Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electrical Detection and Magnetic-Field Control of Spin States in
  Phosphorus-Doped Silicon   Electron paramagnetic resonance of ensembles of phosphorus donors in silicon
has been detected electrically with externally applied magnetic fields lower
than 200 G. Because the spin Hamiltonian was dominated by the contact hyperfine
term rather than by the Zeeman terms at such low magnetic fields, superposition
states $ \alpha{}| \uparrow \downarrow >+\beta{}| \downarrow \uparrow >$ and
$-\beta{}| \uparrow \downarrow > + \alpha{}| \downarrow \uparrow >$ were formed
between phosphorus electron and nuclear spins, and electron paramagnetic
resonance transitions between these superposition states and $| \uparrow
\uparrow >$ or $| \downarrow \downarrow >$ states are observed clearly. A
continuous change of $\alpha{}$ and $\beta{}$ with the magnetic field was
observed with a behavior fully consistent with theory of phosphorus donors in
silicon.

28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ