41,951 research outputs found

    The Low Energy Limit of the Chern-Simons Theory Coupled to Fermions

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    We study the nonrelativistic limit of the theory of a quantum Chern--Simons field minimally coupled to Dirac fermions. To get the nonrelativistic effective Lagrangian one has to incorporate vacuum polarization and anomalous magnetic moment effects. Besides that, an unsuspected quartic fermionic interaction may also be induced. As a by product, the method we use to calculate loop diagrams, separating low and high loop momenta contributions, allows to identify how a quantum nonrelativistic theory nests in a relativistic one.Comment: 18 pages, 8 figures, Late

    Ion motion in the wake driven by long particle bunches in plasmas

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    We explore the role of the background plasma ion motion in self-modulated plasma wakefield accelerators. We employ J. Dawson's plasma sheet model to derive expressions for the transverse plasma electric field and ponderomotive force in the narrow bunch limit. We use these results to determine the on-set of the ion dynamics, and demonstrate that the ion motion could occur in self-modulated plasma wakefield accelerators. Simulations show the motion of the plasma ions can lead to the early suppression of the self-modulation instability and of the accelerating fields. The background plasma ion motion can nevertheless be fully mitigated by using plasmas with heavier plasmas.Comment: 23 pages, 6 figure

    Controlled Shock Shells and Intracluster Fusion Reactions in the Explosion of Large Clusters

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    The ion phase-space dynamics in the Coulomb explosion of very large (∼106−107\sim 10^6 - 10^7 atoms) deuterium clusters can be tailored using two consecutive laser pulses with different intensities and an appropriate time delay. For suitable sets of laser parameters (intensities and delay), large-scale shock shells form during the explosion, thus highly increasing the probability of fusion reactions within the single exploding clusters. In order to analyze the ion dynamics and evaluate the intracluster reaction rate, a one-dimensional theory is used, which approximately accounts for the electron expulsion from the clusters. It is found that, for very large clusters (initial radius ∼\sim 100 nm), and optimal laser parameters, the intracluster fusion yield becomes comparable to the intercluster fusion yield. The validity of the results is confirmed with three-dimensional particle-in-cell simulations.Comment: 25 pages, 11 figures, to appear in Physical Review

    On the finiteness of the noncommutative supersymmetric Maxwell-Chern-Simons theory

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    Within the superfield approach, we prove the absence of UV/IR mixing in the three-dimensional noncommutative supersymmetric Maxwell-Chern-Simons theory at any loop order and demonstrate its finiteness in one, three and higher loop orders.Comment: 9 pages, 2 figures, revtex

    Wigner-Moyal description of free variable mass Klein-Gordon fields

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    A system of coupled kinetic transport equations for the Wigner distributions of a free variable mass Klein-Gordon field is derived. This set of equations is formally equivalent to the full wave equation for electromagnetic waves in nonlinear dispersive media, thus allowing for the description of broadband radiation-matter interactions and the associated instabilities. The standard results for the classical wave action are recovered in the short wavelength limit of the generalized Wigner-Moyal formalism for the wave equation.Comment: 9 pages, accepted for publication in Journal of Mathematical Physic

    All-optical trapping and acceleration of heavy particles

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    A scheme for fast, compact, and controllable acceleration of heavy particles in vacuum is proposed, in which two counterpropagating lasers with variable frequencies drive a beat-wave structure with variable phase velocity, thus allowing for trapping and acceleration of heavy particles, such as ions or muons. Fine control over the energy distribution and the total charge of the beam is obtained via tuning of the frequency variation. The acceleration scheme is described with a one-dimensional theory, providing the general conditions for trapping and scaling laws for the relevant features of the particle beam. Two-dimensional, electromagnetic particle-in-cell simulations confirm the validity and the robustness of the physical mechanism.Comment: 10 pages, 3 figures, to appear in New Journal of Physic

    Three-dimensional simulations of laser-plasma interactions at ultrahigh intensities

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    Three-dimensional (3D) particle-in-cell (PIC) simulations are used to investigate the interaction of ultrahigh intensity lasers (>1020> 10^{20} W/cm−2^{-2}) with matter at overcritical densities. Intense laser pulses are shown to penetrate up to relativistic critical density levels and to be strongly self-focused during this process. The heat flux of the accelerated electrons is observed to have an annular structure when the laser is tightly focused, showing that a large fraction of fast electrons is accelerated at an angle. These results shed light into the multi-dimensional effects present in laser-plasma interactions of relevance to fast ignition of fusion targets and laser-driven ion acceleration in plasmas.Comment: 2 pages, 1 figur
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