We investigate the quantum-mechanical noise in spectroscopic experiments on ensembles of N two-level (or spin-1/2) systems where transitions are detected by measuring changes in state population. By preparing correlated states, here called squeezed spin states, we can increase the signal-to-noise ratio in spectroscopy (by approximately N1/2 in certain cases) over that found in experiments using uncorrelated states. Possible experimental demonstrations of this enhancement are discussed.
Physical Review A
- Pub Date:
- December 1992
- Quantum fluctuations quantum noise and quantum jumps;
- Nonclassical states of the electromagnetic field including entangled photon states;
- quantum state engineering and measurements