arXiv subjects

Augusto González

Publications and source records attributed to Augusto González.

3 recordsLinked to original sources

arXiv2022

A new channel for excitonic transport in the FMO complex

We expose a new excitation transport channel in FMO, consisting of the 7 intramonomeric pigments and their 2nd nearest intermonomeric counterpart. Such a channel outcompetes the standard alternative, where intramonomeric pigments partner with their closest intermonomeric pigment. The efficient performance of the new channel lies at the interplay between incoherent energy transfer and the capacity of quantum coherence to build optimal acceptor levels. Finally, the differential fitness and peculiarity of the new over the alternative channel highlights its possible role within natural selection.

physics.chem-ph↗

arXiv2013

Scaling in the correlation energies of two-dimensional artificial atoms

We find an unexpected scaling in the correlation energy of artificial atoms, i.e., harmonically confined two-dimensional quantum dots. The scaling relation is found through extensive numerical examinations including Hartree-Fock, variational quantum Monte Carlo, density-functional, and full configuration-interaction calculations. We show that the correlation energy, i.e., the true ground-state total energy subtracted by the Hartree-Fock total energy, follows a simple function of the Coulomb energy, confimenent strength and, the number of electrons. We find an analytic expression for this function, as well as for the correlation energy per particle and for the ratio between the correlation and total energies. Our tests for independent diffusion Monte Carlo and coupled-cluster results for quantum dots -- including open-shell data -- confirm the generality of the obtained scaling. As the scaling is also well applicable to $\gtrsim$ 100 electrons, our results give interesting prospects for the development of correlation functionals within density-functional theory.

cond-mat.mes-hall↗

arXiv2008

Universality in the Energy Spectrum of Medium-Sized Quantum Dots

In a two-dimensional parabolic quantum dot charged with $N$ electrons, Thomas-Fermi theory states that the ground-state energy satisfies the following non-trivial relation: $E_{gs}/(\hbarω)\approx N^{3/2} f_{gs}(N^{1/4}β)$, where the coupling constant, $β$, is the ratio between Coulomb and oscillator ($\hbarω$) characteristic energies, and $f_{gs}$ is a universal function. We perform extensive Configuration Interaction calculations in order to verify that the exact energies of relatively large quantum dots approximately satisfy the above relation. In addition, we show that the number of energy levels for intraband and interband (excitonic and biexcitonic) excitations of the dot follows a simple exponential dependence on the excitation energy, whose exponent, $1/Θ$, satisfies also an approximate scaling relation {\it a la} Thomas-Fermi, $Θ/(\hbarω)\approx N^{-γ} g(N^{1/4}β)$. We provide an analytic expression for $f_{gs}$, based on two-point Padé approximants, and two-parameter fits for the $g$ functions.

cond-mat.mes-hall↗