International Workshop on 'New challenges in Reduced Density Matrix Functional Theory: Symmetries, time-evolution and entanglement'

September 26, 2017 to September 29, 2017
Location : CECAM-HQ-EPFL, Lausanne, Switzerland
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Density matrix functionals: existence, uniqueness and applicability

Peter Knowles
Cardiff University, United Kingdom

Coauthor(s) : Jian Wang[2]
[2] Huzhou University, Zhejiang, China


Many popular approximations of the two-electron density matrix are formulated as algebraic functions of the one-electron density matrix, typically in the N-in-N active orbital space. Whilst good accuracy can often be achieved, there are examples of wavefunctions with identical one-electron, but strongly different two-electron density matrices, which mean that algebraic density-matrix functionals cannot be exact everywhere [1]. The implications of this to the design of approximations to the static and dynamic correlation energy are discussed.


[1] J. Wang and P. J. Knowles, Phys. Rev. A 92 012520 (2015).