Volume 11 Issue 1, January 2015

Magnetic fields can be used to modify light absorption in chiral media, but the effect is weak, so the potential of this approach has gone largely untapped. Synchrotron radiation may provide a solution, enabling surprisingly strong dichroisms in a molecular helix.

Fractional magnetic excitations naturally emerge in one-dimensional spin chains. The search for fractionalization in higher dimensions has focused on frustrated systems but evidence now suggests that it can occur in simple two-dimensional antiferromagnets.

Light emitted near an optical waveguide is captured and equally split into two modes with opposite directions of propagation. By controlling the dipole spin of the emitter, it is possible to break this symmetry and select only one direction.

Graphene is a candidate spintronics material, but its weak intrinsic spin–orbit coupling is problematic. Intercalating graphene on an iridium substrate with islands of lead is now shown to induce a strong, spatially varying spin–orbit coupling.

Transferring electrons from the ground state to an excited state by optical pumping usually increases the population of the upper state. But for graphene in an external magnetic field, the pumped state actually gets depleted.

Subradiant states have remained elusive since their prediction sixty years ago, but they have now been uncovered in ultracold molecules, where they could prove useful for ultra-high precision spectroscopy.

In 2006, Nature Physics published a paper reporting a Stern–Gerlach effect for dark polaritons and one revealing the existence of slow-light solitons. Both of these papers have significantly advanced the field of slow-light research.

The Nernst coefficient is a measure of the transverse thermoelectric effect in a conductor. Superconducting fluctuations magnify this effect but in URu₂Si₂, the million-fold enhancement suggests that the fluctuations have an exotic origin.

Superconducting vortex droplets in a mesoscopic superconductor disintegrate in the same way as the charged liquid droplets studied by Lord Rayleigh, revealing dynamics similar to thunder clouds, atomic nuclei and trapped ultracold atoms.

Defects are often introduced to increase the stiffness of three-dimensional materials. Evidence now suggests that the elastic modulus of two-dimensional graphene sheets can also be increased by controlled defect creation.

An experimental study characterizes subradiance—inhibited emission due to destructive interference—in ultracold molecules close to the dissociation limit and shows that it could be used for precision molecular spectroscopy.

Many quantum protocols require fast, remote entanglement generation to outperform their classical counterparts. A modular solution is now reported, using trapped ions that are remotely entangled through photons.

Graphene’s electronic properties can be modified by putting it on a substrate. Now it is shown that intercalating a graphene sheet and an iridium substrate with lead islands causes resonances, attributed to a spatial variation of spin–orbit coupling.

Falling droplets bounce back well from superhydrophobic surfaces. Now it is shown that when a thin air film is made to persist between drop and surface, efficient bouncing is possible for wettable surfaces too, and for drops with low surface tension.

Linear resistivity across many strongly correlated materials at high temperatures has no satisfactory explanation. A universal framework of incoherent metallic transport in which quantities are bounded could be the way forward.

Fractional magnetic excitations are thought to exist even in the simplest multi-dimensional spin models, but attention has focused on frustrated systems. Such excitations have now been seen in an unfrustrated two-dimensional quantum antiferromagnet.

Weak magneto-chiral dichroic effects may explain why biomolecules all have the same chirality, but they are notoriously difficult to observe. Using hard X-rays, strong magneto-chiral dichroism has now been observed in a paramagnetic molecular helix.

Landau levels in graphene are not equidistant so that transitions between them can be individually probed. Time-resolved optical pumping experiments reveal strong electron–electron scattering resulting in an Auger-depleted zeroth order Landau level.

Solids embedded with fluid inclusions are intuitively softer than their pure counterparts. But experiments show that when the droplets are small enough, material can become stiffer—highlighting a role for surface tension.

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