Research articles

The relaxation mechanisms of isolated quantum many-body systems are insufficiently understood, but a one-dimensional quantum gas experiment uncovers the local emergence of thermal correlations and their cone-like propagation through the system.

Measurements of the spin heat accumulation at the ferromagnetic/non-magnetic interface in nanopillar spin valves show that spin-up and spin-down electrons have different temperatures. This observation is important for the design of magnetic thermal switches and the study of inelastic spin scattering.

The Kibble–Zurek mechanism describes the spontaneous formation of defects in systems that are undergoing a second-order phase transition at a finite rate. Familiar to cosmologists and condensed matter physicists, this mechanism is now found to be responsible for the spontaneous creation of solitons in a Bose–Einstein condensate.

Models for the topology or dynamics of various networks abound, but until now, there has been no single universal framework for complex networks that can separate factors contributing to the topology and dynamics of networks across biological and social systems.

A quantum gas trapped in an optical lattice of triangular symmetry can now be driven from a paramagnetic to an antiferromagnetic state by a tunable artificial magnetic field.

The interface between two non-magnetic band insulators, LaAlO₃ and SrTiO₃, can exhibit conductivity, superconductivity and magnetism. These interfacial phenomena can be reconciled by a theory that predicts a spiral magnetic ground state.

Networks of networks are vulnerable: a failure in one sub-network can bring the rest crashing down. Previous simulations have suggested that randomly positioned networks might offer some limited robustness under certain circumstances. Analysis now shows, however, that real-world interdependent networks, where nodes are positioned according to geographical constraints, might not be so resilient.

Ensembles of nuclear spins display thermal fluctuations—spin noise—that interfere with nuclear magnetic resonance measurements of samples below a threshold size. Experiments on nanowires show that by monitoring spin noise in real time and applying instantaneously adjusted radiofrequency pulses, spin polarization distributions that are narrower than the thermal distribution can be obtained.

The interaction between light and a relativistic electron beam can be used to generate optical vortices in a free electron laser, providing a way to engineer bright orbital angular momentum light at shorter X-ray wavelengths.

The fluctuation relations are a central concept in thermodynamics at the microscopic scale. These relations are experimentally verified by measuring the entropy production in a single-electron box coupled to two heat baths.

Strongly interacting condensed-matter systems are often computationally intractable. By introducing a periodic lattice to a holographic model developed by string theorists, it becomes possible to study anisotropic materials that are insulating in certain directions but conducting in others.

A study of an actomyosin active gel now demonstrates the importance of the crosslinking density of actin polymers in enabling myosin motors to internally drive contraction and rupture the network into clusters. These results could help us to better understand the role of the cytoskeleton in cell division and tissue morphogenesis.

Experimentally verifying that quantum states are indeed entangled is not always straightforward. With the recently proposed device-independent entanglement witnesses, genuine multiparticle entanglement of six ions has now been demonstrated.

Patchy colloidal systems consist of particles with attractive patches on them. If the bonds between particles are allowed to be flexible, a colloidal liquid state may be observed as the system approaches zero temperature.

Charge noise and spin noise lead to decoherence of the state of a quantum dot. A fast spectroscopic technique based on resonance fluorescence can distinguish between these two deleterious effects, enabling a better understanding of how to minimize their influence.

A Wigner molecule—a localized pair of interacting electrons—is now created in a carbon nanotube. The high-quality, electronically pristine tubes enable a full characterization of the energy spectrum, laying the groundwork for future studies of interacting fermion systems in one and two dimensions.

A magnetic field can lift the spin degeneracy of electrons. This Zeeman effect is an important route to generating the spin polarization required for spintronics. It is now shown that such polarization can also be achieved without the need for magnetism. The unique crystal symmetry of tungsten selenide creates a Zeeman-like effect when a monolayer of the material is exposed to an external electric field.

Schrodinger’s cat paradox embodies the open question of whether quantum effects can survive at macroscopic scales. A quantum optics experiment explores this question by creating entanglement between a microscopic and a macroscopic system.

Does quantum theory still apply at macroscopic scales? Looking for new insights into this open problem, an experiment in the spirit of Schroedinger’s cat gedanken experiment investigates the entanglement between microscopic and macroscopic domains.

In topological insulators, studies have largely concentrated on the spin part of the wavefunction. But the spin–orbit coupling is strong, so the orbital components of the wavefunction need to be measured as well. Surprisingly, the orbital wavefunction turns out to be asymmetric about the Dirac point.