Quantum entanglement has the potential to revolutionize the entire field of interferometric sensing by providing
many orders of magnitude improvement in interferometer sensitivity. The quantum-entangled particle interferometer
approach is very general and applies to many types of interferometers. In particular, without nonlocal
entanglement, a generic classical interferometer has a statistical-sampling shot-noise limited sensitivity that scales
N, where N is the number of particles passing through the interferometer per unit time. However, if
carefully prepared quantum correlations are engineered between the particles, then the interferometer sensitivity
improves by a factor of √N
to scale like 1/N, which is the limit imposed by the Heisenberg Uncertainty Principle.
For optical interferometers operating at milliwatts of optical power, this quantum sensitivity boost corresponds
to an eight-order-of-magnitude improvement of signal to noise. This effect can translate into a tremendous science
pay-off for space missions. For example, one application of this new effect is to fiber optical gyroscopes
for deep-space inertial guidance and tests of General Relativity (Gravity Probe B). Another application is to
ground and orbiting optical interferometers for gravity wave detection, Laser Interferometer Gravity Observatory
(LIGO) and the European Laser Interferometer Space Antenna (LISA), respectively. Other applications are to
Satellite-to-Satellite laser Interferometry (SSI) proposed for the next generation Gravity Recovery And Climate
Experiment (GRACE II).