Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ensemble spin relaxation of shallow donor qubits in ZnO   We present an experimental and theoretical study of the longitudinal electron
spin relaxation ($T_1$) of shallow donors in the direct band-gap semiconductor
ZnO. $T_1$ is measured via resonant excitation of the Ga donor-bound exciton.
$T_1$ exhibits an inverse-power dependence on magnetic field $T_1\propto
B^{-n}$, with $4\leq n\leq 5$, over a field range of 1.75 T to 7 T. We derive
an analytic expression for the donor spin-relaxation rate due to spin-orbit
(admixture mechanism) and electron-phonon (piezoelectric) coupling for the
wurtzite crystal symmetry. Excellent quantitative agreement is found between
experiment and theory suggesting the admixture spin-orbit mechanism is the
dominant contribution to $T_1$ in the measured magnetic field range.
Temperature and excitation-energy dependent measurements indicate a donor
density dependent interaction may contribute to small deviations between
experiment and theory. The longest $T_1$ measured is 480 ms at 1.75 T with
increasing $T_1$ at smaller fields theoretically expected. This work highlights
the extremely long longitudinal spin-relaxation time for ZnO donors due to
their small spin-orbit coupling.

15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
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The categories of this paper are: eess
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci