4,477 research outputs found
Strong field QED in lepton colliders and electron/laser interactions
Studies of strong field particle physics processes in electron/laser
interactions and lepton collider interaction points are reviewed. These
processes are defined by the high intensity of the electromagnetic fields
involved and the need to take them into account as fully as possible. The main
theoretical framework considered is the Furry picture. In this framework, the
influence of a background electromagnetic field in the Lagrangian is calculated
non perturbatively, involving exact solutions for quantised charged particles
in the background field. These "dressed" particles go on to interact
perturbatively with other particles. The background field starts to polarise
the vacuum, in effect rendering it a dispersive medium. Particles encountering
this dispersive vacuum obtain a lifetime, either radiating or decaying into
pair particles at a rate dependent on the intensity of the background field. In
fact, the intensity of the background field enters into the coupling constant
of the strong field QED Lagrangian, influencing all particle processes. A
number of new phenomena occur. Particles gain an intensity dependent rest mass
shift that accounts for their presence in the dispersive vacuum. Multi photon
events involving more than one external field photon occur at each vertex.
Higher order processes which exchange a virtual strong field particle, resonate
via the lifetimes of the unstable strong field states. Two main arenas of
strong field physics are reviewed; those occurring in relativistic electron
interactions with intense laser beams, and those occurring in the beam beam
physics at the interaction point of colliders. This review outlines the theory,
describes its significant novel phenomenology and details the experimental
schema required to detect strong field effects and the simulation programs
required to model them.Comment: Review article, 56 pages, 29 figures. Version 2 has corrected errata,
1 new reference, 5 updated figure
Introducing one-shot work into fluctuation relations
Two approaches to small-scale and quantum thermodynamics are fluctuation
relations and one-shot statistical mechanics. Fluctuation relations (such as
Crooks' Theorem and Jarzynski's Equality) relate nonequilibrium behaviors to
equilibrium quantities such as free energy. One-shot statistical mechanics
involves statements about every run of an experiment, not just about averages
over trials.
We investigate the relation between the two approaches. We show that both
approaches feature the same notions of work and the same notions of probability
distributions over possible work values. The two approaches are alternative
toolkits with which to analyze these distributions. To combine the toolkits, we
show how one-shot work quantities can be defined and bounded in contexts
governed by Crooks' Theorem. These bounds provide a new bridge from one-shot
theory to experiments originally designed for testing fluctuation theorems.Comment: 37 pages, 6 figure
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