6 research outputs found
Quantum-Assisted Telescope Arrays
Quantum networks provide a platform for astronomical interferometers capable
of imaging faint stellar objects. In a recent work [arXiv:1809.01659], we
presented a protocol that circumvents transmission losses with efficient use of
quantum resources and modest quantum memories. Here we analyze a number of
extensions to that scheme. We show that it can be operated as a truly broadband
interferometer and generalized to multiple sites in the array. We also analyze
how imaging based on the quantum Fourier transform provides improved
signal-to-noise ratio compared to classical processing. Finally, we discuss
physical realizations including photon-detection-based quantum state transfer.Comment: 10 pages, 8 figures; v2 - clarifications and references; v3 - close
to published versio
Three-dimensional single gyroid photonic crystals with a mid-infrared bandgap
A gyroid structure is a distinct morphology that is triply periodic and
consists of minimal isosurfaces containing no straight lines. We have designed
and synthesized amorphous silicon (a-Si) mid-infrared gyroid photonic crystals
that exhibit a complete bandgap in infrared spectroscopy measurements. Photonic
crystals were synthesized by deposition of a-Si/Al2O3 coatings onto a
sacrificial polymer scaffold defined by two-photon lithography. We observed a
100% reflectance at 7.5 \mum for single gyroids with a unit cell size of 4.5
\mum, in agreement with the photonic bandgap position predicted from full-wave
electromagnetic simulations, whereas the observed reflection peak shifted to 8
um for a 5.5 \mum unit cell size. This approach represents a
simulation-fabrication-characterization platform to realize three-dimensional
gyroid photonic crystals with well-defined dimensions in real space and
tailored properties in momentum space
Optical Interferometry with Quantum Networks
We propose a method for optical interferometry in telescope arrays assisted
by quantum networks. In our approach, the quantum state of incoming photons
along with an arrival time index is stored in a binary qubit code at each
receiver. Nonlocal retrieval of the quantum state via entanglement-assisted
parity checks at the expected photon arrival rate allows for direct extraction
of the phase difference, effectively circumventing transmission losses between
nodes. Compared to prior proposals, our scheme (based on efficient quantum data
compression) offers an exponential decrease in required entanglement bandwidth.
Experimental implementation is then feasible with near-term technology,
enabling optical imaging of astronomical objects akin to well-established radio
interferometers and pushing resolution beyond what is practically achievable
classically.Comment: 7 + 6 pages, 3 + 1 figures; v2 - clarifications and further
discussion of implementation; v3 - close to published versio
Changing Ionization Conditions in SDSS Galaxies with AGN as a Function of Environment from Pairs to Clusters
We study how AGN activity changes across environments from galaxy pairs to
clusters using galaxies with from the Sloan Digital Sky
Survey (SDSS). Using a refined technique, we apply a continuous measure of AGN
activity, characteristic of the ionization state of the narrow-line emitting
gas. Changes in key emission-line ratios ([NII]/H,
[OIII]/H) between different samples allow us to disentangle
different environmental effects while removing contamination. We confirm that
galaxy interactions enhance AGN activity. However, conditions in the central
regions of clusters are inhospitable for AGN activity even if galaxies are in
pairs. These results can be explained through models of gas dynamics in which
pair interactions stimulate the transfer of gas to the nucleus and clusters
suppress gas availability for accretion onto the central black hole.Comment: Accepted for publication in Ap
Changing Ionization Conditions in SDSS Galaxies with Active Galactic Nuclei as a Function of Environment from Pairs to Clusters
We study how active galactic nucleus (AGN) activity changes across environments from galaxy pairs to clusters using 143,843 galaxies with z < 0.2 from the Sloan Digital Sky Survey. Using a refined technique, we apply a continuous measure of AGN activity, characteristic of the ionization state of the narrow-line emitting gas. Changes in key emission-line ratios ([N II] λ6548/Hα, [O III] λ5007/Hβ) between different samples allow us to disentangle different environmental effects while removing contamination. We confirm that galaxy interactions enhance AGN activity. However, conditions in the central regions of clusters are inhospitable for AGN activity even if galaxies are in pairs. These results can be explained through models of gas dynamics in which pair interactions stimulate the transfer of gas to the nucleus and clusters suppress gas availability for accretion onto the central black hole