Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Broadband Measurement of Coating Thermal Noise in Rigid Fabry-Perot
  Cavities   We report on the relative length fluctuation of two fixed-spacer Fabry-Perot
cavities with mirrors fabricated from silica/tantala dielectric coatings on
fused silica substrates. By locking a laser to each cavity and reading out the
beat note $\hat{\nu} = \nu_1 - \nu_2$ of the transmitted beams, we find that,
for frequencies from 10 Hz to 1 kHz, the amplitude spectral density of beat
note fluctuation is $\sqrt{S_\hat{\nu}(f)} = (0.5\,\mathrm{Hz})/f^{1/2}$. By
careful budgeting of noise sources contributing to the beat note, we find that
our measurement is consistent with the fluctuation in this band being dominated
by the Brownian noise of the mirror coatings. Fitting for the coating loss
angle $\phi_\mathrm{c}$, we find it equal to $4\times10^{-4}$. We then use a
Bayesian analysis to combine our measurement with previous observations, and
thereby extract estimates for the individual loss angles of silica and tantala.
It is hoped that the testbed described in this article can be used in the
future to measure the length noise of cavities formed with novel mirror
materials and geometries.

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The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
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The categories of this paper are: eess
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: adap-org