Articles in 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.

Emotions run high as the European Commission's ambitious framework for research and development forms the focus of a special budget summit in Brussels.

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.

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.

Many-particle entangled states and entanglement between continuous properties are valuable resources for quantum information, but are notoriously difficult to generate. An experiment now entangles the energy and emission times of three photons, creating generalized Einstein–Podolsky–Rosen correlations.

Liquid water expands when heated — or cooled — away from a particular temperature that increases when the fluid is stretched. Experiments on water under extreme tension now enable tracking of this distinctive behaviour well into the negative-pressure domain.

The electronic properties of graphene are spatially controlled from metallic to semiconducting by patterning steps into the underlying silicon carbide substrate. This bottom-up approach could be the basis for integrated graphene electronics.

Photonic crystals efficiently control wave propagation on a wavelength scale, but this means they can become very large when long wavelengths are involved. Metamaterials made of resonant unit cells can confine and guide waves even at scales far below their wavelength.

Different experimental probes have found different bosonic modes in the iron-based superconductors. A scanning tunnelling spectroscopy study of two separate superconductors now links the tunnelling mode with the ‘neutron resonance’, both of which vanish when superconductivity disappears.

Liquid water inclusions in quartz can withstand negative pressures in excess of −100 MPa. Other techniques report much lower thresholds—suggesting that water in inclusions is stabilized by impurity effects. Experiments on a single inclusion in quartz now provide evidence consistent with a homogeneous mechanism for cavitation.

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.