2,191 research outputs found
The squeezed light source for the advanced virgo detector in the observation run O3
From 1 April 2019 to 27 March 2020, the Advanced Virgo detector, together with the two Advanced LIGO detectors, conducted the third joint scientific observation run O3, aiming for further detections of gravitational wave signals from astrophysical sources. One of the upgrades to the Virgo detector for O3 was the implementation of the squeezed light technology to improve the detector sensitivity beyond its classical quantum shot noise limit. In this paper, we present a detailed description of the optical setup and performance of the employed squeezed light source. The squeezer was constructed as an independent, stand-alone sub-system operated in air. The generated squeezed states are tailored to exhibit high purity at intermediate squeezing levels in order to significantly reduce the interferometer shot noise level while keeping the correlated enhancement of quantum radiation pressure noise just below the actual remaining technical noise in the Advanced Virgo detector
Complex floral behavior of an angiosperm family
Segundo-Ortin & Calvo provide a comprehensive overview of the many aspects of plant behavior examined to date. In our view, multiple lines of evidence make it difficult to deny plant sentience. We add further evidence to support the conclusion that plants are sentient organisms. As in animals, the behavior of plants can be seen and studied as an evolutionary trait, subject to and a consequence of increasing complexity in the interactions of plants with their environment. Our example is the evolution of floral behavior in Loasaceae, where complex patterns of stamen movement have co-evolved in interaction with specialized pollinators
Bose-Fermi Mixtures in a Three-dimensional Optical Lattice
We have studied mixtures of fermionic K and bosonic Rb quantum
gases in a three-dimensional optical lattice. We observe that an increasing
admixture of the fermionic species diminishes the phase coherence of the
bosonic atoms as measured by studying both the visibility of the matter wave
interference pattern and the coherence length of the bosons. Moreover, we find
that the attractive interactions between bosons and fermions lead to an
increase of the boson density in the lattice which we measure by studying
three-body recombination in the lattice. In our data we do not observe
three-body loss of the fermionic atoms. An analysis of the thermodynamics of a
noninteracting Bose-Fermi mixture in the lattice suggests a mechanism for
sympathetic cooling of the fermions in the lattice
Molecules of Fermionic Atoms in an Optical Lattice
We create molecules from fermionic atoms in a three-dimensional optical
lattice using a Feshbach resonance. In the limit of low tunnelling, the
individual wells can be regarded as independent three-dimensional harmonic
oscillators. The measured binding energies for varying scattering length agree
excellently with the theoretical prediction for two interacting atoms in a
harmonic oscillator. We demonstrate that the formation of molecules can be used
to measure the occupancy of the lattice and perform thermometry.Comment: 4 page
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