Volume 9 Issue 4, April 2013

A class of two-terminal passive circuit elements that can also act as memories could be the building blocks of a form of massively parallel computation known as memcomputing.

A reworking of the theory of particle interactions — the same theory but rendered in a new form based on twistor geometry — is likely to have wide implications for physics, including the reformulation of gravity.

Linking two smoke rings or tying a single ring into a knot is no easy feat. Such topological vortices are now created in water with the aid of specially printed hydrofoils.

Recently developed experimental and theoretical tools uncover the complex and unexpected behaviour of impurities propagating through an ensemble of ultracold atoms.

A snapshot of electrons crossing a metal/organic interface provides a better understanding of spin filtering and hints at new directions for designing spintronic devices.

Introducing connections between two distinct networks can tip the balance of power — at times enhancing the weaker system. The properties of the nodes that are linked together often determine which network claims the competitive advantage.

A magnetometer focused on nitrogen-vacancy centres in diamond can image the magnetic dipole field of a single target electron spin at room temperature and ambient pressure.

When CaFe₂As₂ is lightly doped with Co an electronic liquid-crystalline state emerges, which becomes the ‘parent’ state of high-temperature superconductivity in this ferropnictide. A spectroscopic imaging study shows that the ‘nematic’ order is likely to be an artefact of the doping itself.

Electrons can travel though very pure materials without scattering from defects. In this ballistic regime, magnetic fields can manipulate the electron trajectory. Such magnetic electron focusing is now observed in graphene. Although the effect has previously been seen in metals and semiconductors, it is evident in graphene at much higher temperatures—including room temperature.

Networks competing for limited resources are often more vulnerable than isolated systems, but competition can also prove beneficial—and even prevent network failure in some cases. A new study identifies how best to link networks to capitalize on competition.

Understanding the propagation of spin excitations is a difficult problem in quantum magnetism. Using site-resolved imaging in a one-dimensional atomic gas, it is possible to track the dynamics of a moving spin impurity through the Mott-insulator and superfluid regimes.

Understanding the origin of spin filtering in metal/organic interfaces is important for the control of spin injection in organic semiconductors. A time-resolved photoemission experiment shows that spin filtering can be explained by the trapping of electrons in spin-dependent potentials at the interface.

The efficiency of carrier–carrier scattering in graphene is now experimentally demonstrated. The dominance of this mechanism over phonon-related scattering means that a single high-energy photon could create two or more electron–hole pairs in graphene; an effect useful for optoelectronic applications.

Linking two smoke rings or tying a single ring into a knot is no easy feat. Now, however, such topological vortices are created in water using 3D-printed hydrofoils. High-speed imaging shows how the linked rings spontaneously separate, and the knots are able to free themselves. Similar fluid dynamics may also be relevant in plasmas, quantum fluids and optics.