Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A low phase noise microwave source for atomic spin squeezing experiments
  in 87Rb   We describe and characterize a simple, low cost, low phase noise microwave
source that operates near 6.800 GHz for agile, coherent manipulation of
ensembles of 87Rb. Low phase noise is achieved by directly multiplying a low
phase noise 100 MHz crystal to 6.8 GHz using a non-linear transmission line and
filtering the output with custom band-pass filters. The fixed frequency signal
is single sideband modulated with a direct digital synthesis frequency source
to provide the desired phase, amplitude, and frequency control. Before
modulation, the source has a single sideband phase noise near -140 dBc/Hz in
the range of 10 kHz to 1 MHz offset from the carrier frequency and -130 dBc/Hz
after modulation. The resulting source is estimated to contribute added
spin-noise variance 16 dB below the quantum projection noise level during
quantum nondemolition measurements of the clock transition in an ensemble
7x10^5 87Rb atoms.

14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th