Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Addressing spin transitions on 209Bi donors in silicon using
  circularly-polarized microwaves   Over the past decade donor spin qubits in isotopically enriched $^{28}$Si
have been intensely studied due to their exceptionally long coherence times.
More recently bismuth donor electron spins have become popular because Bi has a
large nuclear spin which gives rise to clock transitions (first-order
insensitive to magnetic field noise). At every clock transition there are two
nearly degenerate transitions between four distinct states which can be used as
a pair of qubits. Here it is experimentally demonstrated that these transitions
are excited by microwaves of opposite helicity such that they can be
selectively driven by varying microwave polarization. This work uses a
combination of a superconducting coplanar waveguide (CPW) microresonator and a
dielectric resonator to flexibly generate arbitrary elliptical polarizations
while retaining the high sensitivity of the CPW.

3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
18
The categories of this paper are: econ
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess