  Quantum phenomena are typically observable at length and time scales smaller
than those of our everyday experience, often involving individual particles or
excitations. The past few decades have seen a revolution in the ability to
structure matter at the nanoscale, and experiments at the single particle level
have become commonplace. This has opened wide new avenues for exploring and
harnessing quantum mechanical effects in condensed matter. These quantum
phenomena, in turn, have the potential to revolutionize the way we communicate,
compute and probe the nanoscale world. Here, we review developments in key
areas of quantum research in light of the nanotechnologies that enable them,
with a view to what the future holds. Materials and devices with nanoscale
features are used for quantum metrology and sensing, as building blocks for
quantum computing, and as sources and detectors for quantum communication. They
enable explorations of quantum behaviour and unconventional states in nano- and
opto-mechanical systems, low-dimensional systems, molecular devices,
nano-plasmonics, quantum electrodynamics, scanning tunnelling microscopy, and
more. This rapidly expanding intersection of nanotechnology and quantum
science/technology is mutually beneficial to both fields, laying claim to some
of the most exciting scientific leaps of the last decade, with more on the
horizon.
