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New directions for terrestrial detectors

Explore the innovative ideas and advancements in terrestrial detectors for the next decade. From sub-quantum-limited interferometers to cryogenic and subterranean detectors, discover the possibilities of quantum mechanics and radiation pressure manipulation. Join us on this journey of squeezing the best kind of squeezed states.

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New directions for terrestrial detectors

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  1. New directions forterrestrial detectors The next ten years… Rai’s party, October 2007 Nergis Mavalvala (just a middle child)

  2. Rai-isms • Zacharias’s picture • “This isn’t half stupid” = brilliant! • “What do you know how to do?”“Well, I’ve taken 8.07, 8.08,…, 8.321…”“Oh come off it, what do you really know?”“Err, I can machine.”“You’re alright” • Squash or swimming?

  3. Rai-isms • “I gotta pee, walk with me to the boy’s room.” (At door) “Err…”“Unh, you can’t come with me. I’ll be right out” (1991) • “Rai, I can’t read your annotation here”(Long pause, staring at page)“I can’t read it either” (1996) • Q: ”What’s a reasonable start-up to ask for, Rai?”A: “I think it’ll be hard to go for more than $50,000” (2001)

  4. Because Rai is never really going to retire Why do we need new directions?

  5. The ideas out there…Will they work, or are we crazy? • Sub-quantum-limited interferometers • Novel classical readouts • Quantum mechanical antics • Subterranean interferometers • Cryogenic detectors

  6. Radiationpressure noise Shot noise Quantum noise limited Weiss LIGO Advanced LIGO

  7. Sub-quantum interferometers

  8. Quantum mechanics of light • Heisenberg Uncertainty Principle for EM field • Coherent state(laser light) • Squeezed state • Two complementary observables • Make on noise better for one quantity,BUT it gets worse for the other X+ and X- associated with amplitude and phase McKenzie

  9. First proposed …C.M. Caves, PR D (1981) Proof-of-principle demonstration …M. Xiao et al., PRL (1987) More realistic configurations demonstrated … Power Recycled Michelson K. McKenzie et al., PRL (2002) Power and Signal Recycled MichelsonH. Vahlbruch et al., PRL (2005) Suspended prototypeGoda et al. (2007) X- X- X- X+ X- X+ X+ X+ Quantum Noise in an Interferometer Laser

  10. Squeezed input

  11. Squeeze Source Squeezed Input Interferometer GWDetector Laser Faraday isolator Squeeze Source HomodyneDetector GW Signal

  12. X- X+ Sub-quantum-limited interferometer Narrowbandunsqueezed Broadbandunsqueezed BroadbandSqueezed Quantum correlations Input squeezing

  13. Squeezing injected @ the 40m prototype @ Caltech Goda et al. (2007)

  14. 40m squeezing gang

  15. High laser power radiation pressure ↔ mechanical oscillator coupling

  16. Radiation-mirror coupling 1. Light with amplitude fluctuations DA incident on mirror Movable mirror Remember LLAMA? 2. Radiation pressure due to DA causes mirror to move by Dx 3. Phase of reflected lightDf depends on mirror position and hence light amplitude, i.e DADx  Df

  17. Key ingredients Low mass, low noise mechanical oscillator mirror – 1 gm with 1 Hz resonant frequency High circulating power – 10 kW High finesse cavities10000 Differential measurement – common-mode rejection to cancel classical noise Optical spring – noise suppression and frequency independent squeezing A radiation pressure dominated interferometer

  18. Like atoms Observable quantum effects • Squeezed states of light • Entanglement due to mirror motion • Quantum radiation pressure noise • Squeezed states of the mirror Figure of merit for quantumnessThermal occupation number Optical cooling and trapping of the mini-mirror

  19. Classical radiation pressure effects Stiffer than diamond 6.9 mK Stable OS Optical cooling Radiation pressure dynamics

  20. Quantum radiation pressure effects Entanglement Squeezing Mirror-light entanglement Squeezed vacuum generation

  21. Radiation pressure gang Dave Ottaway Nick Smith Rai’s door art Tim Bodiya

  22. Novel readouts Evading the back action noise radiation pressure

  23. Novel readouts • Speedmeters • Measure momentum, not position • “Optical bar” and “optical lever” configurations • Use radiation pressure to transfer the motion of end masses to vertex for local readout • Intra-cavity readouts • Potential to operate at high sensitivity with much lower power than conventional interferometers

  24. Subterranean detectors

  25. Get off the ground! Density perturbations  fluctuatinggravitational forces You can’t walkbut roller skatesare fine

  26. Cryogenic detectors

  27. Intrinsic material loss LCGT Optical coatings I. Martin et al (2006) Beating down thermal noise

  28. In closing… • Very much in the future • Cryogenics • Subterranean or space observatories • Coming soon(er) to an observatory near you • Quantum radiation pressure manipulation • Squeezing The best kind of squeezed state

  29. The best kind of squeezed states

  30. Annual Lab Hike Tomorrow White MountainsAll are invited

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