Critical Technology Giant leaps Near-term steps Non-IFO methods Keith Thorne, Katherine Rawlins Giant leaps Near-term steps Non-IFO methods One vs. many Sociological aspects Confusion limit Imagining the Future: Technology summary

Near-term (“known”) steps To beat down low-frequency limits (mechanical) Move underground (int-term) Cryogenic (int-term) Seismic isolation Gravity gradient compensation To beat down quantum limit (optical) Detuning (narrowbanding) Mirror reflectivity Squeezing Laser Frequency Speed meter Probe masses Next generation of bars: dual acoustic Broadband, high-frequency, R&D funded! Imagining the Future: Technology summary

Adv LIGO Detector Performance Zones to improve? Suspension thermal noise Internal thermal noise Newtonian background, estimate for LIGO sites Seismic ‘cutoff’ at 10 Hz Unified quantum noise dominates at most frequencies for full power, broadband tuning 10-22 Initial LIGO 10-23 10-24 10-25 1 Hz 10 Hz 100 Hz 1 kHz D. Shoemaker

Sub-quantum-limited interferometer X+ X- Quantum correlations (Buonanno and Chen) Input squeezing Imagining the Future: Technology summary

Imagining the Future: Technology summary Giant Leaps To leap forward a factor of 100 or more, will need to go beyond groundbased LIGO-in-space (LIGO frequency) Big Bang Observer (frequencies between LIGO and LISA) Discussion of space logistics (orbit, other planets, station-keeping) Imagining the Future: Technology summary

Non-IFO, non-bar methods Pulsar timing (progress) Precision clocks in space (getting there) Matter-wave interferometers (atoms too slow, too few, arms too short) Very high f lasers (optics technology not there yet) Magnetic/gyroscopic Imagining the Future: Technology summary

Imagining the Future: Technology summary Sociological aspects Science must sometimes push for new technology itself (i.e. large superconducting magnets in HEP); is this one of those cases? Not in a position yet to choose something to push. Better to have “100 pairs of eyes” looking for useful advances by others How much long-term R&D? How much speculative vs. directed? MORE! 5-10% (1% is too little) of total investment What is the right balance (short-, long-term) Imagining the Future: Technology summary

Imagining the Future: Technology summary Many or one? Many bandwidths or one bandwidth? One versatile instrument likely to be cheaper? Going to build a versatile instrument first, then build many facilities? Many instruments or one instrument? Pointing resolution will demand many instruments Conclusion: with a constellation of instruments, can be used either individually or as an array (a la radio astronomy) Imagining the Future: Technology summary

Computation and confusion limit Is computing a vital technology we should push? Instrument itself more likely to be limiting factor. When LISA becomes confusion-limited, position resolution will be even more important Without position resolution, can still do “population astronomy” Groundbased will hit this limit 100x better than Adv. LIGO, can borrow techniques Imagining the Future: Technology summary

Off-topic: theoretical crisis What if we detect nothing (when we should see lots)? What if MOND is correct? What if some yet-unknown physics converts gravitons? Situation may be similar to “solar neutrino problem” -- the key is to achieve certainty that the detector is performing as expected. Imagining the Future: Technology summary

Off-topic: the 30-sec sound byte How do we sell GWA to the guy in the elevator? SKA criteria: unique science, appealing to funding agency, appealing to the public People like black holes Some people like supernovae (others don’t) The big bang is cool too 30-minute pitch just as important Everything will change after the first detection Imagining the Future: Technology summary