Comment on ``Modifying the variational principle in the action-integral-functional derivation of time-dependent density-functional theory''
Abstract
In a paper recently published in Phys. Rev. A [arXiv:1010.4223], Schirmer has criticized an earlier work of mine [arXiv:0803.2727], as well as the foundations of time-dependent density functional theory. In Ref.[2], I showed that the so-called "causality paradox" - i.e., the failure of the exchange-correlation potential derived from the Runge-Gross time-dependent variational principle to satisfy causality requirements - can be solved by a careful reformulation of that variational principle. Fortunately, the criticism presented in Ref.[1] is based on elementary misunderstandings of the nature of functionals, gauge transformations, and the time-dependent variational principle. In this Comment I wish to point out and clear these misunderstandings.
- Publication:
-
Physical Review A
- Pub Date:
- April 2011
- DOI:
- 10.1103/PhysRevA.83.046501
- arXiv:
- arXiv:1103.5702
- Bibcode:
- 2011PhRvA..83d6501V
- Keywords:
-
- 31.15.E-;
- 71.15.Qe;
- Density-functional theory;
- Excited states: methodology;
- Condensed Matter - Other Condensed Matter
- E-Print:
- 4 pages. Accepted for publication in Phys. Rev. A