Theoretical method for the study of the excited states of a system

TL;DR

This paper introduces an exact theoretical approach that transforms excited state problems into ground state problems, enabling the use of ground state techniques for excited states and constructing a new density functional for them.

Contribution

It presents a novel method converting excited state analysis into ground state problems and develops a new density functional for excited states.

Findings

Transforms excited state problems into ground state problems

Constructs a new exact density functional for excited states

Enables use of ground state techniques for excited state analysis

Abstract

A novel, exact, theoretical method for the study of the excited states of a system is presented. It is demonstrated how to transform the excited state problem of one Hamiltonian into the ground state problem of an auxiliary one. From this, a new exact density functional suitable for excited states is constructed. These results make the excited states of a system accessible through all ground state theoretical techniques.