The Experts below are selected from a list of 36573 Experts worldwide ranked by ideXlab platform
S P Vyatchanin - One of the best experts on this subject based on the ideXlab platform.
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noise in gravitational wave detectors and other classical force measurements is not influenced by test mass quantization
Physical Review D, 2003Co-Authors: V B Braginsky, Andrey B Matsko, M L Gorodetsky, Farid Ya Khalili, K S Thorne, S P VyatchaninAbstract:It is shown that photon shot noise and radiation-pressure back-action noise are the sole forms of quantum noise in interferometric gravitational wave detectors that operate near or below the standard quantum limit, if one filters the interferometer output appropriately. No additional noise arises from the test masses' initial quantum state or from reduction of the test-mass state due to measurement of the interferometer output or from the uncertainty principle associated with the test-mass state. Two features of Interferometers are central to these conclusions: (i) The interferometer output [the photon number flux [script N]-hat(t) entering the final photodetector] commutes with itself at different times in the Heisenberg picture, [[script N]-hat(t),[script N]-hat(t[prime])] = 0 and thus can be regarded as classical. (ii) This number flux is linear to high accuracy in the test-mass initial position and momentum operators x-hato and p-hato, and those operators influence the measured photon flux [script N]-hat(t) in manners that can easily be removed by filtering. For example, in most Interferometers x-hato and p-hato appear in [script N]-hat(t) only at the test masses' ~1 Hz pendular swinging frequency and their influence is removed when the output data are high-pass filtered to get rid of noise below ~10 Hz. The test-mass operators x-hato and p-hato contained in the unfiltered output [script N]-hat(t) make a nonzero contribution to the commutator [[script N]-hat(t),[script N]-hat(t[prime])]. That contribution is precisely canceled by a nonzero commutation of the photon shot noise and radiation-pressure noise, which also are contained in [script N]-hat(t). This cancellation of commutators is responsible for the fact that it is possible to derive an interferometer's standard quantum limit from test-mass considerations, and independently from photon-noise considerations, and get identically the same result. These conclusions are all true for a far wider class of measurements than just gravitational-wave Interferometers. To elucidate them, this paper presents a series of idealized thought experiments that are free from the complexities of real measuring systems.
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conversion of conventional gravitational wave Interferometers into quantum nondemolition Interferometers by modifying their input and or output optics
Physical Review D, 2001Co-Authors: H J Kimble, Y Levin, Andrey B Matsko, Kip S Thorne, S P VyatchaninAbstract:The LIGO-II gravitational-wave Interferometers (ca. 2006–2008) are designed to have sensitivities near the standard quantum limit (SQL) in the vicinity of 100 Hz. This paper describes and analyzes possible designs for subsequent LIGO-III Interferometers that can beat the SQL. These designs are identical to a conventional broad band interferometer (without signal recycling), except for new input and/or output optics. Three designs are analyzed: (i) a squeezed-input interferometer (conceived by Unruh based on earlier work of Caves) in which squeezed vacuum with frequency-dependent (FD) squeeze angle is injected into the interferometer’s dark port; (ii) a variational-output interferometer (conceived in a different form by Vyatchanin, Matsko and Zubova), in which homodyne detection with FD homodyne phase is performed on the output light; and (iii) a squeezed-variational interferometer with squeezed input and FD-homodyne output. It is shown that the FD squeezed-input light can be produced by sending ordinary squeezed light through two successive Fabry-Perot filter cavities before injection into the interferometer, and FD-homodyne detection can be achieved by sending the output light through two filter cavities before ordinary homodyne detection. With anticipated technology (power squeeze factor e-2R=0.1 for input squeezed vacuum and net fractional loss of signal power in arm cavities and output optical train e*=0.01) and using an input laser power Io in units of that required to reach the SQL (the planned LIGO-II power, ISQL), the three types of interferometer could beat the amplitude SQL at 100 Hz by the following amounts μ≡sqrt[Sh]/sqrt[ShSQL] and with the following corresponding increase V=1/μ3 in the volume of the universe that can be searched for a given noncosmological source: Squeezed input —μ≃sqrt[e-2R]≃0.3 and V≃1/0.33≃30 using Io/ISQL=1. Variational-output—μ≃e*1/4≃0.3 and V≃30 but only if the optics can handle a ten times larger power: Io/ISQL≃1/sqrt[e*]=10. Squeezed varational —μ=1.3(e-2Re*)1/4≃0.24 and V≃80 using Io/ISQL=1; and μ≃(e-2Re*)1/4≃0.18 and V≃180 using Io/ISQL=sqrt[e-2R/e*]≃3.2.
Ernst M Rasel - One of the best experts on this subject based on the ideXlab platform.
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t 3 stern gerlach matter wave interferometer
Physical Review Letters, 2019Co-Authors: Omer Amit, Yair Margalit, O Dobkowski, Zhifan Zhou, Yonathan Japha, Matthias Zimmermann, M A Efremov, Frank A Narducci, Ernst M RaselAbstract:We present a unique matter-wave interferometer whose phase scales with the cube of the time the atom spends in the interferometer. Our scheme is based on a full-loop Stern-Gerlach interferometer incorporating four magnetic field gradient pulses to create a state-dependent force. In contrast to typical atom Interferometers that make use of laser light for the splitting and recombination of the wave packets, this realization uses no light and can therefore serve as a high-precision surface probe at very close distances.
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relativistic effects in atom and neutron interferometry and the differences between them
Physical Review A, 2012Co-Authors: Daniel M Greenberger, Wolfgang P Schleich, Ernst M RaselAbstract:In recent years there has been enormous progress in matter wave interferometry. The Colella-Overhauser-Werner (COW) type of neutron interferometer and the Kasevich-Chu (K-C) atom interferometer are the prototypes of such devices and the issue of whether they are sensitive to relativistic effects has recently aroused much controversy. We examine the question as to what extent the gravitational redshift and the related twin paradox effect can be seen in both of these atom and neutron Interferometers. We point out an asymmetry between the two types of devices. Because of this, the nonvanishing, nonrelativistic residue of both effects can be seen in the neutron interferometer, while in the K-C interferometer the effects cancel out, leaving no residue, although they could be present in other types of atom Interferometers. Also, the necessary shifting of the laser frequency (chirping) in the atom interferometer effectively changes the laboratory into a free-fall system, which could be exploited for other experiments.
R Geiger - One of the best experts on this subject based on the ideXlab platform.
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atom interferometry with top hat laser beams
Applied Physics Letters, 2018Co-Authors: N Mielec, M Altorio, Ranjita Chanu Sapam, D Horville, D Holleville, L A Sidorenkov, R GeigerAbstract:The uniformity of the intensity and the phase of laser beams is crucial to high-performance atom Interferometers. Inhomogeneities in the laser intensity profile cause contrast reductions and systematic effects in Interferometers operated with atom sources at micro-Kelvin temperatures and detrimental diffraction phase shifts in Interferometers using large momentum transfer beam splitters. We report on the implementation of a so-called top-hat laser beam in a long-interrogation-time cold-atom interferometer to overcome the issue of inhomogeneous laser intensity encountered when using Gaussian laser beams. We characterize the intensity and relative phase profiles of the top-hat beam and demonstrate its gain in atom-optic efficiency over a Gaussian beam, in agreement with numerical simulations. We discuss the application of top-hat beams to improve the performance of different architectures of atom Interferometers.The uniformity of the intensity and the phase of laser beams is crucial to high-performance atom Interferometers. Inhomogeneities in the laser intensity profile cause contrast reductions and systematic effects in Interferometers operated with atom sources at micro-Kelvin temperatures and detrimental diffraction phase shifts in Interferometers using large momentum transfer beam splitters. We report on the implementation of a so-called top-hat laser beam in a long-interrogation-time cold-atom interferometer to overcome the issue of inhomogeneous laser intensity encountered when using Gaussian laser beams. We characterize the intensity and relative phase profiles of the top-hat beam and demonstrate its gain in atom-optic efficiency over a Gaussian beam, in agreement with numerical simulations. We discuss the application of top-hat beams to improve the performance of different architectures of atom Interferometers.
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Atom Interferometry with Top-Hat Laser Beams
Appl.Phys.Lett., 2018Co-Authors: N Mielec, M Altorio, Ranjita Chanu Sapam, D Horville, D Holleville, L A Sidorenkov, R GeigerAbstract:The uniformity of the intensity and the phase of laser beams is crucial to high-performance atom Interferometers. Inhomogeneities in the laser intensity profile cause contrast reductions and systematic effects in Interferometers operated with atom sources at micro-Kelvin temperatures and detrimental diffraction phase shifts in Interferometers using large momentum transfer beam splitters. We report on the implementation of a so-called top-hat laser beam in a long-interrogation-time cold-atom interferometer to overcome the issue of inhomogeneous laser intensity encountered when using Gaussian laser beams. We characterize the intensity and relative phase profiles of the top-hat beam and demonstrate its gain in atom-optic efficiency over a Gaussian beam, in agreement with numerical simulations. We discuss the application of top-hat beams to improve the performance of different architectures of atom Interferometers.
Matthew Warden - One of the best experts on this subject based on the ideXlab platform.
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multi channel absolute distance measurement system with sub ppm accuracy and 20 m range using frequency scanning interferometry and gas absorption cells
Optics Express, 2014Co-Authors: John Dale, Ben Richard Hughes, A J Lancaster, Andrew Lewis, A Reichold, Matthew WardenAbstract:We present an implementation of an absolute distance measurement system which uses frequency scanning interferometry (FSI). The technique, referred to as dynamic FSI, uses two frequency scanning lasers, a gas absorption cell and a reference interferometer to determine the unknown optical path length difference (OPD) of one or many measurement Interferometers. The gas absorption cell is the length reference for the measurement system and is traceable to international standards through knowledge of the frequencies of its absorption features. The OPD of the measurement Interferometers can vary during the measurement and the variation is measured at the sampling rate of the system (2.77 MHz in the system described here). The system is shown to measure distances from 0.2 m to 20 m with a combined relative uncertainty of 0.41 × 10⁻⁶ at the two sigma level (k = 2). It will be shown that within a scan the change in OPD of the measurement interferometer can be determined to a resolution of 40 nm.
C Baccigalupi - One of the best experts on this subject based on the ideXlab platform.
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measuring the spectrum of primordial gravitational waves with cmb pta and laser Interferometers
Journal of Cosmology and Astroparticle Physics, 2021Co-Authors: P Campeti, Eiichiro Komatsu, Davide Poletti, C BaccigalupiAbstract:We investigate the possibility of measuring the primordial gravitational wave (GW) signal across 21 decades in frequencies, using the cosmic microwave background (CMB), pulsar timing arrays (PTA), and laser and atomic Interferometers. For the CMB and PTA experiments we consider the LiteBIRD mission and the Square Kilometer Array (SKA), respectively. For the Interferometers we consider space mission proposals including the Laser Interferometer Space Antenna (LISA), the Big Bang Observer (BBO), the Deci-hertz Interferometer Gravitational wave Observatory (DECIGO), the $\mu$Ares experiment, the Decihertz Observatory (DO), and the Atomic Experiment for Dark Matter and Gravity Exploration in Space (AEDGE), as well as the ground-based Einstein Telescope (ET) proposal. We implement the mathematics needed to compute sensitivities for both CMB and Interferometers, and derive the response functions for the latter from the first principles. We also evaluate the effect of the astrophysical foreground contamination in each experiment. We present binned sensitivity curves and error bars on the energy density parameter, $\Omega_{GW}h^2$, as a function of frequency for two representative classes of models for the stochastic background of primordial GW: the quantum vacuum fluctuation in the metric from single-field slow-roll inflation, and the source-induced tensor perturbation from the spectator axion-SU(2) inflation models. We find excellent prospects for joint measurements of the GW spectrum by CMB and space-borne Interferometers mission proposals.
