Time-dependent current density functional theory via time-dependent deformation functional theory: a constrained...

Area of Science:

• Quantum Mechanics
• Computational Chemistry
• Condensed Matter Physics

Background:

• Time-dependent current density functional theory (TDCDFT) is a key method for studying electronic dynamics.
• Existing TDCDFT formulations rely on external potential-to-density/current mappings, which can be complex.
• A recent development, time-dependent deformation functional theory (TDDefFT), offers an alternative perspective.

Purpose of the Study:

• To analyze and reconsider the logical structure and theorems of TDCDFT.
• To explore the advantages of TDDefFT in reformulating TDCDFT.
• To clarify the physical origin and causal structure of universal functionals in TDCDFT.

Main Methods:

• Re-evaluation of TDCDFT using the formalism of TDDefFT.
• Formulation of TDCDFT analogous to the constrained search procedure in ground-state DFT.
• Derivation of fundamental functionals from a constrained many-body problem in a comoving frame.

Main Results:

• TDDefFT provides a method to bypass traditional external potential-to-density/current mappings.
• The new formulation reveals the physical origin and causal structure of universal functionals.
• The approach clarifies the theoretical underpinnings and predictive power of TDCDFT.

Conclusions:

• The TDDefFT perspective offers a more fundamental understanding of TDCDFT.
• This reformulation simplifies the theoretical framework and enhances clarity.
• The study confirms the predictive power of TDCDFT through a rigorous theoretical re-evaluation.