77 research outputs found
Relativistic diffusion with friction on a pseudoriemannian manifold
We study a relativistic diffusion equation on the Riemannian phase space
defined by Franchi and Le Jan. We discuss stochastic Ito (Langevin)
differential equations (defining the diffusion) as a perturbation by noise of
the geodesic equation. We show that the expectation value of the angular
momentum and the energy grow exponentially fast. We discuss drifts leading to
an equilibrium. It is shown that the diffusion process corresponding to the
Juettner or quantum equilibrium distributions has a bounded expectation value
of angular momentum and energy. The energy and the angular momentum tend
exponentially fast to their equilibrium values. As examples we discuss a
particle in a plane fronted gravitational wave and a particle in de Sitter
universe. It is shown that the relativistic diffusion of momentum in de Sitter
space is the same as the relativistic diffusion on the Minkowski mass-shell
with the temperature proportional to the de Sitter radius.Comment: the version published in CQ
Relativistic diffusion of elementary particles with spin
We obtain a generalization of the relativistic diffusion of Schay and Dudley
for particles with spin. The diffusion equation is a classical version of an
equation for the Wigner function of an elementary particle. The elementary
particle is described by a unitary irreducible representation of the Poincare
group realized in the Hilbert space of wave functions in the momentum space.
The arbitrariness of the Wigner rotation appears as a gauge freedom of the
diffusion equation. The spin is described as a connection of a fiber bundle
over the momentum hyperbolic space (the mass-shell). Motion in an
electromagnetic field, transport equations and equilibrium states are
discussed.Comment: 21 pages,minor changes,the version published in Journ.Phys.
Species active in the selective catalytic reduction of no with iso-butane on iron-exchanged ZSM-5 zeolites
Transient Studies of Oxygen Removal Pathways and Catalytic Redox Cycles during NO Decomposition on Cu−ZSM5
High-field high-repetition-rate sources for the coherent THz control of matter
Ultrashort flashes of THz light with low photon energies of a few meV, but strong electric or magnetic field transients have recently been employed to prepare various fascinating nonequilibrium states in matter. Here we present a new class of sources based on superradiant enhancement of radiation from relativistic electron bunches in a compact electron accelerator that we believe will revolutionize experiments in this field. Our prototype source generates high-field THz pulses at unprecedented quasicontinuous-wave repetition rates up to the MHz regime. We demonstrate parameters that exceed state-of-the-art laser-based sources by more than 2 orders of magnitude. The peak fields and the repetition rates are highly scalable and once fully operational this type of sources will routinely provide 1 MV/cm electric fields and 0.3 T magnetic fields at repetition rates of few 100 kHz. We benchmark the unique properties by performing a resonant coherent THz control experiment with few 10 fs resolution
Pseudouridylation defect due to DKC1 and NOP10 mutations causes nephrotic syndrome with cataracts, hearing impairment, and enterocolitis
Research UK Innovation and Project; Cancer Research U
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