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Nuclear Theory·nucl-th

Tuesday·February 20, 2024

15 papers—6 primary·9 cross-listed

All15Primary6Cross-lists9
  1. 01

    [Submitted on 17 Feb 2024]

    An Efficient Quantum Circuit for Block Encoding a Pairing Hamiltonian

    Diyi Liu🇺🇸 · Weijie Du🇺🇸 · Lin Lin🇺🇸 · James P.Vary🇺🇸 · Chao Yang🇺🇸

    We present an efficient quantum circuit for block encoding pairing Hamiltonian often studied in nuclear physics. Our block encoding scheme does not require mapping the creation and annihilation operators to the Pauli operators and representing the Hamiltonian as a linear combination of unitaries. Instead, we show how to encode the Hamiltonian directly using controlled swap operations. We analyze the gate complexity of the block encoding circuit and show that it scales polynomially with respect to the number of qubits required to represent a quantum state associated with the pairing Hamiltonian. We also show how the block encoding circuit can be combined with the quantum singular value transformation to construct an efficient quantum circuit for approximating the density of states of a pairing Hamiltonian. The techniques presented can be extended to encode more general second-quantized Hamiltonians.

    Comments:
    27 pages, 18 figures
    Subjects:
    Nuclear Theory (nucl-th); cs.NA (cs.NA); math.NA (math.NA); Quantum Physics (quant-ph)
    arXiv:
    2402.11205 [pdf]
    Journal of Computational Science(2025)·17 citations
  2. 02

    [Submitted on 17 Feb 2024]

    The pervasiveness of shape coexistence in nuclear pair condensates

    Y. Lei · J. Qi · Y. Lu · H. Jiang · Z. Z. Qin · D. Liu · Calvin W. Johnson

    We investigate nuclear shape coexistence for a wide range of even-even nuclides. By varying general pair condensates, which include Slater determinants as a limit but also allow for arbitrary pairing channels, we frequently find multiple coexisting mimina, and often more than two. This is consistent with recent experimental results. In order to measure general pairwise correlations beyond a simple Slater determinant, we introduce a novel entropy-like measure, which is smallest mid-shell and largest near shell closures; this is consistent with a picture of pairing-like behavior dominating near closed shells and deformation mid-shell. After surveying nuclides spanning from the shell to nuclides between magic numbers 50 and 82, we focus on the six lightest nuclei with shape coexistence. Angular-momentum projected variational pair condensate (PVPC) calculations identify band structures, including two newly proposed coexisting bands in Si/Mg and Si/Ne. The PVPC results agree well with data, providing robust experimental support for the pervasiveness of coexistence in these light nuclei.

    Comments:
    13 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2402.11276 [pdf]
    PRC(2024)·4 citations
  3. 03

    [Submitted on 17 Feb 2024]

    Neural network study on nuclear ground-state spin distribution within random interaction ensemble

    Deng Liu · Alam Noor A · Zhenzhen Qin · Yang Lei

    The distribution of nuclear ground-state spin in the two-body random ensemble (TBRE) is studied by using a general classification neural network (NN) model with the two-body interaction matrix elements as input features and corresponding ground-state spins as labels or output predictions. It seems that quantum many-body system problem exceeds the capability of our optimized neural networks when it comes to accurately predicting the ground-state spin of each sample within the TBRE. However, our neural network model effectively captures the statistical properties of the ground-state spin. This may be attributed to the fact that the neural network (NN) model has learned the empirical regularity of the ground-state spin distribution in TBRE, as discovered by human physicists.

    Comments:
    10 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2402.11278 [pdf]
    Nucl.Sci.Tech.(2024)·3 citations
  4. 04

    [Submitted on 17 Feb 2024]

    Bottomonium evolution with in-medium heavy quark potential from lattice QCD

    Ge Chen🇬🇧 · Baoyi Chen🇨🇳 · Jiaxing Zhao🇫🇷

    The static properties and dynamic evolution of bottomonium states in a hot QCD medium are investigated through the Schrödinger equation with complex heavy quark potentials, which are presented recently in lattice QCD study and with three different extractions. This approach builds a direct connection between the in-medium heavy quark potentials from the lattice QCD to the experimental observables. The yields and nuclear modification factors of bottomonium in Pb-Pb collisions at are calculated in this work. Our results show a large suppression of the bottomonium yield in heavy ion collisions due to the large imaginary potential. To understand bottomonium based on lattice QCD potentials, we propose a fomration time for bottomonium states and find that experimental data can be well explained with the heavy quark potential extracted by the Padé fit, which shows no color screening in the real part potential.

    Comments:
    7 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2402.11316 [pdf]
    EPJC(2024)·9 citations
  5. 05

    [Submitted on 18 Feb 2024]

    High Quality Microscopic Nuclear Masses of Superheavy Nuclei

    Dawei Guan · Junchen Pei

    To synthesize new superheavy elements, the accurate prediction of nuclear masses of superheavy nuclei is essential for calculations of reaction values, neutron separation energies and -decay energies, which are important for estimating beam energies, survival probabilities and also for identifications. In this work, we include existing -decay energies of superheavy nuclei in the fitting procedure of extended Skyrme density functionals as corresponding nuclear masses are not available. Systematic -decay energies are well reproduced with deviations smaller than 0.2 MeV. The high quality -decay energies make it feasible for direct identification of new elements and new isotopes. The resulting binding energies in the heaviest region are surprisingly close to the inferences by AME2020. Our work should be useful for guiding experimental synthesis of new elements 119 and 120.

    Comments:
    5 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2402.11514 [pdf]
    PLB(2024)·17 citations
  6. 06

    [Submitted on 18 Feb 2024]

    Bayesian uncertainty quantification on nuclear level density data and their impact on reactions of astrophysical interest

    A. Chalil (1) · C. Ducoin (1) · O. Stézowski (1) · N. Millard-Pinard (1) · J. Dudouet (1) · Y. Demane (1) · M. Chamseddine (1) ((1) Univ. Lyon, Univ. Claude Bernard Lyon (1), (CNRS/IN2P3), (IP2I) Lyon, Villeurbanne, France)

    The process nucleosynthesis is responsible for the synthesis of 35 neutron-deficient nuclei from Se to Hg. An important input that can affect the modeling of this process is the nuclear level density at the relevant excitation energies of the nuclei involved in the reaction network. The OSLO method has been extensively used for the measurement of level densities in excitation energies of several MeV. In this work, Bayesian optimization has been used in order to estimate the 95% high density intervals for the parameters of two level density models optimized on the OSLO data. These uncertainties are then propagated on the cross sections of reactions leading to the compound nuclei Pd and Cd inside the astrophysically relevant energy range. Imposing constraints in this region of the isotopic chart is important for network calculations involving the nearby nuclei Pd and Cd. We discuss the reduction of the range of cross sections due to the uncertainties arising from the level density data compared to the range of the six default level density models available in TALYS and we highlight the need for level density data inside the astrophysically relevant energy ranges.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2402.11535 [pdf]
    PRC(2024)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE