Physical phenomena at the nanoscale can be considerably different from the behavior in the macroscopic world. This rule is also true for plasmas at the nanoscale. This Colloquium discusses nanoplasmas from the experimental and theoretical point of view and shows that nanoplasmas can also have applications in certain technological areas.

Besides being fundamental for life on Earth, water is one of the complex materials in nature. Due to the unusual properties of the hydrogen bonds water has a large number of phases as a function of temperature and pressure. Furthermore, the phase transitions between these different phases are still the object of much discussion. In this Colloquium the nature of these amazing properties of water is reviewed.

Originally developed for quantum chromodynamics at strong coupling, lattice approximations provide an essential tool applicable to any strongly coupled gauge theory. The resolution of the lightweight Higgs puzzle may require new strongly coupled gauge theories at shorter distances. This review introduces the modern lattice tool kit as a combination of analytical and numerical techniques. Numerous applications to new physics with strong coupling gauge theories are presented, and results analyzed.

The quantum mechanics of black holes, and particularly the information paradox, have been a crucial arena for testing theories of quantum gravity. This review covers the quantum physics of black holes, anti-de Sitter/conformal field theory duality and holography, and the recent firewall paradox, with a focus on ideas from quantum information theory.

Methods of measuring the energies of jets have relied on detection of photons, charged hadrons, and neutral hadrons in a sampling calorimeter. However, the response for each particle is different, leading to poor jet energy resolution. Improved energy resolution for future studies of Higgs bosons and new particles decaying to jets requires improved energy resolution. The particle flow algorithm recognizes that charged particle momenta are better measured than their energies, so considerable improvement in energy resolution can be made using track momenta and substituting the energy deposited in the calorimeter. This article describes beam tests of the particle flow algorithm and the confrontation of data and simulations.

How do we understand the production of the lightest nuclides from H to Li during the first seconds of cosmic time? This article reviews recent developments based on new precision cosmic microwave background measurements from the Planck satellite and observational abundance data. Utilizing updated input on nuclear reactions and the neutron lifetime as well as limits on the baryon density of the Universe obtained from Planck data leads to a number of neutrino flavors.

Wave-particle duality lies at the root of quantum mechanics and is central in the description of interferences observed with elementary objects. In a delayed-choice experiment, the decision to observe the particle or wave character of a quantum system is delayed with respect to the time at which the system enters the interferometer. This paper reviews the history of the delayed-choice idea, introduced as a challenge to a realistic explanation of the wave-particle duality. It also describes recent experimental realizations of this idea and discusses intriguing extensions, such as the duality between separability and entanglement in multiple quantum systems.

The advent of x-ray free electron lasers has made possible the study of matter at the characteristic space and time scales of atomic and molecular phenomena using intense coherent x-ray pulses. This article describes the physical principles and the theoretical models governing the interaction of charged particles, electromagnetic waves, and external magnetic fields that comprise the x-ray free-electron lasers. It also includes a discussion of existing facilities and avenues for increasing the peak power and improving the control of spectral and coherence properties to allow the exploration of an even larger range of phenomena.​

In the five years since achieving first light at the Linac Coherent Light Source, transformative studies have been conducted in a new regime with femtosecond pulses of short wavelength, high intensity x rays. This article summarizes these results in atomic, molecular and optical physics; condensed matter physics; matter in extreme density, temperature and pressure conditions; chemistry and soft matter; and biological structure and dynamics. In each of these areas, perspectives for future research are discussed.

In magnetic fusion reactors relying on the burning of deuterium and tritium, sufficient confinement of the alpha particles produced in the nuclear reactions is crucial to sustaining the burning plasma. In this article the interactions of these energetic particles with linear and nonlinear Alfve’n waves generated in the magnetized plasma are reviewed.