Factorization of 3‐Point Static Structure Functions in 3D Yukawa Liquids |
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| Authors: | P. Magyar P. Hartmann G.J. Kalman K. I. Golden Z. Donkó |
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| Affiliation: | 1. Institute for Solid State Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H‐1525 Budapest, P.O. Box 49, Hungary;2. Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA;3. Department of Mathematics and Statistics, and Department of Physics, University of Vermont, Burlington, USA |
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| 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. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) |
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| Keywords: | Structure functions response functions molecular dynamics simulation |
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