Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generalized Second Law for Cosmology   We conjecture a novel Generalized Second Law that can be applied in
cosmology, regardless of whether an event horizon is present: the generalized
entropy increases monotonically outside of certain hypersurfaces we call past
Q-screens. A past Q-screen is foliated by surfaces whose generalized entropy
(sum of area and entanglement entropy) is stationary along one future null
direction and increasing along the other. We prove that our Generalized Second
Law holds in spacetimes obeying the Quantum Focussing Conjecture. An analogous
law applies to future Q-screens, which appear inside evaporating black holes
and in collapsing regions.

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The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom