Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Energy Diffusion in Gases   In the air surrounding us, how does a particle diffuse? Thanks to Einstein
and other pioneers,it has been well known that generally the particle will
undergo the Brownian motion, and in the last century this insight has been
corroborated by numerous experiments and applications. Another fundamental
question is how the energy carried by a particle diffuses. The conventional
transport theories assumed the Brownian motion as the underlying energy
transporting mechanism, but however, it should be noticed that in fact this
assumption has never been tested and verified directly in experiments. Here we
show that in clear contrast to the prediction based on the Brownian motion, in
equilibrium gases the energy diffuses ballistically instead, spreading in a way
analogous to a tsunami wave. This finding suggests a conceptually new
perspective for revisiting the existing energy transport theories of gases, and
provides a chance to solve some important application problems having
challenged these theories for decades.

18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
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The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
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The categories of this paper are: stat
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol