Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Attosecond electron spectroscopy using a novel interferometric
  pump-probe technique   We present an interferometric pump-probe technique for the characterization
of attosecond electron wave packets (WPs) that uses a free WP as a reference to
measure a bound WP. We demonstrate our method by exciting helium atoms using an
attosecond pulse with a bandwidth centered near the ionization threshold, thus
creating both a bound and a free WP simultaneously. After a variable delay, the
bound WP is ionized by a few-cycle infrared laser precisely synchronized to the
original attosecond pulse. By measuring the delay-dependent photoelectron
spectrum we obtain an interferogram that contains both quantum beats as well as
multi-path interference. Analysis of the interferogram allows us to determine
the bound WP components with a spectral resolution much better than the inverse
of the attosecond pulse duration.

18
The categories of this paper are: econ
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess