Here we'll list and describe ideas for testing 3rd generation (i.e., beyond Advanced LIGO) interferometric techniques at the 40m.

 * Multi-color (multi-springy) interferometers (maybe this is only 2.5G) 

 * Sloshing cavities

 * Long signal cavities

 * speed-meter interferometers

 * [[local_readout_techniques]]

 * injecting squeezed vacuum

 * VRSM

 * super-seismic cancellation (feed-forward from seismometers, gravity gradient cancellation)

 * [[white_light_signal_cavities]]