101 research outputs found
A graphical description of optical parametric generation of squeezed states of light
No full textThe standard process for the production of strongly squeezed states of light is optical parametric amplification (OPA) below threshold in dielectric media such as LiNbO3 or periodically poled KTP. Here, we present a graphical description of squeezed light generation via OPA. It visualizes the interaction between the nonlinear dielectric polarization of the medium and the electromagnetic quantum field. We explicitly focus on the transfer from the field's ground state to a squeezed vacuum state and from a coherent state to a bright squeezed state by the medium's secondorder nonlinearity, respectively. Our pictures visualize the phase dependent amplification and deamplification of quantum uncertainties and give the phase relations between all propagating electro-magnetic fields as well as the internally induced dielectric polarizations. The graphical description can also be used to describe the generation of nonclassical states of light via higherorder effects of the non-linear dielectric polarization such as four-wave mixing and the optical Kerr effect
Strong Einstein-Podolsky-Rosen steering with unconditional entangled states
No full textIn 1935 Schrödinger introduced the terms entanglement and steering in the context of the famous gedanken experiment discussed by Einstein, Podolsky, and Rosen (EPR). Here, we report on a sixfold increase of the observed EPR-steering effect with regard to previous experiments, as quantified by the Reid criterion. We achieved an unprecedented low conditional variance product of about 0.04<1, where 1 is the upper bound below which steering is demonstrated. The steering effect was observed on an unconditional two-mode-squeezed entangled state that contained a total vacuum state contribution of less than 8%, including detection imperfections. Together with the achieved high interference contrast between the entangled state and a bright coherent laser field, our state is compatible with efficient applications in high-power laser interferometers and fiber-based networks for entanglement distribution
A gravitational wave observatory operating beyond the quantum shot-noise limit
No full textAround the globe several observatories are seeking the first direct detection of gravitational waves (GWs). These waves are predicted by Einstein’s general theory of relativity and are generated, for example, by black-hole binary systems. Present GW detectors are Michelson-type kilometre-scale laser interferometers measuring the distance changes between mirrors suspended in vacuum. The sensitivity of these detectors at frequencies above several hundred hertz is limited by the vacuum (zero-point) fluctuations of the electromagnetic field. A quantum technology—the injection of squeezed light—offers a solution to this problem. Here we demonstrate the squeezed-light enhancement of GEO600, which will be the GWobservatory operated by the LIGO Scientific Collaboration in its search for GWs for the next 3–4 years. GEO600 now operates with its best ever sensitivity, which proves the usefulness of quantum entanglement and the qualification of squeezed light as a key technology for future GW astronomy.J. Abadie... M.R. Ganija... D.J. Hosken... J. Munch... D.J. Ottaway... P.J. Veitch... et al. J. Abadie... M. R. Ganija...D. J. Hosken... J. Munch... D. J. Ottaway... P. J. Veitch... et al., (LIGO Scientific Collaboration
Quantum-dense metrology
No full textQuantum metrology utilizes entanglement for improving the sensitivity ofmeasurements. Up to now the focus has been on the measurement of just one outof two non-commuting observables. Here we demonstrate a laser interferometerthat provides information about two non-commuting observables, withuncertainties below that of the meter's quantum ground state. Our experiment isa proof-of-principle of quantum dense metrology, and uses the additionalinformation to distinguish between the actual phase signal and a parasiticsignal due to scattered and frequency shifted photons. Our approach can bereadily applied to improve squeezed-light enhanced gravitational-wave detectorsat non-quantum noise limited detection frequencies in terms of a sub shot-noiseveto-channel.<br
Verbreiterung und Umbau der Rheinbrücke Köln-Rodenkirchen - Ausführung der Verbreiterung
No full textEnhanced sensitivity of the LIGO gravitational wave detector by using squeezed states of light
No full textLIGO Scientific Collaboration members: J. Munch, D. J. Ottaway, P. J. Veitch for University of Adelaide.Nearly a century after Einstein first predicted the existence of gravitational waves, a global network of Earth-based gravitational wave observatories¹,²,³,⁴ is seeking to directly detect this faint radiation using precision laser interferometry. Photon shot noise, due to the quantum nature of light, imposes a fundamental limit on the attometre-level sensitivity of the kilometre-scale Michelson interferometers deployed for this task. Here, we inject squeezed states to improve the performance of one of the detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) beyond the quantum noise limit, most notably in the frequency region down to 150 Hz, critically important for several astrophysical sources, with no deterioration of performance observed at any frequency. With the injection of squeezed states, this LIGO detector demonstrated the best broadband sensitivity to gravitational waves ever achieved, with important implications for observing the gravitational-wave Universe with unprecedented sensitivity.The LIGO Scientific Collaboratio
Verbreiterung und Umbau der Rheinbrücke Köln-Rodenkirchen - Umbau der vorhandenen Brücke
No full textErratum: Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1 (Physical Review D - Particles, Fields, Gravitation and Cosmology)
No full textThis paper was published online on 5 November 2010 with an omission in the Collaboration author list. S. Dwyer has
been added as of 12 April 2012. The Collaboration author list is incorrect in the printed version of the journal
Implications for the origin Of GRB 051103 from LIGO observations
No full textWe present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a shortduration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6 Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at a distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB 051103. Assuming weakly beamed γ -ray emission with a jet semi-angle of 30◦, we exclude a binary neutron star merger in M81 as the progenitor with a confidence of 98%. Neutron star–black hole mergers are excluded with >99% confidence. If the event occurred in M81, then our findings support the hypothesis that GRB 051103 was due to an SGR giant flare, making it one of the most distant extragalactic magnetars observed to date.J. Abadie... J. Hosken... J. Munch... D. J. Ottaway... P. J. Veitch... et al
Swift follow-up observations of candidate gravitational-wave transient events
No full textExtent: 14p.ABSTRACT
We present the first multi-wavelength follow-up observations of two candidate
gravitational-wave (GW) transient events recorded by LIGO and Virgo in their
2009–2010 science run. The events were selected with low latency by the network
of GW detectors (within less than 10 minutes) and their candidate sky locations
were observed by the Swift observatory (within 12 hr). Image
transient detection was used to analyze the collected electromagnetic data,
which were found to be consistent with background. Off-line analysis of the GW
data alone has also established that the selected GW events show no evidence of
an astrophysical origin; one of them is consistent with background and the other
one was a test, part of a “blind injection challenge.” With this work we
demonstrate the feasibility of rapid follow-ups of GW transients and establish
the sensitivity improvement joint electromagnetic and GW observations could
bring. This is a first step toward an electromagnetic follow-up program in the
regime of routine detections with the advanced GW instruments expected within
this decade. In that regime, multi-wavelength observations will play a
significant role in completing the astrophysical identification of GW sources.
We present the methods and results from this first combined analysis and discuss
its implications in terms of sensitivity for the present and future
instruments.P. A. Evans... J. Munch... D. J. Ottaway... P. J. Veitch... et al
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