Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Prototype of a Compact Rubidium-Based Optical Frequency Reference for
  Operation on Nanosatellites   Space-borne optical frequency references based on spectroscopy of atomic
vapors may serve as an integral part of compact optical atomic clocks, which
can advance global navigation systems, or can be utilized for earth observation
missions as part of laser systems for cold atom gradiometers. Nanosatellites
offer low launch-costs, multiple deployment opportunities and short payload
development cycles, enabling rapid maturation of optical frequency references
and underlying key technologies in space. Towards an in-orbit demonstration on
such a platform, we have developed a CubeSat-compatible prototype of an optical
frequency reference based on the D2-transition in rubidium. A frequency
instability of 1.7e-12 at 1 s averaging time is achieved. The optical module
occupies a volume of 35 cm^3, weighs 73 g and consumes 780 mW of power.

17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th