Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Non-Archimedean character of quantum buoyancy and the generalized second
  law of thermodynamics   Quantum buoyancy has been proposed as the mechanism protecting the
generalized second law when an entropy--bearing object is slowly lowered
towards a black hole and then dropped in. We point out that the original
derivation of the buoyant force from a fluid picture of the acceleration
radiation is invalid unless the object is almost at the horizon, because
otherwise typical wavelengths in the radiation are larger than the object. The
buoyant force is here calculated from the diffractive scattering of waves off
the object, and found to be weaker than in the original theory. As a
consequence, the argument justifying the generalized second law from buoyancy
cannot be completed unless the optimal drop point is next to the horizon. The
universal bound on entropy is always a sufficient condition for operation of
the generalized second law, and can be derived from that law when the optimal
drop point is close to the horizon. We also compute the quantum buoyancy of an
elementary charged particle; it turns out to be negligible for energetic
considerations. Finally, we speculate on the significance of the absence from
the bound of any mention of the number of particle species in nature.

9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin