Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heavy electrons: Electron droplets generated by photogalvanic and
  pyroelectric effects   Electron clusters, X-rays and nanosecond radio-frequency pulses are produced
by 100 mW continuous-wave laser illuminating ferroelectric crystal of LiNbO_3.
A long-living stable electron droplet with the size of about 100 mcm has freely
moved with the velocity 0.5 cm/s in the air near the surface of the crystal
experiencing the Earth gravitational field. The microscopic model of cluster
stability, which is based on submicroscopic mechanics developed in the real
physical space, is suggested. The role of a restraining force plays the inerton
field, a substructure of the particles' matter waves, which a solitary one can
elastically withstand the Coulomb repulsion of electrons. It is shown that
electrons in the droplet are heavy electrons whose mass at least 1 million of
times exceeds the rest mass of free electron. Application for X-ray imaging and
lithography is discussed.

26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci