NEUTRON CORRELATIONS IN 6He VIEWED THROUGH NUCLEAR BREAK-UP

Nuclear break-up as a tool to study neutron correlations is investigated both theoretically and experimentally. First a time dependent theory going beyond mean field has been developed and shows that correlations between nucleons can be probed through nuclear break-up. Secondly, nuclear break-up of 6 He on 208 Pb target was studied at 20 A.MeV using a secondary beam of 6 He produced by the SPIRAL facility at GANIL. From the correlation function, a strong contribution of the di-neutron configuration of 6 He is found.

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A Perturbation Method for the Classical Time‐Dependent Pair Correlation Function

Journal of Mathematical Physics ◽

10.1063/1.1704970 ◽

1966 ◽

Vol 7 (4) ◽

pp. 589-602 ◽

Cited By ~ 1

Author(s):

Raphael Aronson

Keyword(s):

Correlation Function ◽

Perturbation Method ◽

Pair Correlation Function ◽

Pair Correlation ◽

Time Dependent ◽

Dependent Pair

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The gas-liquid surface of the penetrable sphere model. II

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1978.0009 ◽

1978 ◽

Vol 358 (1694) ◽

pp. 267-280 ◽

Cited By ~ 5

Keyword(s):

Surface Tension ◽

Correlation Function ◽

Liquid Surface ◽

Mean Field ◽

Field Approximation ◽

Mean Field Approximation ◽

Intermolecular Potential ◽

Direct Correlation Function ◽

Sphere Model ◽

One Dimensional

The direct correlation function between two points in the gas-liquid surface of the penetrable sphere model is obtained in a mean-field approximation. This function is used to show explicitly that three apparently different ways of calculating the surface tension all lead to the same result. They are (1) from the virial of the intermolecular potential, (2) from the direct correlation function, and (3) from the energy density. The equality of (1) and (2) is shown analytically at all temperatures 0 < T < T c where T c is the critical temperature; the equality of (2) and (3) is shown analytically for T ≈ T c , and by numerical integration at lower temperatures. The equality of (2) and (3) is shown analytically at all temperatures for a one-dimensional potential.

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On the three-dimensional spatial correlations of curved dislocation systems

Materials Theory ◽

10.1186/s41313-020-00026-w ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Joseph Pierre Anderson ◽

Anter El-Azab

Keyword(s):

Correlation Function ◽

Slip System ◽

Correlation Functions ◽

Mean Field ◽

Coarse Graining ◽

Dislocation Dynamics ◽

Coarse Grained ◽

Spatial Correlation Function ◽

Line System ◽

Dislocation Densities

AbstractCoarse-grained descriptions of dislocation motion in crystalline metals inherently represent a loss of information regarding dislocation-dislocation interactions. In the present work, we consider a coarse-graining framework capable of re-capturing these interactions by means of the dislocation-dislocation correlation functions. The framework depends on a convolution length to define slip-system-specific dislocation densities. Following a statistical definition of this coarse-graining process, we define a spatial correlation function which will allow the arrangement of the discrete line system at two points—and thus the strength of their interactions at short range—to be recaptured into a mean field description of dislocation dynamics. Through a statistical homogeneity argument, we present a method of evaluating this correlation function from discrete dislocation dynamics simulations. Finally, results of this evaluation are shown in the form of the correlation of dislocation densities on the same slip-system. These correlation functions are seen to depend weakly on plastic strain, and in turn, the dislocation density, but are seen to depend strongly on the convolution length. Implications of these correlation functions in regard to continuum dislocation dynamics as well as future directions of investigation are also discussed.

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