A Rydberg atom is an excited atom with one or more electrons that have a very high principal quantum number, n. The higher the value of n, the farther the electron is from the nucleus, on average. Rydberg atoms have a number of peculiar properties including an exaggerated response to electric and magnetic fields, long decay periods and electron wavefunctions that approximate, under some conditions, classical orbits of electrons about the nuclei. The core electrons shield the outer electron from the electric field of the nucleus such that, from a distance, the electric potential looks identical to that experienced by the electron in a hydrogen atom.
Plasma acceleration is a technique for accelerating charged particles, such as electrons, positrons, and ions, using the electric field associated with electron plasma wave or other high-gradient plasma structures. The plasma acceleration structures are created either using ultra-short laser pulses or energetic particle beams that are matched to the plasma parameters. These techniques offer a way to build high performance particle accelerators of much smaller size than conventional devices. The basic concepts of plasma acceleration and its possibilities were originally conceived by Toshiki Tajima and John M. Dawson of UCLA in 1979. The initial experimental designs for a "wakefield" accelerator were conceived at UCLA by Chandrashekhar J. Joshi et al. Current experimental devices show accelerating gradients several orders of magnitude better than current particle accelerators over very short distances, and about one order of magnitude better at the one meter scale.
The AWAKE facility at CERN is a proof-of-principle experiment, which investigates wakefield plasma acceleration using a proton bunch as a driver, a world-wide first. It aims to accelerate a low-energy witness bunch of electrons from 15 to 20 MeV to several GeV over a short distance by creating a high acceleration gradient of several GV/m. Particle accelerators currently in use, like CERN's LHC, use standard or superconductive RF-cavities for acceleration, but they are limited to an acceleration gradient in the order of 100 MV/m.
Electron beam ion trap (EBIT) is an electromagnetic bottle that produces and confines highly charged ions. An EBIT uses an electron beam focused with a powerful magnetic field to ionize atoms to high charge states by successive electron impact.
Atomtronics is an emerging type of computing consisting of matter-wave circuits which coherently guide propagating ultra-cold atoms. The systems typically include components analogous to those found in electronic or optical systems, such as beam splitters and transistors. Applications range from studies of fundamental physics to the development of practical devices.
The Breit–Wheeler process or Breit–Wheeler pair production is a proposed physical process in which a positron–electron pair is created from the collision of two photons. It is the simplest mechanism by which pure light can be potentially transformed into matter. The process can take the form γ γ′ → e+ e− where γ and γ′ are two light quanta.
Chandrashekhar "Chan" Janardan Joshi is an Indian-American experimental plasma physicist. He is known for his pioneering work in plasma-based particle acceleration techniques for which he won the 2006 James Clerk Maxwell Prize for Plasma Physics.
The NA63 experiment aims to study the radiation process in strong electromagnetic fields. Located at CERN, in the North Area. It is a fixed-target experiment which uses the H4 secondary electron beams from the SPS, which are directed onto different targets. Those are made from a variety of elements, ranging from the relatively light carbon and silicon, through the heavier iron and tin to tungsten, gold and lead and are either amorphous or mono-crystals.
Jochen Küpper FRSC is a German chemist and physicist, group leader at the Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, and Professor of Physics and Professor by courtesy of Chemistry at the University of Hamburg, Germany.
Louis Franklin DiMauro is an American atomic physicist, the Edward and Sylvia Hagenlocker Professor In the Department of Physics at The Ohio State University, Columbus, Ohio, USA. His interests are atomic, molecular and optical physics. He has been elected a Fellow of the American Association for the Advancement of Science, American Physical Society and Optical Society.
Bose–Einstein condensation of polaritons is a growing field in semiconductor optics research, which exhibits spontaneous coherence similar to a laser, but through a different mechanism. A continuous transition from polariton condensation to lasing can be made similar to that of the crossover from a Bose–Einstein condensate to a BCS state in the context of Fermi gases. Polariton condensation is sometimes called “lasing without inversion”.
In accelerator physics, a kinematically complete experiment is an experiment in which all kinematic parameters of all collision products are determined. If the final state of the collision involves n particles 3n momentum components need to be determined. However, these components are linked to each other by momentum conservation in each direction and energy conservation so that only 3n-4 components are linearly independent. Therefore, the measurement of 3n-4 momentum components constitutes a kinematically complete experiment.
Guy Laval is a French physicist, professor at the École polytechnique and member of the French Academy of Sciences.
Jürgen Meyer-ter-Vehn is a German theoretical physicist who specializes in laser-plasma interactions at the Max Planck Institute for Quantum Optics. He published under the name Meyer until 1973.
The Penning–Malmberg trap, named after Frans Penning and John Malmberg, is an electromagnetic device used to confine large numbers of charged particles of a single sign of charge. Much interest in Penning–Malmberg (PM) traps arises from the fact that if the density of particles is large and the temperature is low, the gas will become a single-component plasma. While confinement of electrically neutral plasmas is generally difficult, single-species plasmas can be confined for long times in PM traps. They are the method of choice to study a variety of plasma phenomena. They are also widely used to confine antiparticles such as positrons and antiprotons for use in studies of the properties of antimatter and interactions of antiparticles with matter.
The Lawson–Woodward theorem is a physics theorem about particle acceleration with electromagnetic wave. This theorem roughly states that an electromagnetic plane wave can not provide a net acceleration to an ultra-relativistic charged particle in vacuum. This is a theoretical limitation to particle acceleration, especially for laser-based electron accelerator. Any laser-based particle accelerator should then break at least one of the hypotheses of the Lawson–Woodward theorem to be physically possible
Patrick Mora is a French theoretical plasma physicist who specializes in laser-plasma interactions. He was awarded the 2014 Hannes Alfvén Prize and 2019 Edward Teller Award for his contributions to the field of laser-plasma physics.
Toshiki Tajima is a Japanese theoretical plasma physicist known for pioneering the laser wakefield acceleration technique with John M. Dawson in 1979. The technique is used to accelerate particles in a plasma and was experimentally realized in 1994, for which Tajima received several awards such as the Nishina Memorial Prize (2006), the Enrico Fermi Prize (2015), the Robert R. Wilson Prize (2019), the Hannes Alfvén Prize (2019) and the Charles Hard Townes Award (2020).
Sergei Vladimirovich Bulanov, is a Russian physicist. He received the 1983 State Prize of the USSR, the 2016 Hannes Alfvén Prize for "contributions to the development of large-scale next-step devices in high-temperature plasma physics research", and the Order of Rising Sun with Gold Rays and Rosette in 2020.
Warren Bicknell Mori is an American computational plasma physicist and a professor at the University of California, Los Angeles. He was awarded the 2020 James Clerk Maxwell Prize for Plasma Physics for his contributions to the theory and computer simulations of non-linear processes in plasma-based acceleration using kinetic theory, as well as for his research in relativistically intense lasers and beam-plasma interactions.
