5,389 research outputs found
Universality of returning electron wave packet in high-order harmonic generation with midinfrared laser pulses
We show that a returning electron wave packet in high-order harmonic generation (HHG) with midinfrared laser pulses converges to a universal limit for a laser wavelength above about 3 μm. The results are consistent among the different methods: a numerical solution of the time-dependent Schrödinger equation, the strong-field approximation, and the quantum orbits theory. We further analyze how the contribution from different electron “trajectories” survives the macroscopic propagation in the medium. Our result thus provides a new framework for investigating the wavelength scaling law for the HHG yields
Experimental Trapped-ion Quantum Simulation of the Kibble-Zurek dynamics in momentum space
The Kibble-Zurek mechanism is the paradigm to account for the nonadiabatic
dynamics of a system across a continuous phase transition. Its study in the
quantum regime is hindered by the requisite of ground state cooling. We report
the experimental quantum simulation of critical dynamics in the
transverse-field Ising model by a set of Landau-Zener crossings in
pseudo-momentum space, that can be probed with high accuracy using a single
trapped ion. We test the Kibble-Zurek mechanism in the quantum regime in the
momentum space and find the measured scaling of excitations is in accordance
with the theoretical prediction.Comment: 10 pages, 3 figures Published in Scientific Reports,
http://www.nature.com/articles/srep3338
Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's Space Station
HERD is the High Energy cosmic-Radiation Detection instrument proposed to
operate onboard China's space station in the 2020s. It is designed to detect
energetic cosmic ray nuclei, leptons and photons with a high energy resolution
( for electrons and photons and for nuclei) and a large
geometry factor ( for electrons and diffuse photons and for nuclei). In this work we discuss the capability of HERD to detect
monochromatic -ray lines, based on simulations of the detector
performance. It is shown that HERD will be one of the most sensitive
instruments for monochromatic -ray searches at energies between
to a few hundred GeV. Above hundreds of GeV, Cherenkov telescopes will
be more sensitive due to their large effective area. As a specific example, we
show that a good portion of the parameter space of a supersymmetric dark matter
model can be probed with HERD.Comment: 9 pages, 7 figures, matches version published in Astropart.Phy
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