Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum Cherenkov radiation by spinless and spin-1/2 particles   In this paper, the Cherenkov radiation process is investigated in the frame
of the Quantum Field Theory, both for the spinless and spin-1/2 charged
particles. In the latter case, the polarization density matrix technique was
used to account for the spin flip. If compared with the Classical
Electrodynamics results, in both cases several quantum corrections arise,
coinciding up to the photon's energy linear term. It is shown that, while the
absolute value of these corrections significantly relies on the refractive
index, the relative quantum correction stays independent of the medium in the
case of the ultrarelativistic particles. It the case of the spin-1/2 particles
it turns out that the spin flip practically never occurs in this process. For
both cases, spinless and spin-1/2, the outgoing photon polarization vector lies
always in the plane formed by the initial particle's momentum vector and the
final photon's wave vector.

2
The categories of this paper are: math
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph