Layered ferromagnets are thrilling materials from both a fundamental and technological point of view. VI3 is an interesting example, with a complex magnetism that differentiates it from the first reported Cr based layered ferromagnets. Here, we show in an indirect way through Angle Resolved Photoemission Spectroscopy (ARPES) experiments, the importance of spin-orbit coupling setting the electronic properties of this material. Our light polarized photoemission measurements point to a ground state with a half-filled e'_+- doublet, where a gap opening is triggered by spin-orbit coupling enhanced by electronic correlations.

The formations of charge and lattice orders are generally coupled in charge density wave (CDW) materials and share identical order wave vectors. Although this situation is usually satisfied in a large class of two-dimensional materials, it falls short in describing the so-called CDW-like phase transition in layered tantalum ditelluride (TaTe_{2}), accompanied by anomalous low temperature transport properties and a periodic lattice distortion (PLD). Here we combine angle-resolved photoemission spectroscopy and low energy electron diffraction to directly access the charge and lattice structures in 1T-polytypic TaTe_{2} and study the anomalous phase transition. Our data reveal the presence of a surprising quasi-one-dimensional Fermi surface with nesting (FSN) condition, despite its van der Waals layered structure. We find that the wave vectors of the FSN and PLD are different, suggesting the decoupled formation between charge and lattice orders. These conditions are accompanied by rich footprints in band structure, including Fermi surface suppression, minigaps, and satellite bands. Our results suggest that TaTe_{2} manifests intrinsic mixed dimensionality between its electronic and lattice structure and that the CDW-like phase transition is likely governed by multiple mechanisms. Our work provides routes for forging unconventional CDW phases and charge-lattice entanglement that would otherwise not be available in materials with fixed dimensionality.

The study of quantum phase transitions that are not clearly associated with broken symmetry is a major effort in condensed matter physics, particularly in regard to the problem of high-temperature superconductivity, for which such transitions are thought to underlie the mechanism of superconductivity itself. Here we argue that the putative quantum critical point in the prototypical unconventional superconductor CeCoIn5 is characterized by the delocalization of electrons in a transition that connects two Fermi surfaces of different volumes, with no apparent broken symmetry. Drawing on established theory of f-electron metals, we discuss an interpretation for such a transition that involves the fractionalization of spin and charge, a model that effectively describes the anomalous transport behavior we measured for the Hall effect.

The recent discovery of gravitational waves from stellar-mass binary black holes (BBHs) provided direct evidence of the existence of these systems. These BBHs would have gravitational microlensing signatures that are, due to their large masses and small separations, distinct from single-lens signals. We apply Bayesian statistics to examine the distinguishability of BBH microlensing events from single-lens events under ideal observing conditions, using modern photometric and astrometric capabilities. The parameter space of stellar-mass BBHs is explored to determine what parameter values optimize detectability. Given one year of ideal observations, a source star at the Galactic center, a GW150914-like BBH lens (total mass 65 solar masses, mass ratio 0.8) at half that distance, and an impact parameter of 0.4 Einstein radii, we find that BBH separations down to 0.00682 Einstein radii are detectable. Holding all other parameters constant, impact parameters <= 0.473 Einstein radii result in detectable BBHs with merger times within the Hubble time.