucleon structure. The resulting rate, especially for the case of three hot spots, appears to be in tension with the current experimental data on DPS at the LHC.
Comments:
12 pages 2 figures 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2212.08848 [pdf]
EPJC(2023)·4 citations
08
[Submitted on 17 Dec 2022] (cross-list from hep-ph)
Spatial diffusion of heavy quarks in background magnetic field
Sarthak Satapathy🇮🇳 · Sudipan De🇮🇳 · Jayanta Dey🇮🇳 · Sabyasachi Ghosh🇮🇳
The ratio of shear viscosity to entropy density shows a valley-shaped pattern well-known in the community of heavy-ion physics. Diffusion coefficients of heavy quark and meson shows the similar structure, and both sketches have become quite popular in the community. Present work has attempted a finite magnetic field extension of the diffusion coefficients of heavy quark and meson. Using Einstein's diffusion relation, we calculated heavy quark and heavy meson diffusion by the ratio of conductivity to susceptibility in the kinetic theory framework of relaxation time approximation. The relaxation time of heavy quark and meson are tuned from the knowledge of earlier works on spatial diffusion estimations, and then we have extended the framework for a finite magnetic field, where our outcomes have revealed two aspects - anisotropic and quantum aspects of diffusion with future possibilities of phenomenological signature.
Comments:
17 pages, 11 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2212.08933 [pdf]
PRC(2024)·13 citations
09
[Submitted on 18 Dec 2022] (cross-list from hep-lat)
Equation of state and speed of sound of (2+1)-flavor QCD in strangeness-neutral matter at non-vanishing net baryon-number density
D. Bollweg🇺🇸 · D. A. Clarke🇩🇪 · J. Goswami🇯🇵 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · Swagato Mukherjee🇺🇸 · P. Petreczky🇺🇸 · C. Schmidt🇩🇪 · Sipaz Sharma🇩🇪
We update results on the QCD equation of state in (2+1)-flavor QCD with non-zero conserved charge chemical potentials obtained from an eighth-order Taylor series. We present results for basic bulk thermodynamic observables of strangeness-neutral strong-interaction matter, i.e. pressure, number densities, energy and entropy density, and resum Taylor series results using Padé approximants. Furthermore, we calculate the speed of sound as well as the adiabatic compression factor of strangeness-neutral matter on lines of constant entropy per net baryon number. We show that the equation of state ( $P (n_{B}), ϵ (n_{B})$ ) is already well described by the $4^{th}$ -order Taylor series in almost the entire range of temperatures accessible with the beam energy scan in collider mode at the Relativistic Heavy Ion Collider.
Comments:
22 pages, 17 figures, minor revision and journal reference added
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2212.09043 [pdf]
PRD(2023)·75 citations
10
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Bose-Einstein Condensation and Dissipative Dynamics in a Relativistic Pion Gas
Kshitish Kumar Pradhan🇮🇳 · Dushmanta Sahu🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳
Pion condensation in ultra-relativistic collisions presents a compelling theoretical phenomenon with significant implications for the dynamics of hadronic matter. Various theoretical frameworks offer insight into the nature of high-temperature Bose-Einstein condensation (BEC). The present study investigates the dissipative behavior of a relativistic pion gas undergoing Bose-Einstein condensation (BEC) in ultra-relativistic heavy-ion collisions. Further, we obtain viscosity ( $η$ ), bulk viscosity ( $ζ$ ), and speed of sound ( $c_{s}$ ) by employing the Boltzmann transport equation with the relaxation time approximation. Findings show a substantial drop in $η / s$ and $ζ / s$ with the fractional increase in condensation. This effect is becoming more evident in larger systems approaching the thermodynamic limit. Alongside the reduction in viscosities, the speed of sound also decreases with increasing condensation, indicating a softening of the equation of state. The analysis of finite-size effects reveals that larger systems exhibit more pronounced signatures of BEC. These results suggest that pion condensation can influence the hydrodynamic evolution of the hadronic phase in heavy-ion collisions, with consequential implications for interpreting collective flow observables and the underlying equation of state.
Comments:
Same as the published version in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2212.09288 [pdf]
PRD(2025)·4 citations
11
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Studying the 3+1D structure of the Glasma using the weak field approximation
Andreas Ipp🇦🇹 · Markus Leuthner🇦🇹 · David I. Müller🇦🇹 · Soeren Schlichting🇩🇪 · Pragya Singh🇫🇮
We extend the weak field approximation for the Glasma beyond the boost-invariant approximation, which allows us to compute rapidity-dependent observables in the early stages of heavy-ion collisions. We show that in the limit of small fields, the weak field approximation agrees quantitatively with non-perturbative lattice simulations. Furthermore, we demonstrate that the rapidity profile of the transverse pressure is determined by longitudinal color correlations within the colliding nuclei.
Comments:
8 pages, 4 figures, parallel talk given at the XVth Quark Confinement and the Hadron Spectrum conference
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2212.09363 [pdf]
EPJ Web Conf.(2022)·6 citations
12
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Twist-four gravitational form factor at NNLO QCD from trace anomaly constraints
Kazuhiro Tanaka (Juntendo Univ.)🇯🇵
It is known that the trace anomaly in the QCD energy-momentum tensor $T^{μν}$ can be attributed to the anomalies for each of the gauge-invariant quark part and gluon part of $T^{μν}$ , and their explicit three-loop formulas have been derived in the $MS$ scheme in the dimensional regularization. The matrix elements of this quark/gluon decomposition of the QCD trace anomaly allow us to derive the QCD constraints on the hadron's gravitational form factors, in particular, on the twist-four gravitational form factor, $C ˉ_{q, g}$ . Using the three-loop quark/gluon trace anomaly formulas, we calculate the forward (zero momentum transfer) value of the twist-four gravitational form factor $C ˉ_{q, g}$ at the next-to-next-to-leading-order (NNLO) accuracy. We present quantitative results for nucleon as well as for pion, leading to a model-independent determination of the forward value of $C ˉ_{q, g}$ . We find quite different pattern in the obtained results between the nucleon and the pion. In particular, for the nucleon, the present information from experiment and lattice QCD on the nonperturbative matrix elements arising in our NNLO formula allows us to obtain a prediction of the forward value of $C ˉ_{q, g}$ at the accuracy of a few percent level.
Comments:
40 pages, 5 figures; v3: typos corrected, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2212.09417 [pdf]
JHEP(2023)·20 citations
13
[Submitted on 19 Dec 2022] (cross-list from hep-lat)
Monopole and instanton effects on connected and disconnected correlations for scalar density
Masayasu Hasegawa🇷🇺
This study investigates the effects on the connected and disconnected correlations for the scalar density that are induced by created monopoles and instantons in the QCD vacuum. To reveal the effects, we add a monopole and anti-monopole pair in the gauge field configurations in \textit{SU}(3) by applying the monopole creation operator to the vacuum. We vary the magnetic charges of the monopole and anti-monopole and increase the number of monopoles and anti-monopoles in the configurations. The Dirac operator of overlap fermions preserves the exact chiral symmetry in lattice gauge theory and exact zero-modes exist in its spectrum. The eigenvalues and eigenvectors of the overlap Dirac operator have been calculated using these configurations, and the numbers of instantons and anti-instantons which are created by these additional monopoles and anti-monopoles have been estimated from the numbers of topological charges in our previous studies. In this study, we demonstrate the preliminary results that instantons and monopoles influence the masses that are evaluated from the connected and disconnected correlation functions for the scalar density using low-lying eigenvalues and eigenvectors of the overlap Dirac operator.
Comments:
This report is a contribution to the proceedings of "the 6th International Conference on Particle Physics and Astrophysics'' and accepted for publication in Physics of Atomic Nuclei. This report contains 5 figures and 5 tables on 12 pages
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2212.09691 [pdf]
Phys.Atom.Nucl.(2023)·0 citations
14
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Inspection of the detection cross section dependence of the Gallium Anomaly
C. Giunti🇮🇹 · Y.F. Li🇨🇳 · C.A. Ternes🇮🇹 · Z. Xin🇨🇳
We discuss in detail the dependence of the Gallium Anomaly on the detection cross section. We provide updated values of the size of the Gallium Anomaly and find that its significance is larger than about $5 σ$ for all the detection cross section models. We discuss the dependence of the Gallium Anomaly on the assumed value of the half life of $^{71} Ge$ , which determines the cross sections of the transitions from the ground state of $^{71} Ga$ to the ground state of $^{71} Ge$ . We show that a value of the $^{71} Ge$ half life which is larger than the standard one can reduce or even solve the Gallium Anomaly. Considering the short-baseline neutrino oscillation interpretation of the Gallium Anomaly, we show that a value of the $^{71} Ge$ half life which is larger than the standard one can reduce the tension with the results of other experiments. Since the standard value of the $^{71} Ge$ half life was measured in 1985, we advocate the importance of new measurements with modern technique and apparatus for a better assessment of the Gallium Anomaly.
Comments:
v3: 11 pages, 4 figures, 3 tables, references added, typo corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2212.09722 [pdf]
PLB(2023)·27 citations
15
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Anisotropic fluctuations of angular momentum of heavy quarks in the Glasma
Pooja🇮🇳 · Santosh K. Das🇮🇳 · Vincenzo Greco🇮🇹 · Marco Ruggieri🇮🇹
We study the evolution of the angular momentum of the heavy quarks in the very early stage of high energy nuclear collisions, in which the background is made of evolving Glasma fields. Given the novelty of the problem, we limit ourselves to the use of toy heavy quarks with a large, unphysical mass, in order to implement the kinetic equations for the angular momentum in the non-relativistic limit. We find that as a consequence of the anisotropy of the background fields, angular momentum fluctuations are also anisotropic: we understand this in simple terms relating the fluctuations of the angular momentum, $L$ , to those of linear momentum. While orbital angular momentum diffuses and develops substantial fluctuations and anisotropies, the spin does not. Hence, we can identify the fluctuations of $L$ with those of the total angular momentum $J = L + S$ . Therefore, our study suggests that the total angular momentum of the heavy quarks in the early stage of high energy nuclear collisions will present anisotropic fluctuations.
Comments:
10 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2212.09725 [pdf]
Eur.Phys.J.Plus(2023)·18 citations
16
[Submitted on 19 Dec 2022] (cross-list from astro-ph.HE)
Prospects for constraining twin stars with next-generation gravitational-wave detectors
Philippe Landry🇨🇦 · Kabir Chakravarti🇨🇿
Neutron star equations of state with strong phase transitions may support twin stars, hybrid and hadronic stars with the same mass but different tidal deformabilities. The presence of twin stars in the population of merging neutron stars produces distinctive gaps in the joint distribution of binary tidal deformabilities and chirp masses. We analyze a simulated population of binary neutron star mergers recovered with a network of next-generation (XG) ground-based gravitational-wave detectors to determine how many observations are needed to infer, or rule out, the existence of twin stars. Using a hierarchical inference framework based on a simple parametric twin-star model, we find that a single week of XG observations may suffice to detect a tidal deformability difference of several hundred between twins and measure the mass scale at which twins occur to within a few percent. For less pronounced twins, XG observations will place a stringent upper bound on the tidal deformability difference.
Comments:
13 pages, 12 figures, 1 table
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2212.09733 [pdf]
13 citations

Affiliations

first authorsco-authorsvia INSPIRE