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Nuclear Theory·nucl-th

Tuesday·March 14, 2023

10 papers—7 primary·3 cross-listed

All10Primary7Cross-lists3
  1. 01

    Mixing of one-particle-one-hole projected states with the variation after projection wave functions

    Xiao Lu · Zhan-Jiang Lian · Zao-Chun Gao

    In this paper, we study the mixing of one-particle-one-hole projected states with the variation after projection (VAP) wave functions in attempt to improve the approximation of this method. It turns out that when minimizing only the lowest (yrast) energy with given spin and parity, the one-particle-one-hole projected states can not be mixed into the converged VAP wave function, which is very similar to the situation of the Hartree-Fock method. However, if one minimizes the sum of several lowest energies with the same spin and parity, the one-particle-one-hole mixing can make some improvements to the VAP wave functions. We expect such one-particle-one-hole mixing may be useful in the calculations of the low-lying excited states in heavy nuclei with a large model space.

    nucl-thPRC(2023)·3 citations
  2. 02

    Removal of -mixing in angular momentum projected nuclear wave functions

    Xiao Lu · Zhan-Jiang Lian · Zao-Chun Gao

    Angular momentum projection plays a key role in studying quantum many-body systems with rotational invariance such as atomic nuclei. At a given spin , one can generate angular momentum projected states labeled with from a deformed Slater determinant. Usually, a nuclear wave function with -mixing can be expressed as a superposition of all these projected states, where the coefficients can be obtained by solving the generalized eigenvalue equation. In this Letter, we report a new fundamental feature that the frequently discussed -mixing in the angular momentum projected nuclear wave function can be safely removed. Strikingly, we found that such nuclear wave function with -mixing can always be equivalently replaced by a single projected state with any given . Consequently, such nuclear wave function can be significantly simplified, especially for high-spin states. This also indicates that the -mixing in the angular momentum projected nuclear wave functions, adopted by many present-day nuclear models, does not carry any physical meaning, and is essentially different from that -mixing caused by the Coriolis force in the cranked shell model.

    nucl-thPRC(2025)·1 citation
  3. 03

    Finding the best basis states for the variation after projection nuclear wave functions

    Xiao Lu · Zhan-Jiang Lian · Xue-Wei Li · Zao-Chun Gao · Yong-Shou Chen

    The variation after projection (VAP) method is expected to be an efficient way of getting the optimized nuclear wave functions, so that they can be as close as possible to the exact shell model ones. However, we found there are two additional problems that may seriously affect the convergence of the VAP iteration. The first problem is, if a randomly selected projected basis state does not mix with a VAP wave function in the VAP calculation, then it is likely that this basis state will never mix with the VAP wave function even after the VAP iteration converges, which means such selected projected basis state is useless. The other problem is the poor orthonormality among the projected basis states that seriously affect the accuracy of the calculated VAP wave function. In the present work, solutions for these two problems are proposed and some examples are presented to test the validity. It turns out that, with the present solutions, the most important projected basis states can be reliably obtained and the fully optimized VAP wave functions can be accurately and efficiently calculated.

    nucl-thCPC(2023)·4 citations
  4. 04

    Single-Particle Spectra in Relativistic Heavy-Ion Collisions Within the Thermal Quantum Field Theory

    Dmitry Anchishkin🇺🇦

    A quantum generalization of the Cooper-Fry recipe is proposed. The single-particle spectrum arising from relativistic collisions of particles and nuclei is calculated within the thermal quantum field theory framework. The starting point of consideration is the solution of the initial-value problem of particle emission from a space-like hypersurface. In the following steps, we obtain the single-particle spectrum using the ``smaller'' Green's function associated with the fireball medium. Based on this result, several specific examples of particle emission are considered.

    nucl-thhep-phquant-phJ.Phys.G(2022)·1 citation
  6. 06

    Non-radial oscillations and gravitational wave emission of hybrid neutron stars

    Zi-Yue Zheng🇨🇳 · Ting-Ting Sun🇨🇳 · Huan Chen🇨🇳 · Jin-Biao Wei🇨🇳 · G. F. Burgio🇮🇹 · H.-J. Schulze🇮🇹

    We investigate non-radial oscillations of pure and hybrid neutron stars, employing equations of state of nuclear matter from Brueckner-Hartree-Fock theory, and of quark matter from the Dyson-Schwinger quark model, performing a Gibbs construction for the mixed phase in hybrid stars. Characteristic differences between neutron-star and hybrid-star -mode oscillation frequencies, damping times, and gravitational wave strains are pointed out. Prospects of observations are also discussed.

    nucl-thastro-ph.HEgr-qcPRD(2023)·17 citations
  7. 07

    Constraint of the Nuclear Dissipation Coefficient in Fission of Hypernuclei

    J. L. Rodríguez-Sánchez🇪🇸 · J. Cugnon🇧🇪 · J.-C. David🇫🇷 · J. Hirtz🇫🇷 · A. Kelić-Heil🇩🇪 · I. Vidaña🇮🇹

    Experimental studies of nuclear fission induced by fusion, transfer, spallation, fragmentation, and electromagnetic reactions in combination with state-of-the-art calculations are successful to investigate the nuclear dissipation mechanism in normal nuclear matter, containing only nucleons. The dissipation mechanism has been widely studied by the use of many different fission observables and nowadays the dissipation coefficients involved in transport theories are well constrained. However, the existence of hypernuclei and the possible presence of hyperons in neutron stars make it necessary to extend the investigation of the nuclear dissipation coefficient to the strangeness sector. In this Letter, we use fission reactions of hypernuclei to constrain for the first time the dissipation coefficient in hypernuclear matter, observing that this coefficient increases a factor of 6 in presence of a single -hyperon with respect to normal nuclear matter.

    nucl-thPRL(2023)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE