Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Van Hove's "\lambda^2 t" limit in nonrelativistic and relativistic
  field-theoretical models   Van Hove's "\lambda^2 t" limiting procedure is analyzed in some interesting
quantum field theoretical cases, both in nonrelativistic and relativistic
models. We look at the deviations from a purely exponential behavior in a decay
process and discuss the subtle issues of state preparation and initial time.

8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an