Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Boltzmann Transport in Nanostructures as a Friction Effect   Surface scattering is the key limiting factor to thermal transport in
dielectric crystals as the length scales are reduced or when temperature is
lowered. To explain this phenomenon, it is commonly assumed that the mean free
paths of heat carriers are bound by the crystal size and that thermal
conductivity is reduced in a manner proportional to such mean free paths. We
show here that these conclusions rely on simplifying assumptions and
approximated transport models. Instead, starting from the linearized Boltzmann
transport equation in the relaxon basis, we show how the problem can be reduced
to a set of decoupled linear differential equations. Then, the heat flow can be
interpreted as a hydrodynamic phenomenon, with the relaxon gas being slowed
down in proximity of a surface by friction effects, similar to the flux of a
viscous fluid in a pipe. As an example, we study a ribbon and a trench of
monolayer molybdenum disulphide, describing the procedure to reconstruct the
temperature and thermal conductivity profile in the sample interior and showing
how to estimate the effect of nanostructuring. The approach is general and
could be extended to other transport carriers, such as electrons, or extended
to materials of higher dimensionality and to different geometries, such as thin
films.

14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an