Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Exciton–polaritons, resulting from the light–matter coupling between an exciton and a photon in a cavity, form Bose–Einstein-like condensates above a critical density. Various aspects of the physics of exciton–polariton condensates are now reviewed.
The superconducting energy gap is perhaps the best-known of the spectral gaps in a superconductor, but there are many other types, including density waves and the mysterious pseudogap. This Review Article surveys what angle-resolved photoemission spectroscopy has revealed about the various gaps.
Understanding the physics of two-dimensional materials beyond graphene is of both fundamental and practical interest. Recent theoretical and experimental advances uncover the interplay between real spin and pseudospins in layered transition metal dichalcogenides.
There are good reasons to consider nonlocality to be the defining feature of quantum mechanics, but stronger nonlocal correlations than those predicted by quantum theory could exist, which raises the intriguing question of what lies beyond.
Testing the limits of the quantum mechanical description of nature has become a subject of intense experimental interest. Recent advances in investigating macroscopic quantum superpositions are pushing these limits.
Starting with wave-particle duality, experiments with light have played a major role in the development of quantum theory. Advances in photonic technologies allow for improved tests of quantum complementarity, delayed-choice and nonlocality.
Nematic order in the iron-based superconductors breaks the symmetry between the x and y directions in the Fe plane. Beyond this, however, there is little consensus on how nematic order arises and whether it has an effect on superconductivity. This Review discusses the current theoretical and experimental state of the field.
