Extended Time-Dependent Hartree-Fock Approximation with Particle Collisions

Wong, Cheuk‐Yin; Tang, H.H.K.

doi:10.1103/physrevlett.40.1070

Cited by 149 publications

(58 citation statements)

References 14 publications

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“…In addition, Landau spreading and evaporation damping are well accounted for [23]. However, it does not incorporate the dissipation from two-body mechanisms [24][25][26]. Inclusion of pairing correlations is possible within the time-dependent Hartree-Fock-Bogolyubov theory [27], but realistic applications in three dimensions are not yet achieved.…”

Section: The Time-dependent Hartree-fock Approach a Applicationmentioning

confidence: 99%

Couplings between dipole and quadrupole vibrations in tin isotopes

Simenel¹,

Chomaz²

2009

Phys. Rev. C

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We study the couplings between collective vibrations such as the isovector giant dipole and isoscalar giant quadrupole resonances in tin isotopes in the framework of the time-dependent Hartree-Fock theory with a Skyrme energy density functional. These couplings are a source of anharmonicity in the multiphonon spectrum. In particular, the residual interaction is known to couple the isovector giant dipole resonance with the isoscalar giant quadrupole resonance built on top of it, inducing a nonlinear evolution of the quadrupole moment after a dipole boost. This coupling also affects the dipole motion in a nucleus with a static or dynamical deformation induced by a quadrupole constraint or boost respectively. Three methods associated with these different manifestations of the coupling are proposed to extract the corresponding matrix elements of the residual interaction. Numerical applications of the different methods to 132 Sn are in good agreement with each other. Finally, several tin isotopes are considered to investigate the role of isospin and mass number on this coupling. A simple 1/A dependence of the residual matrix elements is found with no noticeable contribution from the isospin. This result is interpreted within the Goldhaber-Teller model.

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Section: The Time-dependent Hartree-fock Approach a Applicationmentioning

confidence: 99%

Couplings between dipole and quadrupole vibrations in tin isotopes

Simenel¹,

Chomaz²

2009

Phys. Rev. C

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“…In the extended TDHF theory, the evolution of the single particle density matrix ρ(t) is determined by a transport equation [16,18,19,20,21,22,23,24],…”

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confidence: 99%

Finite temperature nuclear response in the extended random phase approximation

1998

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The nuclear collective response at finite temperature is investigated for the first time in the quantum framework of the small amplitude limit of the extended TDHF approach, including a non-Markovian collision term. It is shown that the collision width satisfies a secular equation. By employing a Skyrme force, the isoscalar monopole, isovector dipole and isoscalar quadrupole excitations in 40 Ca are calculated and important quantum features are pointed out. The collisional damping due to decay into incoherent 2p-2h states is small at low temperatures but increases rapidly at higher temperatures.

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“…(II.4) in the strict adiabatic limit. Adiabaticity is broken most prominently at level crossings and the need for surface-hoping has been advocated for a long time in literature [34,[38][39][40]. By solving Eqs.…”

Section: Discussionmentioning

confidence: 99%

“…The need to go beyond the simple TDHF framework has been argued in nuclear theory for quite sometime, see Refs. [38][39][40]: in the role of the zero-point oscillations of the nuclear shape [38], in the role of two-body collisions in affecting the meanfield behavior and leading to thermalization of the single-particle dynamics [39], and the need to extend in some ways the meanfield approach in order to allow for the fluctuations of the single-particle properties [40]. While apparently these extensions of the meanfield approximation appear physically well founded and the agreement with experiment is most of the time satisfactory (partially due to the existence of an appropriate set of fitting parameters), the formal argumentation is somewhat lacking.…”

Section: B Time-dependent Density Functional Theory Approach Its Limmentioning

confidence: 99%

The long journey fromab initiocalculations to density functional theory for nuclear large amplitude collective motion

Bulgac

2010

J. Phys. G: Nucl. Part. Phys.

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At present there are two vastly different ab initio approaches to the description of the the manybody dynamics: the Density Functional Theory (DFT) and the functional integral (path integral) approaches. On one hand, if implemented exactly, the DFT approach can allow in principle the exact evaluation of arbitrary one-body observable. However, when applied to Large Amplitude Collective Motion (LACM) this approach needs to be extended in order to accommodate the phenomenon of surface-hoping, when adiabaticity is strongly violated and the description of a system using a single (generalized) Slater determinant is not valid anymore. The functional integral approach on the other hand does not appear to have such restrictions, but its implementation does not appear to be straightforward endeavor. However, within a functional integral approach one seems to be able to evaluate in principle any kind of observables, such as the fragment mass and energy distributions in nuclear fission. These two radically approaches can likely be brought brought together by formulating a stochastic time-dependent DFT approach to many-body dynamics. We know a great deal by now about interactions between nucleons, although one might rightly argue that the link to quarks and gluons through the more fundamental theory Quantum Chromodynamics has not yet been fully established. It will still be a long time until this goal will be reached with the needed degree of accuracy and sophistication. In this respect the nuclear many-body theory is at a great disadvantage when compared to condensed matter and atomic theories or chemistry, where the dominant role of the Coulomb interaction and the link to Quantum Electrodynamics were clarified a long time ago. There is a general consensus by now however, that in order to describe nuclear many-body systems one probably can get away with the use of one set or another of reasonably well established two-and three-nucleon potentials (if only one would manage to use them in a convincing implementation) and that a non-relativistic approach is likely sufficient for now. The best example we have so far that such an ab initio approach can be brought to fruition is the Green Function Monte-Carlo (GFMC) approach implemented so successfully by V.R. Pandharipande and his many students and collaborators J. Carlson (truly the author of GFMC), S.C. Pieper, R. Schiavilla, K.E. Schmidt, R.B. Wiringa, and many others [1]. One of the most frustrating limitations of the GFMC approach is the relatively low particle number this method can deal with. Presently one cannot envision the study of nuclei heavier than oxygen within a GFMC framework. The Coupled-Cluster (CC) method [2] looks very promising in this respect, as it might be applied to medium size closed shell nuclei in the near future. The No-Core-Shell Model (NCSM) [3] will likely be successfully applied to light and medium size nuclei in the foreseeable future with a reasonable degree of accuracy.Heavy-nuclei seem out of reach from a direct frontal ab initio attack and th...

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Extended Time-Dependent Hartree-Fock Approximation with Particle Collisions

Cited by 149 publications

References 14 publications

Couplings between dipole and quadrupole vibrations in tin isotopes

Couplings between dipole and quadrupole vibrations in tin isotopes

Finite temperature nuclear response in the extended random phase approximation

The long journey fromab initiocalculations to density functional theory for nuclear large amplitude collective motion

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