Reviews & Analysis

The pairing of electrons in high-temperature superconductors is anisotropic. Measurements now reveal their scattering to bear the same anisotropy, providing insights into the nature of the normal state and the origin of superconductivity.

Electron spins confined within quantum dots are potential qubits for quantum information processing. But how to couple the dots? Optical probing of spherical structures that contain two concentric coupled quantum dots leads the way.

Quantum networks could permit secure communication over large distances and, eventually, quantum computing with photons. One of the basic building blocks has now been put in place.

Strongly correlated systems are difficult to control or even probe at the level of individual interacting elements. Engineered composites of optical cavities, few-level atoms, and laser light could enable greater insight into their behaviour.

An ultrafast diffractive imaging technique that reconstructs an object's structure from a single short X-ray pulse is an important step towards the superlative spatial and temporal resolution promised by next-generation free-electron lasers.

Quantum information is an active area of physics, but is it also one of long-lasting significance? Judging by the mere elegance of a new approach for handling imperfections in quantum registers, the answer must be 'yes'.

The ability to control the path of optical spatial solitons — non-spreading filaments of light that travel through a bulk nonlinear medium — could aid their use in signal processing and other photonics applications.

Most techniques for slowing light are limited in the delay time that can be achieved relative to the temporal pulse width. The use of gap solitons could help overcome this limitation.

Classically, the second law of thermodynamics implies that our knowledge about a system always decreases. A more flattering interpretation connects entropy with the uncertainty inherent to quantum mechanics.

The process of adsorption and subsequent desorption of gases in porous materials often shows hysteretic behaviour. A combination of diffusion measurements and numerical modelling could now explain why.

Two recent developments suggest how familiar properties of gravity and matter may emerge from the quantum geometry that underlies loop quantum gravity.

The discovery that microfluidic 'crystals' exhibit long-range collective behaviour demonstrates their potential use as a testbed for studying dissipative self-organization and other non-equilibrium phenomena.

The flow behaviour of solid helium at very low temperatures has recently generated as much controversy as excitement. An experiment looking directly at the grain boundaries offers fresh insights.

Atom-waves interferometers are becoming ever more compact. A new way of coherently splitting atom waves, based on radiofrequency fields, could extend the capabilities of these miniature atom traps.

When two one-dimensional Bose–Einstein condensates interfere, they exhibit a fluctuating interference pattern. The full statistical distribution of the interference amplitude can be predicted, thanks to a remarkable connection to several exactly solvable problems.

The combined data from four systems of telescopes offer the strongest evidence yet that a modification of gravity cannot do away with the need for dark matter.

Quantum teleportation in itself is intriguing. But now the combined states of two photons have been teleported — while preserving their entanglement — and this could bring large-scale quantum communication and computation a step closer.

A new kind of X-ray microscopy can visualize single-unit-cell steps on a crystal surface. This is an order of magnitude better depth-resolution than current X-ray microscopes can achieve.