Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermalization of small quantum systems: From the zeroth law of
  thermodynamics   Thermalization of isolated quantum systems has been studied intensively in
recent years and significant progresses have been achieved. Here, we study
thermalization of small quantum systems that interact with large chaotic
environments under the consideration of Schr\"{o}dinger evolution of composite
systems, from the perspective of the zeroth law of thermodynamics. Namely, we
consider a small quantum system that is brought into contact with a large
environmental system; after they have relaxed, they are separated and their
temperatures are studied. Our question is under what conditions the small
system may have a detectable temperature that is identical with the
environmental temperature. This should be a necessary condition for the small
quantum system to be thermalized and to have a well-defined temperature. By
using a two-level probe quantum system that plays the role of a thermometer, we
find that the zeroth law is applicable to quantum chaotic systems, but not to
integrable systems.

11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math