Volume 8 Issue 12, December 2012

As the 2012 celebration of Turing's life and work draws to a close, we highlight different events that showcase Turing's continuing influence on science, technology and art.

Hyper-transport — an increase in diffusion beyond the ballistic-transport regime — is observed in an optical system.

Magnets built of molecular rings of magnetic ions are fundamental model systems for studying the complex correlations and dynamics of quantum spins at the atomic scale. A new generation of neutron spectrometers can reveal complete four-dimensional maps of the spin correlations in spin rings.

Answers to fundamental questions about the nature of non-locality shed new light onto the spacetime structure and the role of causality in quantum theory, topics that have traditionally been studied within the quantum gravity community.

An investigation of Coulomb drag in graphene integrated into a stacked heterostructure unveils unexpected electron–hole symmetry-breaking in two-dimensional electronic crystals.

Quantum spin liquids have long eluded detection, despite nearly forty years of investigation. Now, a topological property unique to the quantum-spin-liquid state has emerged as a viable method of detection.

The discovery of charge-density-wave order in the high-temperature superconductor YBa₂Cu₃O_6+y places charge order centre stage with superconductivity, suggesting that they are intertwined rather than competing.

Non-local quantum correlations between distant particles cannot be explained by signals propagating slower than the speed of light. It is now shown that they cannot be explained by hidden influences propagating faster than the speed of light either, because that would permit faster-than-light communication.

X-ray diffraction experiments reveal that spatial charge ordering occurs in the pseudogap state of YBa₂Cu₃O_6.67. Moreover, this charge ordered state competes with high-temperature superconductivity, and their relative strengths can be tuned using a magnetic field.

Current shot-noise for a relativistic electron beam—proportional to the average current and frequency bandwidth of the beam—can be suppressed below the shot-noise limit at optical frequencies, through the exploitation of collective Coulomb interactions.

Fast particles propagating through a classical medium give rise to shock waves. Calculations now uncover the surprising behaviour of particles in one-dimensional quantum fluids: a fast particle will never come to a full stop, and a supersonic particle will propagate through the medium undergoing long-lived oscillations.

New data, backed up by simulations, support the existence of Majorana fermions in the one-dimensional topological superconductor that is induced by placing an aluminium superconductor close to an indium-arsenide nanowire.

Two closely spaced two-dimensional systems can remain strongly coupled by electron–electron interactions even though they cannot physically exchange particles. Coulomb drag is a manifestation of this interaction—in which an electric current passed through one layer causes frictional charge flow in the other—now experimentally observed in bilayer graphene

Topological entanglement entropy provides a robust measure for detecting the long-range entanglement that characterizes quantum ground states displaying topological order. A new method for calculating this entropy isolates minimally entangled states from the ground states of a topological phase—offering a reliable test for identifying topological spin liquids.

Understanding the spin dynamics in magnetic nanostructures is important for spintronics, but so far it has been impossible to probe the spin dynamics directly. A neutron-scattering technique providing direct information about dynamical two-spin correlations in a molecular nanomagnet has now been demonstrated.

An increase in diffusion beyond the ballistic-transport regime is now demonstrated. This so-called hyper-transport is observed in an optical experiment, but it might also be evident in other systems with time-varying disorder.

Enhanced control of the nuclear spin orientation of rare isotopes has now been demonstrated. This technique is considerably more efficient than traditional methods and significantly broadens the domain of accessible nuclei, promising insights in nuclear physics and applications in material science.

A super-elastic collision is one that results in an increase of kinetic energy in the colliding system. A probable occurrence of such a collision is shown in the huge, magnetized plasmas of two coronal mass ejections from the Sun.