Quantum Measurement and Gravitational-Wave Detection
Friday March 3, 2017
|Presenter:||Yanbei Chen, California Institute of Technology|
|Series:||Physics and Astronomy Colloquium|
|Abstract:||After the initial detection of gravitational waves, further improvements of detector sensitivity will be crucial for future progress in gravitational-wave astronomy. At this moment, using laser interferometry, LIGO detectors are able to sense gravitational-wave-induced displacements of 40-kg test masses at the level of 10^-18 meters, within a time scale of ~ 10 milliseconds. This is close to the so-called Standard Quantum Limit, which arises from the trade-off between displacement sensitivity and measurement-induced back action onto momentum --- as dictated by the Heisenberg Uncertainty Principle, when applied to LIGO's macroscopic test masses. This also means these macroscopic objects are starting to behave quantum mechanically. In next-generation detectors, the SQL can be circumvented over a broad frequency band by injecting frequency-dependent squeezed vacuum. More advanced techniques are being conceived to improve detector sensitivity more dramatically.|
|Location:||Room 125, Dane Smith Hall|
Refreshments will be available before the colloquium, at 3:45 pm, in the lobby of Dane Smith Hall.