Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Protecting a diamond quantum memory by charge state control   In recent years, solid-state spin systems have emerged as promising
candidates for quantum information processing (QIP). Prominent examples are the
Nitrogen-Vacancy (NV) center in diamond, phosphorous dopants in silicon (Si:P),
rare-earth ions in solids and V$_{\text{Si}}$-centers in Silicon-carbide (SiC).
The Si:P system has demonstrated, that by eliminating the electron spin of the
dopant, its nuclear spins can yield exceedingly long spin coherence times. For
NV centers, however, a proper charge state for storage of nuclear spin qubit
coherence has not been identified yet. Here, we identify and characterize the
positively charged NV center as an electron-spin-less and optically inactive
state by utilizing the nuclear spin qubit as a probe. We control the electronic
charge and spin utilizing nanometer scale gate electrodes. We achieve a
lengthening of the nuclear spin coherence times by a factor of 20.
Surprisingly, the new charge state allows switching the optical response of
single nodes facilitating full individual addressability.

32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs