Volume 12 Issue 5, May 2016

The dynamics of a viscous liquid undergo a dramatic slowdown when it is cooled to form a solid glass. Recognizing the structural changes across such a transition remains a major challenge. Machine-learning methods, similar to those Facebook uses to recognize groups of friends, have now been applied to this problem.

Living systems are constantly being driven out of equilibrium by consuming energy. Studying fluctuations can tell us how they do so while maintaining order — and what this teaches us about non-equilibrium processes in general.

Fusion power is one of a very few sustainable options to replace fossil fuels as the world's primary energy source. Although the conditions for fusion have been reached, much remains to be done to turn scientific success into commercial electrical power.

Fusion research is driven by the applied goal of energy production from fusion reactions. There is, however, a wealth of fundamental physics to be discovered and studied along the way. This Commentary discusses selected developments in diagnostics and present-day research topics in high-temperature plasma physics.

Energy-producing nuclear fusion reactions taking place in tokamaks cause radiation damage and radioactivity. Remote-handling technology for repairing and replacing in-vessel components has evolved enormously over the past two decades — and is now being deployed elsewhere too.

Construction of the ITER tokamak, arguably the largest scientific project ever, is well under way in the south of France. Nature Physics spoke with ITER's Director-General, Bernard Bigot, about the challenges ahead — a conversation about physics, engineering, politics and culture.

One way of realizing controlled nuclear fusion reactions for the production of energy involves confining a hot plasma in a magnetic field. Here, the physics of magnetic-confinement fusion is reviewed, focusing on the tokamak and stellarator concepts.

Simulating magnetically confined fusion plasmas is crucial to understand and control them. Here, the state of the art and the multi-physics involved are discussed: electromagnetism and hydrodynamics combined over vast spatiotemporal ranges.

For achieving proper safety and efficiency of future fusion power plants, low-activation materials able to withstand the extreme fusion conditions are needed. Here, the irradiation physics at play and fusion materials research is reviewed.

The quest for energy production from controlled nuclear fusion reactions has been ongoing for many decades. Here, the inertial confinement fusion approach, based on heating and compressing a fuel pellet with intense lasers, is reviewed.

A simulation method connects single-shot measurements in ultracold atom experiments to the probability distribution of the many-body wavefunction, elucidating the role of the fluctuations in different experimental situations.

Interlayer transport can be made to occur slower or faster than intralayer scattering in van der Waals heterostructures, allowing the thermalization pathways for optically excited carriers to be tuned.

Quantum mechanics sets a fundamental upper limit for the flow of heat. Such quantum-limited heat conduction is now observed over macroscopic distances, extending to a metre, in superconducting transmission lines.

Exotic theories predict the violation of Lorentz symmetry, which could potentially be spotted in low-energy experiments. Using ytterbium ions could improve the current sensitivity bounds by five orders of magnitude.

The relation between structure and dynamics in glasses is not fully understood. A new approach based on machine learning now reveals a correlation between softness—a structural property—and glassy dynamics.

Mechanical communication between cells is revealed in experiments on cardiac cells. Deformation of an underlying substrate induces beating in isolated cells, at a rate that can be sustained for over an hour after the stimulation ceases.

Knots have been observed in a variety of classical systems, but so far not in the quantum regime. Knot solitons have now been created in a spinor Bose–Einstein condensate, exhibiting interesting topological structures, including Hopf fibration.

The electronic properties of oxide interfaces are renowned for their richness. A comprehensive study of a series of perovskite nickelates examines the interplay between charge transfer and hybridization effects.

A combination of neutron scattering, X-ray scattering and Mössbauer spectroscopy experiments reveal the existence of a collinear double-Q magnetic ordering in an iron arsenide superconductor.

Fast-ignition laser fusion involves directing an intense relativistic electron beam onto a fuel target. Experiments and simulations now enable a visualization of the location of fast electrons and the energy-coupling mechanisms at play.

Shining intense laser light onto a thin aluminium foil creates a relativistic plasma aperture—and diffraction. As a result, an electron beam is generated with a spatial structure that can be changed by varying the characteristics of the laser pulse.

The membranes of red blood cells exhibit a flickering motion that has long been ascribed a thermal origin. Microrheology experiments provide direct evidence that flickering is an active process characterized by non-equilibrium dynamics.

Enrico Massa and Giovanni Mana expound on the substance of the Avogadro constant.