Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Millisecond Electron-Phonon Relaxation in Ultrathin Disordered Metal
  Films at Millikelvin Temperatures   We have measured directly the thermal conductance between electrons and
phonons in ultra-thin Hf and Ti films at millikelvin temperatures. The
experimental data indicate that electron-phonon coupling in these films is
significantly suppressed by disorder. The electron cooling time $\tau_\epsilon$
follows the $T^{-4}$-dependence with a record-long value $\tau_\epsilon=25ms$
at $T=0.04K$. The hot-electron detectors of far-infrared radiation, fabricated
from such films, are expected to have a very high sensitivity. The noise
equivalent power of a detector with the area $1\mum^2$ would be
$(2-3)10^{-20}W/Hz^{1/2}$, which is two orders of magnitude smaller than that
of the state-of-the-art bolometers.

20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
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The categories of this paper are: eess
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
2
The categories of this paper are: math