### Abstract

In many-body systems the convolution approximation states that the 3-point static structure function, S^{(3)}(k_{1}, k_{2}), can approximately be “factorized” in terms of the 2-point counterpart, S^{(2)}(k_{1}). We investigate the validity of this approximation in 3-dimensional strongly-coupled Yukawa liquids: the factorization is tested for specific arrangements of the wave vectors k_{1} and k_{2}, with molecular dynamics simulations. With the increase of the coupling parameter we find a breakdown of factorization, of which a notable example is the appearance of negative values of S^{(3)}(k_{1,} k_{2}), whereas the approximate factorized form is restricted to positive values. These negative values – based on the quadratic Fluctuation-Dissipation Theorem – imply that the quadratic part of the density response of the system changes sign with wave number. Our simulations that incorporate an external potential energy perturbation clearly confirm this behavior. (

Original language | English |
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Pages (from-to) | 816-829 |

Number of pages | 14 |

Journal | Contributions to Plasma Physics |

Volume | 56 |

Issue number | 9 |

DOIs | |

Publication status | Published - Oct 1 2016 |

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### Keywords

- Structure functions
- molecular dynamics simulation
- response functions

### ASJC Scopus subject areas

- Condensed Matter Physics

### Cite this

*Contributions to Plasma Physics*,

*56*(9), 816-829. https://doi.org/10.1002/ctpp.201500062