Measurement of the magnetically-induced QED birefringence of the vacuum and an improved search for laboratory axions: Project definition study of the use of assets and facilities of the Superconducting Super Collider Laboratory (original) (raw)
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Classical and Quantum Gravity, 2004
We have built and tested a 3.5 m high-finesse Fabry-Perot prototype inteferometer with a precision ellipsometer for the QED test and axion search (Q & A) experiment. We use X-pendulum-double-pendulum suspension designs and automatic control schemes developed by the gravitational-wave detection community. Verdet constant and Cotton-Mouton constant of the air are measured as a test. Double modulation with polarization modulation 100 Hz and magneticfield modulation 0.05 Hz gives 10 −7 rad phase noise for a 44-minute integration.
Feasibility study of an experiment to measure the vacuum magnetic birefringence
Czechoslovak Journal of Physics, 2005
The use of a recently decommissioned 15-meters long twin aperture LHC supercon-ducting magnet prototype having a transverse magnetic fieldB ≈ 9.5 T provides the unique opportunity for the construction of a new powerful experiment to measure the Vacuum Magnetic Birefringence (VMB). The values or the limit values of the mass and of the coupling constant to two photons of possible dark matter candidates such as axions are aimed to be deduced from such an experiment. In this article, the technical feasibility study of a new setup to measure the VMB will be presented. It is based on a linear optical resonant cavity house in the LHC superconducting dipole prototype. The mechanical integrations of the optical components inside the magnet aperture as well as the optical detection principles will be presented. A comparison of the expected performances with respect to the present reference results for this type of experiment will also be given.
The next detectors for gravitational wave astronomy
Science China Physics, Mechanics & Astronomy, 2015
This paper focuses on the next detectors for gravitational wave astronomy which will be required after the current ground based detectors have completed their initial observations, and probably achieved the first direct detection of gravitational waves. The next detectors will need to have greater sensitivity, while also enabling the world array of detectors to have improved angular resolution to allow localisation of signal sources. Sect. 1 of this paper begins by reviewing proposals for the next ground based detectors, and presents an analysis of the sensitivity of an 8 km armlength detector, which is proposed as a safe and cost-effective means to attain a 4-fold improvement in sensitivity. The scientific benefits of creating a pair of such detectors in China and Australia is emphasised. Sect. 2 of this paper discusses the high performance suspension systems for test masses that will be an essential component for future detectors, while sect. 3 discusses solutions to the problem of Newtonian noise which arise from fluctuations in gravity gradient forces acting on test masses. Such gravitational perturbations cannot be shielded, and set limits to low frequency sensitivity unless measured and suppressed. Sects. 4 and 5 address critical operational technologies that will be ongoing issues in future detectors. Sect. 4 addresses the design of thermal compensation systems needed in all high optical power interferometers operating at room temperature. Parametric instability control is addressed in sect. 5. Only recently proven to occur in Advanced LIGO, parametric instability phenomenon brings both risks and opportunities for future detectors. The path to future enhancements of detectors will come from quantum measurement technologies. Sect. 6 focuses on the use of optomechanical devices for obtaining enhanced sensitivity, while sect. 7 reviews a range of quantum measurement options.
Letter of Intent QED Test and Axion Search by means of Optical Techniques To the CERN SPSC
2006
The re-use of recently decommissioned 15-meter long twin aperture LHC superconducting magnet prototypes, providing a transverse magnetic field B ≈ 9.5 T offers a unique opportunity for the construction of a new powerful two-in-one experiment to investigate the properties of the vacuum by means of optical techniques. Linearly polarised laser light beams will be used as probes inside vacuum chambers housed inside superconducting magnet apertures. One of the apertures will be dedicated to the measurements of the Vacuum Magnetic Birefringence (VMB) and optical absorption anisotropy whereas the other one will be used to detect the photon regeneration from axions or axion-like particles using “a shining light through the wall”. The VMB predicted by the QED theory is expected to be measured for the first time and the CPT symmetry precisely tested. The values or the limiting values of mass and coupling constant to two photons of weakly interacting scalar or pseudo-scalar particles like axio...
Improving ellipticity detection sensitivity for the Q & A vacuum birefringence experiment
Q & A (quantum electrodynamics test and search for axion) experiment was first proposed in 1994 and a 3.5 m high-finesse Fabry-Perot prototype detector extendable to 7 m has been built and tested. We now enter into the 2nd phase of improving the ellipticity detection sensitivity. We present our scheme, compare with other ongoing experiments, analyze the displacement spectra of our suspension system, and use them for designing automatic alignment control to improve the ellipticicy detection sensitivity. To improve ellipsometry resolution, we use new polarizers of extinction ratio smaller than 10^{-8}.
Optical Search for QED vacuum magnetic birefringence, Axions and photon Regeneration
cdsweb.cern.ch
Since its prediction in 1936 by Euler, Heisenberg [3] and Weisskopf [4] in the earlier development of the Quantum Electrodynamic (QED) theory, the Vacuum Magnetic Birefringence (VMB) is still a challenge for optical metrology techniques. According to QED [5], the vacuum behaves as an optically active medium in the presence of an external magnetic field. It can be experimentally probed with a linearly polarized laser beam [6]. After propagating through the vacuum submitted to a transverse magnetic field, the polarization of the laser beam will change to elliptical and the parameters of the polarization are directly related to fundamental constants such as the fine structure constant and the electron Compton wavelength. Contributions to the VMB could also arise from the existence of light scalar or pseudoscalar particles like axions that couple to two photons and this would manifest itself as a sizeable deviation from the initial QED prediction [7]. On one side, the interest in axion search, providing an answer to the strong-CP problem lies beyond particle physics since such hypothetical neutral light spinzero particle is considered as one of the good dark matter candidates, and the only non-supersymmetric one. The cosmological problems concerning dark matter and dark energy could then profit from results obtained from the purely laboratory experiment proposed in this document. On the other side, the domain of physics that will be investigated with this project is guaranteed by the QED vacuum polarization. The test of QED by measuring a predicted ellipticity of the order of 2x10-11 rad for a light beam propagating over ~ 25 km in a 9.5 T field constitutes the best test of a theory never achieved so far i.e. at the level of ∼10-22 that corresponds to the absolute relative change of the vacuum refractive index.
Light and/or atomic beams to detect ultraweak gravitational effects
EPJ Conferences 74, 03001, 2014
The opportunities lent by ring lasers and atomic beams interferometry in order to reveal gravitomagnetic effects on Earth are reviewed. Both techniques are based on the asymmetric propagation of waves in the gravitational field of a rotating mass; actually the times of flight for co- or counter-rotating closed paths turn out to be different. After discussing properties and limitations of the two approaches we shall describe the proposed GINGER experiment which is being developed for the Gran Sasso National Laboratories in Italy. The experimental apparatus will consist of a three-dimensional array of square rings, 6m × 6m, that is planned to reach a sensitivity in the order of 1prad/√Hertz or better. This sensitivity would be one order of magnitude better than the best existing ring, which is the G-ring in Wettzell, Bavaria, and would allow for the terrestrial detection of the Lense-Thirring effect and possibly of deviations from General Relativity. The possibility of using either the ring laser approach or atomic interferometry in a space mission will also be considered. The technology problems are under experimental study using both the German G-ring and the smaller G-Pisa ring, located at the Gran Sasso.
Lasers and optics: looking towards third generation gravitational wave detectors
General Relativity and Gravitation, 2011
Third generation terrestrial interferometric gravitational wave detectors will likely require significant advances in laser and optical technologies to reduce two of the main limiting noise sources: thermal noise due to mirror coatings and quantum noise arising from a combination of shot noise and radiation pressure noise. Increases in laser power and possible changes of the operational wavelength require new high power laser sources and new electro-optic modulators and Faraday isolators. Squeezed light can be used to further reduce the quantum noise while nano-structured optical components can be used to reduce or eliminate mirror coating thermal noise as well as to implement all-reflective interferometer configurations to avoid thermal effects in mirror substrates. This paper is intended to give an overview on the current state-of-the-art and future trends in these areas of ongoing research and development.
Advanced quantum techniques for future gravitational-wave detectors
Living Reviews in Relativity, 2019
Quantum fluctuation of light limits the sensitivity of advanced laser interferometric gravitational-wave detectors. It is one of the principal obstacles on the way towards the next-generation gravitational-wave observatories. The envisioned significant improvement of the detector sensitivity requires using quantum non-demolition measurement and back-action evasion techniques, which allow us to circumvent the sensitivity limit imposed by the Heisenberg uncertainty principle. In our previous review article (Danilishin and Khalili in Living Rev Relativ 15:5, 2012), we laid down the basic principles of quantum measurement theory and provided the framework for analysing the quantum noise of interferometers. The scope of this paper is to review novel techniques for quantum noise suppression proposed in the recent years and put them in the same framework. Our delineation of interferometry schemes and topologies is intended as an aid in the process of selecting the design for the next-generation gravitational-wave observatories.