13,312 research outputs found
Electromagnetic and gravitational radiation from the coherent oscillation of electron-positron pairs and fields
Integrating equations of particle-number and energy-momentum conservation and
Maxwell field equations, we study the oscillation and drift of electron and
positron pairs coherently with fields after these pairs are produced in
external electromagnetic fields. From the electric current of oscillating
pairs, we obtain the energy spectrum of electromagnetic dipole radiation. This
narrow spectrum is so peculiar that the detection of such radiation can
identify pair production and oscillation in strong laser fields. We also obtain
the energy spectrum of gravitational quadrapole radiation from the
energy-momentum tensor of oscillating pairs and fields. Thus, we discuss the
generation of gravitational waves on the basis of rapid development of strong
laser fields.Comment: 6 pages, 4 figure
On Gaussian Comparison Inequality and Its Application to Spectral Analysis of Large Random Matrices
Recently, Chernozhukov, Chetverikov, and Kato [Ann. Statist. 42 (2014)
1564--1597] developed a new Gaussian comparison inequality for approximating
the suprema of empirical processes. This paper exploits this technique to
devise sharp inference on spectra of large random matrices. In particular, we
show that two long-standing problems in random matrix theory can be solved: (i)
simple bootstrap inference on sample eigenvalues when true eigenvalues are
tied; (ii) conducting two-sample Roy's covariance test in high dimensions. To
establish the asymptotic results, a generalized -net argument
regarding the matrix rescaled spectral norm and several new empirical process
bounds are developed and of independent interest.Comment: to appear in Bernoull
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