Dissipation dynamics and spin-orbit force in time-dependent Hartree-Fock theory

Dai, Gao-Feng; Guo, Lu; Zhao, En-Guang; Zhou, Shan‐Gui

doi:10.1103/physrevc.90.044609

Cited by 51 publications

(29 citation statements)

References 77 publications

(116 reference statements)

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“…With recently developed symmetry unrestricted codes, LACM with arbitrary shapes [18][19][20][21][22][23][24][25][26] can be described including one-body dissipation as well as particle evaporation. As noted in [27], it can describe the average kinetic energy of fragments after fission.…”

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confidence: 99%

Microscopic Phase-Space Exploration Modeling ofFm258Spontaneous Fission

2017

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We show that the total kinetic energy (TKE) of nuclei after the spontaneous fission of 258 Fm can be well reproduced using simple assumptions on the quantum collective phase-space explored by the nucleus after passing the fission barrier. Assuming energy conservation and phase-space exploration according to the stochastic mean-field approach, a set of initial densities is generated. Each density is then evolved in time using the nuclear time-dependent density-functional theory with pairing. This approach goes beyond mean-field by allowing spontaneous symmetry breaking as well as a wider dynamical phase-space exploration leading to larger fluctuations in collective space. The total kinetic energy and mass distributions are calculated. New information on the fission process: fluctuations in scission time, strong correlation between TKE and collective deformation as well as pre-scission particle emission, are obtained. We conclude that fluctuations of TKE and mass are triggered by quantum fluctuations.PACS numbers: 21.60. Jz, 24.75.+i, 25.85.Ca, 27.90.+b The dynamical modeling of a nuclear Fermi quantum droplet that spontaneously breaks into two pieces represents one of the most exciting challenges of nuclear physics today. Beside its description, a deeper microscopic understanding of spontaneous fission (SF) is of great importance to form the heaviest elements at the frontier of the nuclear chart [1][2][3] or to further improve our knowledge about the competition between the r-process and fission during the primordial nucleosynthesis [4]. Motivated also by its importance in nuclear energy production, intensive experimental efforts have been made to accumulate precise measurements [5][6][7][8][9]. In recent years, an increasing effort was made to remove empirical ingredients that are employed in macroscopic modeling of fission and use microscopic theories [10,11]. The nuclear Density Functional Theory (DFT) is a suitable starting point to describe some aspects related to the large amplitude collective motion (LACM). A minimal information obtained from DFT is the adiabatic collective energy landscape [11]. One challenge to describe spontaneous fission (SF) is the necessity to explicitly treat the evolution as a quantum dynamic in collective space. Progresses have been made with the Time-Dependent Generator Coordinate Method (TDGCM) [12][13][14]. This theory by treating quantally collective degrees of freedom (DOF) is promising. However, the adiabatic assumption often made becomes critical especially close to scission [15]. Dissipation of the collective motion into internal excitations also plays a key role to understand the excitation energy and kinetic energy sharing during fragments separation [16]. Understanding this dissipation requires to include many-body states beyond the adiabatic limit [17]. It is yet unclear how the pre-scission neutron and proton emissions can be incorporated in the TDGCM.The nuclear time-dependent DFT (TDDFT) overcomes some of these limitations. With recently developed symmetry unrest...

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confidence: 99%

Microscopic Phase-Space Exploration Modeling ofFm258Spontaneous Fission

2017

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“…As the theory deals with the single-particle wave functions of nucleons, not only dynamic effects such as nucleon transfer and internal excitations, but also structural effects such as static/dynamic shell effects and shape evolution are naturally incorporated into the description. The spin-orbit coupling is known to play an important role in energy dissipation processes in heavy-ion reactions [108][109][110][111]. The effects of the tensor term on nuclear dynamics were also investigated recently [102,[112][113][114][115].…”

Section: The Tdhf Theorymentioning

confidence: 99%

TDHF Theory and Its Extensions for the Multinucleon Transfer Reaction: A Mini Review

Sekizawa

2019

Front. Phys.

105

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Time-dependent Hartree-Fock (TDHF) theory has been a powerful tool in describing a variety of complex nuclear dynamics microscopically without empirical parameters. In this contribution, recent advances in nuclear dynamics studies with TDHF and its extensions are briefly reviewed, along the line with the study of multinucleon transfer (MNT) reactions. The latter lies at the core of this Research Topic, whose application for production of extremely neutron-rich nuclei has been extensively discussed in recent years. Having in mind the ongoing theoretical developments, it is envisaged how microscopic theories may contribute to the future MNT study. 1 Here a local EDF (like Skyrme) has been assumed, which makes the TDHF equations (1) local in space, as it is currently used in most of practical applications. In general, E = E(r)dr is composed of various local densities, ξ ≡ {ρ, τ, . . . }, and the TDHF equations (1)In such a case, the single-particle Hamiltonian can have spin dependence as well as differential operators (for the explicit form, see, e.g., Refs. [27][28][29]).

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“…The main shortcoming of empirical CC approaches is the choice of the distribution function of barriers which are responsible for couplings of relative motion to intrinsic degrees of freedom. In most of the empirical CC approaches, the barrier distribution has only one maximum, while the experimental barrier distributions extracted from the capture excitation functions, i. been also used to explore the fusion dynamics [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. In recent years, Sargsyan et al developed a quantum diffusion approach [66][67][68] for describing the capture process, which is based on the quantum master equation for the reduced density matrix.…”

Section: Introductionmentioning

confidence: 99%

Systematics of capture and fusion dynamics in heavy-ion collisions

Wang

Wen

Zhao

et al. 2017

Atomic Data and Nuclear Data Tables

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We perform a systematic study of capture excitation functions by using an empirical coupled-channel model. In this model, a barrier distribution is used to take effectively into account the effects of couplings between the relative motion and intrinsic degrees of freedom. The shape of the barrier distribution is of an asymmetric Gaussian form. The effect of neutron transfer channels is also included in the barrier distribution. Based on the interaction potential between the projectile and the target, empirical formulas are proposed to determine the parameters of the barrier distribution.Theoretical estimates for barrier distributions and calculated capture cross sections together with experimental cross sections of 220 reaction systems with 182 Z P Z T 1640 are tabulated. The results show that our empirical formulas work quite well in the energy region around the Coulomb barrier. This model can provide prediction of capture cross sections for the synthesis of superheavy nuclei as well as valuable information on capture and fusion dynamics.

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Dissipation dynamics and spin-orbit force in time-dependent Hartree-Fock theory

Cited by 51 publications

References 77 publications

Microscopic Phase-Space Exploration Modeling ofFm258Spontaneous Fission

Microscopic Phase-Space Exploration Modeling ofFm258Spontaneous Fission

TDHF Theory and Its Extensions for the Multinucleon Transfer Reaction: A Mini Review

Systematics of capture and fusion dynamics in heavy-ion collisions

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