Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultra-sensitive Diamond Magnetometry Using Optimal Dynamic Decoupling   New magnetometry techniques based on Nitrogen Vacancy (NV) defects in diamond
have received much attention of late as a means to probe nanoscale magnetic
environments. The sensitivity of a single NV magnetometer is primarily
determined by the transverse spin relaxation time, $T_2$. Current approaches to
improving the sensitivity employ crystals with a high NV density at the cost of
spatial resolution, or extend $T_2$ via the manufacture of novel isotopically
pure diamond crystals. We adopt a complementary approach, in which optimal
dynamic decoupling techniques extend coherence times out to the
self-correlation time of the spin bath. This suggests single spin, room
temperature magnetometer sensitivities as low as 5\,pT\,Hz$^{-1/2}$ with
current technology.

9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex