Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Canceling the cavity length induced phase noise in an optical ring
  cavity for phase shift measurement and spin squeezing   We demonstrate a new method of light phase shift measurement using a
high-finesse optical ring cavity which exhibits reduced phase noise due to
cavity length fluctuations. Two laser beams with a frequency difference of one
cavity free spectral range are simultaneously resonant with the cavity,
demonstrating noise correlations in the error signals due to the common-mode
cavity length fluctuations. The differential error signal shows a 30 dB
reduction in cavity noise down to the noise floor in a frequency range up to
half the cavity linewidth ($\delta\nu/2 \simeq 30$ kHz). Various noise sources
are analyzed and their contributions to the noise floor are evaluated.
Additionally, we apply this noise-reduced phase shift measurement scheme in a
simulated spin-squeezing experiment where we have achieved a factor of 40
improvement in phase sensitivity with a phase resolution of 0.7 mrad, which may
remove one important barrier against attaining highly spin-squeezed states. The
demonstrated method is the first reported measurement using an optical ring
cavity and two independent beams, a flexible situation. This method can find
direct application to non-destructive measurements in quantum systems, such as
for the generation of spin-squeezed states in atom interferometers and atomic
clocks.

22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc