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Nuclear Theory·nucl-th

Friday·March 4, 2022

4 papers—3 primary·1 cross-listed

All4Primary3Cross-lists1
  1. 01

    [Submitted on 3 Mar 2022]

    Simulating excited states of the Lipkin model on a quantum computer

    Manqoba Q. Hlatshwayo🇺🇸 · Yinu Zhang🇺🇸 · Herlik Wibowo🇹🇼 · Ryan LaRose🇺🇸 · Denis Lacroix🇫🇷 · Elena Litvinova🇺🇸

    We simulate the excited states of the Lipkin model using the recently proposed Quantum Equation of Motion (qEOM) method. The qEOM generalizes the EOM on classical computers and gives access to collective excitations based on quasi-boson operators of increasing configuration complexity . We show, in particular, that the accuracy strongly depends on the fermion to qubit encoding. Standard encoding leads to large errors, but the use of symmetries and the Gray code reduces the quantum resources and improves significantly the results on current noisy quantum devices. With this encoding scheme, we use IBM quantum machines to compute the energy spectrum for a system of and particles and compare the accuracy against the exact solution. We found that the results of the approach with , an analog of the second random phase approximation (SRPA), are, in principle, more accurate than with , which corresponds to the random phase approximation (RPA), but the SRPA is more amenable to noise for large coupling strengths. Thus, the proposed scheme shows potential for achieving higher spectroscopic accuracy by implementations with higher configuration complexity, if a proper error mitigation method is applied.

    Comments:
    Article: 20 pages, 10 figures
    Subjects:
    Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2203.01478 [pdf]
    PRC(2022)·36 citations
  2. 02

    [Submitted on 3 Mar 2022]

    Overview of intermittency analysis in heavy-ion collisions

    Zhiming Li🇨🇳

    In this paper, a search for power-law fluctuations with fractality and intermittency analysis to explore the QCD phase diagram and the critical point is summarized. Experimental data on self-similar correlations and fluctuations with respect to the size of phase space volume in various high energy heavy-ion collisions are presented, with special emphasis on background subtraction and efficiency correction of the measurement. Phenomenological modelling and theoretical work on the subject are discussed. Finally, we highlight possible directions for future research.

    Comments:
    Invited brief review from MPLA, modified according to the journal requirement and a few typos corrected
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2203.01490 [pdf]
    Mod.Phys.Lett.A(2022)·13 citations
  3. 03

    [Submitted on 3 Mar 2022]

    Solving Nuclear Structure Problems with the Adaptive Variational Quantum Algorithm

    A.M. Romero🇺🇸 · J. Engel🇺🇸 · Ho Lun Tang🇺🇸 · Sophia E. Economou🇺🇸

    We use the Lipkin-Meshkov-Glick (LMG) model and the valence-space nuclear shell model to examine the likely performance of variational quantum eigensolvers in nuclear-structure theory. The LMG model exhibits both a phase transition and spontaneous symmetry breaking at the mean-field level in one of the phases, features that characterize collective dynamics in medium-mass and heavy nuclei. We show that with appropriate modifications, the ADAPT-VQE algorithm, a particularly flexible and accurate variational approach, is not troubled by these complications. We treat up to 12 particles and show that the number of quantum operations needed to approach the ground-state energy scales linearly with the number of qubits. We find similar scaling when the algorithm is applied to the nuclear shell model with realistic interactions in the and shells. Although most of these simulations contain no noise, we use a noise model from real IBM hardware to show that for the LMG model with four particles, weak noise has no effect on the efficiency of the algorithm.

    Comments:
    10 pages, 7 figures. Identical in content to published version. Now incudes analysis of noise
    Subjects:
    Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2203.01619 [pdf]
    PRC(2022)·78 citations
  4. 04

    [Submitted on 3 Mar 2022] (cross-list from hep-ph)

    Plutonium-241 as a possible isotope for neutrino mass measurement and capture

    Nicolo de Groot🇳🇱

    Tritium has been the isotope of choice for measurements of the neutrino mass and planned detection of the relic neutrino background. The low mass of H leads to large recoil energy of the nucleus. This has emerged as a limiting factor for both measurements. We investigate Pu as an alternative. The recoil is 80x smaller and it has similar decay energy and lifetime as H. We evaluate for the first time its soft-neutrino capture cross-section and find . This is 40% of the capture cross-section for tritium and makes Pu an interesting alternative for H.

    Comments:
    6 pages, 1 figure
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2203.01708 [pdf]
    J.Phys.G(2023)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE