James Brown's research while affiliated with Dartmouth College and other places

Publications (6)

Article
Full-text available
Quantum algorithms are touted as a way around some classically intractable problems such as the simulation of quantum mechanics. At the end of all quantum algorithms is a quantum measurement whereby classical data is extracted and utilized. In fact, many of the modern hybrid-classical approaches are essentially quantum measurements of states with s...
Article
One route to numerically propagating quantum systems is time-dependent density functional theory (TDDFT). The application of TDDFT to a particular system’s time evolution is predicated on V-representability which we have analyzed in a previous publication. Here we describe a newly developed solver for the scalar time-dependent Kohn-Sham potential....
Preprint
Full-text available
Quantum algorithms are touted as a way around some classically intractable problems such as the simulation of quantum mechanics. At the end of all quantum algorithms is a quantum measurement whereby classical data is extracted and utilized. In fact, many of the modern hybrid-classical approaches are essentially quantum measurements of states with s...
Article
There are many ways to numerically represent chemical systems in order to compute their electronic structure. Basis functions may be localized in real-space (atomic orbitals), in momentum-space (plane waves), or in both components of phase-space. Such phase-space localized basis functions in the form of wavelets have been used for many years in the...
Preprint
One route to numerically propagating quantum systems is time-dependent density functional theory (TDDFT). The application of TDDFT to a particular system's time evolution is predicated on $V$-representability which we have analyzed in a previous publication. Here we describe a newly developed solver for the scalar time-dependent Kohn-Sham potential...
Preprint
There are many ways to numerical represent of chemical systems in order to compute their electronic structure. Basis functions may be localized either in real-space (atomic orbital), localized in momentum-space (plane waves), or may be local in both components of phase-space. Such phase-space localized basis functions in the form of wavelets, have...

Citations

... The same methodology can be applied to both the groundstate and time-dependent reverse-engineering problems, however the former requires iterative solutions of the time-independent Kohn-Sham equations, whereas the latter requires repeated iterative application of the time-evolution operator to the Kohn-Sham states. A number of iterative algorithms have been proposed in recent literature to realise the inverse density-to-potential map in time-dependent and ground-state DFT [224][225][226][227][228][229]. For example, some of these approaches consider iterative schemes derived from the continuity equation of time-dependent DFT [225,226], whereas the original timedependent reverse-engineering algorithm in iDEA utilised iterative updates of the vector potential in the context of time-dependent current DFT (matching the current densities) [218]. ...