News & Views in 2018

Understanding how natural surfaces repel foulants by wrinkling seems like a simple matter of elasticity. But the nonlinear behaviours that emerge from dimensional effects make for some intriguing new physics.

Recent experiments demonstrate that effects arising from quantum geometrical phases and band structure topology can coexist in two-dimensional materials, and can be addressed via optoelectronic experiments.

Applications of spintronics often require angular momentum to be moved from place to place. A possible observation of spin superfluidity may point the way toward the transport of spin angular momentum across an insulating sample with no dissipation or energy loss.

Energy levels in superconducting quantum devices are highly sensitive to charge fluctuations. Generally, this is considered a bug, but new work transforms this sensitivity into the defining feature of a novel device.

Magnetic tweezer measurements have revealed the forces associated with a star-shaped structure responsible for moving the sperm nucleus to the centre of the egg cell following fertilization.

The ideas of topology are breaking ground in origami-based metamaterials. Experiments now show that certain shapes — doughnuts included — exhibit topological bistability, and can be made to click between different topologically stable states.

The first campaign of the largest stellarator ever built, Wendelstein 7-X, has been successful, achieving high electron temperatures and minimal self-generated plasma current. This is very encouraging for future long-pulse, full-power operation.

Many-body quantum systems fail to reach thermalization only under specific circumstances. An analysis now reveals a new, different kind of non-equilibrating dynamics based on the many-body analogue of quantum scars in single-particle quantum chaos.

Bedforms in deserts include both small ripples and sand dunes that can reach tens to hundreds of metres in length — with seemingly little in between. It now looks as though intermediate-sized megaripples do appear if the conditions are just right.

It’s still unclear which problems can be solved by near-term quantum computers that are beyond the reach of their classical counterparts. A new analysis makes a practical assessment of how sampling the output of a quantum circuit leaves supercomputers in the dust.

Streams of motile cells appear in both healthy development and the evolution of tumours. A study of cells under lateral confinement now suggests their activity plays a key role in triggering these flows.

Cells change shape and volume when they divide — not a simple task, especially when they are confined by surrounding tissue. Experiments now reveal that hydrostatic pressure changes generate the pushing forces that cells need to create space for division.

Quantized Majorana conductance is a hallmark of topological superconductors, but its fragility has made it difficult to observe. Device improvements have now enabled its measurement, making everyone eager to see the next step — topological qubits.

Many particles — both fundamental and emergent — carry angular momentum or spin. Experiments have now demonstrated that phonons can transport angular momentum, showing that they may have spin too.

Light can be coupled to sound via Brillouin scattering, but realizing an efficient interaction isn’t trivial. A new type of resonator succeeds in doing so in a macroscopic device — boasting features that better its nanoscale counterparts.

Quantum tomography infers quantum states from measurement data, but it becomes infeasible for large systems. Machine learning enables tomography of highly entangled many-body states and suggests a new powerful approach to this problem.

The folded structure of the human brain is a hallmark of our intelligence — an optimized packing of neurons into a confined space. Similar wrinkling in brain-on-a-chip experiments provides a way of understanding the physics of how this occurs.