MeJennifer said:
Could you reference any experiment that proves that empirically?
Observing the progressive decoherence of the ''meter'' in a quantum measurement
Brune M, Hagley E, Dreyer J, Maitre X, Maali A, Wunderlich C, Raimond JM, Haroche S
Physical Review Letters 77: 4887-4890, 1996
A mesoscopic superposition of quantum states involving radiation fields with classically distinct phases was created and its progressive decoherence observed. The experiment involved Rydberg atoms interacting one at a time with a few photon coherent field trapped in a high Q microwave cavity. The mesoscopic superposition was the equivalent of an ''atom + measuring apparatus'' system in which the ''meter'' was pointing simultaneously towards two different directions - a ''Schrödinger cat.'' The decoherence phenomenon transforming this superposition into a statistical mixture was observed while it unfolded, providing a direct insight into a process at the heart of quantum measurement.
Trapping and coherent manipulation of a Rydberg atom on a microfabricated device: a proposal
John Mozley, Philippe Hyafil, Gilles Nogues, Michel Brune, Jean-Michel Raimond, Serge Haroche
http://arxiv.org/abs/quant-ph/0506101
We propose to apply atom-chip techniques to the trapping of a single atom in a circular Rydberg state. The small size of microfabricated structures will allow for trap geometries with microwave cut-off frequencies high enough to inhibit the spontaneous emission of the Rydberg atom, paving the way to complete control of both external and internal degrees of freedom over very long times. Trapping is achieved using carefully designed electric fields, created by a simple pattern of electrodes. We show that it is possible to excite, and then trap, one and only one Rydberg atom from a cloud of ground state atoms confined on a magnetic atom chip, itself integrated with the Rydberg trap. Distinct internal states of the atom are simultaneously trapped, providing us with a two-level system extremely attractive for atom-surface and atom-atom interaction studies. We describe a method for reducing by three orders of magnitude dephasing due to Stark shifts, induced by the trapping field, of the internal transition frequency. This allows for, in combination with spin-echo techniques, maintenance of an internal coherence over times in the second range. This method operates via a controlled light shift rendering the two internal states' Stark shifts almost identical. We thoroughly identify and account for sources of imperfection in order to verify at each step the realism of our proposal.