MaX paper

The authors present a joint experimental and theoretical characterization of the magnetic properties of coordination clusters with an antiferromagnetic core of four magnetic ions. Two different compounds are analyzed, with Co and Mn ions in the core. While both molecules are antiferromagnetic, they display different sensitivities to external magnetic field, according to the different atomic magnetic moments and strength of the intra-molecular magnetic couplings.

Within density functional theory, the authors have investigated the coalescence dynamics of two superfluid helium nanodroplets hosting vortex lines in different relative orientations, which are drawn towards each other by the Van der Waals mutual attraction. The authors have found a rich phenomenology depending on how the vortex lines are oriented. In particular, when a vortex and antivortex lines are present in the merging droplets, a dark soliton develops at the droplet contact region, which eventually decays into vortex rings.

The authors compute the thermal conductivity of water within linear response theory from equilibrium molecular dynamics simulations, by adopting two different approaches. In one, the potential energy surface (PES) is derived on the fly from the electronic ground state of density functional theory (DFT) and the corresponding analytical expression is used for the energy flux. In the other, the PES is represented by a deep neural network (DNN) trained on DFT data, whereby the PES has an explicit local decomposition and the energy flux takes a particularly simple expression.

The authors present a general method for solving the modified Helmholtz equation without shape approximation for an arbitrary periodic charge distribution, whose solution is known as the Yukawa potential or the screened Coulomb potential. The method is an extension of Weinert’s pseudo-charge method [Weinert M, J Math Phys, 1981, 22:2433–2439] for solving the Poisson equation for the same class of charge density distributions. The inherent differences between the Poisson and the modified Helmholtz equation are in their respective radial solutions.

The origin of the very low luminosity of Uranus is unknown, as is the source of the internal tidal dissipation required by the orbits of the Uranian moons. Models of the interior of Uranus often assume that it is inviscid throughout, but recent experiments show that this assumption may not be justified; most of the interior of Uranus lies below the freezing temperature of H₂O. The authors find that the stable solid phase of H₂O, which is superionic, has a large viscosity controlled by the crystalline oxygen sublattice.

Spin-orbit coupling (SOC) is generally understood as a highly localized interaction within each atom, whereby core electrons holding large J splittings transfer the SOC to the valence electrons of the same atom, while their direct impact on neighbor valence orbitals is usually small. Seivane and Ferrer [Phys. Rev. Lett.

The simulation and analysis of the thermal stability of nanoparticles, a stepping stone towards their application in technological devices, require fast and accurate force fields, in conjunction with effective characterisation methods. In this work, the authors develop efficient, transferable, and interpretable machine learning force fields for gold nanoparticles based on data gathered from Density Functional Theory calculations.

Interference effects in finite sections of one-dimensional moiré crystals are investigated using a Landauer-Büttiker formalism within the tight-binding approximation. The authors explain interlayer transport in double-wall carbon nanotubes and design a predictive model. Wave function interference is visible at the mesoscale: in the strong coupling regime, as a periodic modulation of quantum conductance and emergent localized states; in the localized-insulating regime, as a suppression of interlayer transport, and oscillations of the density of states.

In the GW approximation, the screened interaction W is a nonlocal and dynamical potential that usually has a complex frequency dependence. A full description of such a dependence is possible but often computationally demanding. For this reason, it is still common practice to approximate W(ω) using a plasmon pole (PP) model. Such an approach, however, may deliver an accuracy limited by its simplistic description of the frequency dependence of the polarizability, i.e., of W.

Within density functional theory, we have studied the interplay between vortex arrays and capillary waves in spinning prolate 4He droplets made of several thousand helium atoms. Surface capillary waves are ubiquitous in prolate superfluid 4He droplets, and depending on the size and angular momentum of the droplet, they may coexist with vortex arrays. The authors have found that the equilibrium configuration of small prolate droplets is vortex free, evolving towards vortex hosting as the droplet size increases. This result is in agreement with a recent experiment [O'Connell et al., Phys.