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Main Authors: Klatt, Michael Andreas, Bair, Christian, Löwen, Hartmut, Wittmann, René
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2304.10526
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author Klatt, Michael Andreas
Bair, Christian
Löwen, Hartmut
Wittmann, René
author_facet Klatt, Michael Andreas
Bair, Christian
Löwen, Hartmut
Wittmann, René
contents When can we map a classical density profile to an external potential? In equilibrium, without time dependence, the one-body density is known to specify the external potential that is applied to the many-body system. This mapping from a density to the potential is the cornerstone of classical density functional theory (DFT). Here, we consider non-equilibrium, time-dependent many-body systems that evolve from a given initial condition. We derive explicit conditions, for example, no flux at the boundary, that ensure that the mapping from the density to a time-dependent external potential is unique. We thus prove the underlying assertion of dynamical density functional theory (DDFT), without resorting to the so-called adiabatic approximation often used in applications. By ascertaining uniqueness for all $n$-body densities, we ensure that the proof and the physical conclusions drawn from it hold for general superadiabatic dynamics of interacting systems even in the presence of (known) non-conservative forces.
format Preprint
id arxiv_https___arxiv_org_abs_2304_10526
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Foundation of classical dynamical density functional theory: uniqueness of time-dependent density-potential mappings
Klatt, Michael Andreas
Bair, Christian
Löwen, Hartmut
Wittmann, René
Mathematical Physics
Soft Condensed Matter
82C03, 82C05
When can we map a classical density profile to an external potential? In equilibrium, without time dependence, the one-body density is known to specify the external potential that is applied to the many-body system. This mapping from a density to the potential is the cornerstone of classical density functional theory (DFT). Here, we consider non-equilibrium, time-dependent many-body systems that evolve from a given initial condition. We derive explicit conditions, for example, no flux at the boundary, that ensure that the mapping from the density to a time-dependent external potential is unique. We thus prove the underlying assertion of dynamical density functional theory (DDFT), without resorting to the so-called adiabatic approximation often used in applications. By ascertaining uniqueness for all $n$-body densities, we ensure that the proof and the physical conclusions drawn from it hold for general superadiabatic dynamics of interacting systems even in the presence of (known) non-conservative forces.
title Foundation of classical dynamical density functional theory: uniqueness of time-dependent density-potential mappings
topic Mathematical Physics
Soft Condensed Matter
82C03, 82C05
url https://arxiv.org/abs/2304.10526