Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Metal-insulator transition in YHx: scaling of the sub-THz conductivity   The established scaling laws of the conductivity with temperature and doping
are strong indications for the quantum nature of the metal-insulator transition
in YH$_x$. Here we report the first results on the frequency scaling of the
conductivity. Samples were brought from the insulating to the metallic phase by
carrier doping via illumination. In the metallic phase, the sub-terahertz
conductivity coincides with the dc data. These results do not agree with the
simplest picture of a quantum-phase transition.

31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph