1 / 24

Holographic Noise in GEO600?

Holographic Noise in GEO600?. Stefan Hild for the GEO600 team 16th ILIAS WG1 meeting, July 2008, Birmingham. Articles on Holographic Noise available on arXiv:. arXiv:astro-ph/0703775v4. arXiv:0706.1999v2 . arXiv:0709.0611v1. arXiv:0710.4153v2. arXiv:0806.0665v2.

fionn
Download Presentation

Holographic Noise in GEO600?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Holographic Noise in GEO600? Stefan Hild for the GEO600 team 16th ILIAS WG1 meeting, July 2008, Birmingham

  2. Articles on Holographic Noise available on arXiv: arXiv:astro-ph/0703775v4 arXiv:0706.1999v2 arXiv:0709.0611v1 arXiv:0710.4153v2 arXiv:0806.0665v2 ILIAS WG1, March 2008

  3. Published article on Holographic Noise ILIAS WG1, March 2008

  4. Contents of this presentation • Attempt to explain: “What is holographic noise?” • Craig’s predictions • Points we (experimentalists) do not understand • Comparison of Craig’s prediction with noise measured in GEO600 • How to go on from here … ILIAS WG1, March 2008

  5. Spacetime • Space time is not continuous, but quantized. • Assumption:smallest length is the Planck wavelength • This gives a fundamental limit for measurements ILIAS WG1, March 2008

  6. Holographic principle • Some recent findings suggest that all information of a 3D world can be encoded in a 2D surface at Planck resolution. • Example: black hole theory suggest that the entropy scales proportional to its area (not its volume!) • Hypothesis: Quantum geometry (spacetime) has only 2+1 dimesions. ILIAS WG1, March 2008

  7. Indeterminancy of transverse Positions • Angles are indeterminate at Planck scale: • Relative Transverse Positions are uncertain. Uncertainty increases at larger separation: ILIAS WG1, March 2008

  8. Holographic shear noise PRD 77, 104031 ILIAS WG1, March 2008

  9. Characteristic of a random walk Time series of a random walk PSD of random walk time series • The spectrum of a random walk is 1/f in ASD. ILIAS WG1, March 2008

  10. Contents of this presentation • Attempt to explain: “What is holographic noise?” • Craig’s predictions • Points we (experimentalists) do not understand • Comparison of Craig’s prediction with noise measured in GEO600 • How to go on from here … ILIAS WG1, March 2008

  11. Craigs Predictions from arXiv:0806.0665v2 • Zero-parameter estimates • GEO600: • LIGO: f < 550Hz f > 550Hz f < 150Hz f > 150Hz ILIAS WG1, March 2008

  12. Contents of this presentation • Attempt to explain: “What is holographic noise?” • Craig’s predictions • Points we (experimentalists) do not understand • Comparison of Craig’s prediction with noise measured in GEO600 • How to go on from here … ILIAS WG1, March 2008

  13. Points we (experimentalists) do not understand Here should some brainstorming take place … We could try to assemble a list of open issues we want to discuss with Craig… For instance: • Isn’t there any averaging (since we use large amounts of photons)? • GEO-spectrum of Holo noise: The Signal-Recycling cavity does not really change the storage times of the light… ILIAS WG1, March 2008

  14. Contents of this presentation • Attempt to explain: “What is holographic noise?” • Craig’s predictions • Points we (experimentalists) do not understand • Comparison of Craig’s prediction with noise measured in GEO600 • How to go on from here … ILIAS WG1, March 2008

  15. GEO’s Mystery noise • For a long time we observe a unexplained noise component in GEO600. • Shows up as a gap between the sum of all known noises (yellow) and the actual senstivity (black). • Details available at: • Mystery-noise-Wiki http://www.sr.bham.ac.uk/dokuwiki/doku.php?id=geonoise:home • http://www.ego-gw.it/ILIAS-GW/WP1docs/hild_231007.ppt • http://www.ego-gw.it/ILIAS-GW/WP1docs/hild1_050308.ppt ILIAS WG1, March 2008

  16. Noise projection including Holographic Noise • Using Holographic noise prediction from arXiv:0806.0665v2 1.6e-22/sqrt(Hz) for f>550 Hz and 1/f below for f<550 Hz. • If Holographic noise prediction is correct, it could explain most of the mystery noise. ... but ... ILIAS WG1, March 2008

  17. ... but ... Please keep in mind: • Eventhough we worked very hard to ensure the correctness of the projections, they might not represent the full truth: • Projections only account for linear noise coupling • Some projections might underestimate the actual noise contribution (frequency noise) • Some noise sources might still be undiscovered • Holographic noise is only one of several potential candidates that might be able to mystery noise… ILIAS WG1, March 2008

  18. Projection including increasedBS thermo refractive noise • Using a BS thermo refactive noise 3.4 times higher than we believe it to be seems to explain the mystery noise as well. ILIAS WG1, March 2008

  19. Contents of this presentation • Attempt to explain: “What is holographic noise?” • Craig’s predictions • Points we (experimentalists) do not understand • Comparison of Craig’s prediction with noise measured in GEO600 • How to go on from here … ILIAS WG1, March 2008

  20. How can we go on from here? • The two main contributor to the GEO sensitivity are mystery noise and shot noise • We can change the tuning of the Signal-Recycling mirror change the shape of the shot noise. Shot noise in GEO600 for different SR detunings ILIAS WG1, March 2008

  21. Statistical analysis • Need to do noise projections at several SR detunings. • Derive shape of mystery noise for the different detunings. • Use Baysian statistics to put a hard number on how well Craigs predictions explain the mystery noise and compare this to numbers how well a 1/f noise or a flat noise can reproduce the mystery noise. Example of earlier mystery noise mea- surements or different SR detunings ILIAS WG1, March 2008

  22. EXTRA SLIDES ILIAS WG1, March 2008

  23. Holographic spacetime • “Relative spacetime positions of events are indeterminate.” • “Spacetime positions defined to the precision of information propagation and measurement allowed by the capacity of Planck wavelength radiation.” • (Planck radiation: UV cutoff at Planck kength) ILIAS WG1, March 2008

  24. L-shape versus triangle arXiv:0706.1999v2 ILIAS WG1, March 2008

More Related