Nuclear Theory·nucl-th

Tuesday·May 28, 2019

17 papers—8 primary·9 cross-listed

09
Digitization of Scalar Fields for Quantum Computing
Natalie Klco🇺🇸 · Martin J. Savage🇺🇸
Qubit, operator and gate resources required for the digitization of lattice $λ ϕ^{4}$ scalar field theories onto quantum computers are considered, building upon the foundational work by Jordan, Lee and Preskill, with a focus towards noisy intermediate-scale quantum (NISQ) devices. The Nyquist-Shannon sampling theorem, introduced in this context by Macridin, Spentzouris, Amundson and Harnik building on the work of Somma, provides a guide with which to evaluate the efficacy of two field-space bases, the eigenstates of the field operator, as used by Jordan, Lee and Preskill, and eigenstates of a harmonic oscillator, to describe $0 + 1$ - and $d + 1$ -dimensional scalar field theory. We show how techniques associated with improved actions, which are heavily utilized in Lattice QCD calculations to systematically reduce lattice-spacing artifacts, can be used to reduce the impact of the field digitization in $λ ϕ^{4}$ , but are found to be inferior to a complete digitization-improvement of the Hamiltonian using a Quantum Fourier Transform. When the Nyquist-Shannon sampling theorem is satisfied, digitization errors scale as $∣ lo g ∣ lo g ∣ ϵ_{dig} ∣∣∣ \sim n_{Q}$ (number of qubits describing the field at a given spatial site) for the low-lying states, leaving the familiar power-law lattice-spacing and finite-volume effects that scale as $∣ lo g ∣ ϵ_{latt} ∣∣ \sim N_{Q}$ (total number of qubits in the simulation). For localized(delocalized) field-space wavefunctions, it is found that $n_{Q} \sim 4 (7)$ qubits per spatial lattice site are sufficient to reduce theoretical digitization errors below error contributions associated with approximation of the time-evolution operator and noisy implementation on near-term quantum devices.
↳ quant-phhep-lathep-phnucl-thPRA(2019)·215 citations
10
Close Binary Galaxies: Application to Source of Energy and Expansion in Universe
V. V. Sargsyan · H. Lenske · G. G. Adamian · N. V. Antonenko
Applying the microscopic nuclear physics ideas for fusion reactions to macroscopic galactic systems, we study the evolution of the compact binary galaxy in mass asymmetry (transfer) coordinate. The conditions for the formation of stable symmetric binary galaxy are analyzed. The role of symmetrization of asymmetric binary galaxy in the transformation of gravitational energy into internal energy of galaxies accompanied by the release of a large amount of energy during the symmetrization process is revealed.
↳ astro-ph.GAnucl-thIJMPE(2019)·3 citations
11
A Study of Stress-Tensor Distribution around Flux Tube in Abelian-Higgs Model
Ryosuke Yanagihara🇯🇵 · Masakiyo Kitazawa🇯🇵
We study the stress-tensor distribution around the flux tube in static quark and anti-quark systems based on the momentum conservation and the Abelian-Higgs (AH) model. We first investigate constraints on the stress-tensor distribution from the momentum conservation and show that the effect of boundaries plays a crucial role to describe the structure of the flux tube in SU(3) Yang-Mills theory which has measured recently on the lattice. We then study the distributions of the stress tensor and energy density around the magnetic vortex with and without boundaries in the AH model, and compare them with the distributions in SU(3) Yang-Mills theory based on the dual superconductor picture. It is shown that a wide parameter range of the AH model is excluded by a comparison with the lattice results in terms of the stress tensor.
↳ hep-phhep-latnucl-thPTEP(2019)·22 citations
12
Pion scattering in the isospin I=2 channel from elongated lattices
C. Culver🇺🇸 · M. Mai🇺🇸 · A. Alexandru🇺🇸 · M. Doring🇺🇸 · F. X. Lee🇺🇸
Pion-pion elastic scattering in the isospin I=2 channel is investigated in two-flavor dynamical lattice QCD. Six ensembles are used with lattices elongated in one of the spatial dimensions at two quark masses corresponding to a pion mass of 315 MeV and 226 MeV. The energy of the low-lying states below the inelastic threshold are extracted in each case using the standard variational method.The extracted finite-volume spectrum is fitted by the inverse amplitude method simultaneously for both quark masses and extrapolated thereafter to the physical point. The resulting phase-shifts and scattering length are compared with those from experiment, leading-order chiral perturbation theory and other lattice studies. Our calculations match the experimental results.
↳ hep-lathep-phnucl-thPRD(2019)·47 citations
13
Canonical interpretation of $Y (10750)$ and $Υ (10860)$ in the $Υ$ family
Qi Li🇨🇳 · Ming-Sheng Liu🇨🇳 · Qi-Fang Lü🇨🇳 · Long-Cheng Gui🇨🇳 · Xian-Hui Zhong🇨🇳
Inspired by the new resonance $Y (10750)$ , we calculate the masses and two-body OZI-allowed strong decays of the higher vector bottomonium sates within both screened and linear potential models. We discuss the possibilities of $Υ (10860)$ and $Y (10750)$ as mixed states via the $S - D$ mixing. Our results suggest that $Y (10750)$ and $Υ (10860)$ might be explained as mixed states between $5 S$ - and $4 D$ -wave vector $b b ˉ$ states. The $Y (10750)$ and $Υ (10860)$ resonances may correspond to the mixed states dominated by the $4 D$ - and $5 S$ -wave components, respectively. The mass and the strong decay behaviors of the $Υ (11020)$ resonance are consistent with the assignment of the $Υ (6 S)$ state in the potential models.
↳ hep-phhep-exnucl-thEPJC(2020)·36 citations
14
Electron-capture Rates in $^{20}$ Ne for a Forbidden Transition to the Ground State of $^{20}$ F Relevant to Final Evolution of High-density O-Ne-Mg Cores
Toshio Suzuki · Shuai Zha · Shing-Chi Leung · Ken'ichi Nomoto
Electron capture on $^{20}$ Ne is critically important for the final stage of evolution of stars with the initial masses of 8 - 10 $M_{⊙}$ . In the present paper, we evaluate electron capture rates for a forbidden transition $^{20}$ Ne (0 $_{g . s .}^{+}$ ) $\to$ $^{20}$ F (2 $_{g . s .}^{+}$ ) in stellar environments by the multipole expansion method with the use of shell-model Hamiltonians. These rates have not been accurately determined in theory as well as in experiments. Our newly evaluated rates are compared with those obtained by a prescription that treats the transition as an allowed Gamow-Teller (GT) transition with the strength determined from a recent $β$ -decay experiment for $^{20}$ F (2 $_{g . s .}^{+}$ ) $\to$ $^{20}$ Ne (0 $_{g . s .}^{+}$ ) \citep{Kirsebom}. We find that different electron energy dependence of the transition strengths between the two methods leads to sizable differences in the weak rates of the two methods. We also find that the Coulomb effects, that is, the effects of screening on ions and electrons are non-negligible. We apply our e-capture rates on $^{20}$ Ne to the calculation of the evolution of high-density O-Ne-Mg cores of 8 - 10 $M_{⊙}$ stars. We find that our new rates affect the abundance distribution and the central density at the final stage of evolution.
↳ astro-ph.SRnucl-thApJ(2019)·19 citations
15
Quantum Kinetic Theory of Spin Polarization of Massive Quarks in Perturbative QCD: Leading Log
Shiyong Li🇺🇸 · Ho-Ung Yee🇺🇸
We present the quantum kinetic equation for spin polarization of massive quarks in leading log order of perturbative QCD, which describes time evolution of the spin density matrix in momentum space of a massive quark interacting with a background QCD plasma. We find that the time evolution operator of the spin density matrix, or the quantum kinetic collision terms, are universally of order $α_{s}^{2} lo g (1/ α_{s})$ in terms of the QCD coupling constant $α_{s} = g^{2} / (4 π)$ . Our quantum kinetic equation is valid for an arbitrary quark mass $m ≫ m_{D} \sim g T$ , where $m_{D}$ is the Debye mass, and can be used to study relaxation dynamics of spin polarization of massive quarks in perturbative QCD regime.
↳ hep-phhep-thnucl-thPRD(2019)·88 citations
16
Structure of $^{38}$ Cl and the quest for a comprehensive shell model interaction
R. S. Lubna (1) · K. Kravvaris (1 and 2) · S. L. Tabor (1) · Vandana Tripathi (1) · A. Volya (1) · E. Rubino (1) · J. M. Allmond (3) · B. Abromeit (1) · L. T. Baby (1) · T. C. Hensley (1) ((1) Florida State University, Tallahassee, (2) Lawrence Livermore National Laboratory, Livermore, (3) Physics Division, Oak Ridge National Laboratory)
The higher-spin structure of $^{38}$ Cl ( $N = 21$ ) was investigated following the $^{26}$ Mg( $^{14}$ C, $p n$ ) reaction at 30 and 37 MeV beam energies. The outgoing protons were detected in an $E - Δ E$ Si telescope placed at 0 $^{\circ}$ close to the target with a Ta beam stopper between the target and telescope. Multiple $γ$ rays were detected in time coincidence with the protons using an enhanced version of the FSU $γ$ detection array. The level scheme was extended up to 8420 keV with a likely spin of 10 $ℏ$ . A new multishell interaction was developed guided by the experimental information. This FSU interaction was built by fitting to the energies of 270 experimental states from $^{13}$ C to $^{51}$ Ti. Calculations using the FSU interaction reproduce observed properties of $^{38}$ Cl rather well, including the spectroscopic factors. The interaction has been successfully used to interpret the $1 p 1 h$ and $2 p 2 h$ configurations in some nearby nuclei as well.
↳ nucl-exnucl-thPRC(2019)·35 citations
17
Neutron stars in general relativity and scalar-tensor theory of gravity
F. J. Fattoyev🇺🇸
The masses and radii of neutron stars are discussed in general relativity and scalar-tensor theory of gravity and the differences are compared with the current uncertainties stemming from the nuclear equation of state in the relativistic mean-field framework. It is shown that astrophysical and gravitational waves observations of radii of neutron stars with masses $M ≲ 1.4 M_{⊙}$ constrain only the nuclear equation of state, and in particular the density dependence of the nuclear symmetry energy. Future observations of massive neutron stars may constrain the coupling parameters of the scalar-tensor theory provided that a general consensus on the dense nuclear matter equation of state is reached.
↳ gr-qcastro-ph.HEnucl-thArab.J.Math.(2019)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE