Shelved optical electron amplifier: Observation of quantum jumps. W. Nagourney, J. Sandberg and H. Dehmelt in Phys. Rev. Lett. 56:2797 (1986). What the paper says!?
The paper reports the first (published, see also [1][2]) experimental observation of "shelving":
no experimental demonstration of the shelved optical electron amplifier, or "shelving" for short, appears to have been published so far. We now report the demonstration of shelving
although in a Λ-looking type systems, as opposed to the Cook-Kimble V type,[3] so that here a more complicated level structure is involved. As a result of $D_{3\over2}$ being there in Barium, a laser is required to keep it "empty" and sending it back to the main 493nm transition, so that the bottom Λ serves as the radiative part and the top one to reach $D_{5\over2}$ serves as the shelf from an incoherently-pumped $P_{3\over2}$ state.
This results in telegraphic noise:
The observation provides the first direct observations of quantum jumps in a single trapped ion:
These experiments have a special fascination, as, in the language of modern quantum mechanics, they allow one to watch the reduction of the wave function by the measurement process on the oscilloscope screen.
And it also demonstrates a «near-unity quantum efficiency» detection of transition to the metastable state, which is otherwise weak (by definition):
Our observations are the first known application of this scheme in the detection of forbidden optical transitions in an individual ion, as originally proposed.
This thus opens a form of high-resolution spectroscopy (at least if replacing the incoherent pumping of their cathode lamp by a laser): «This experiment demonstrates that, even with an extremely low optical transition rate, virtually every transition to the metastable level would be detected.»
Note that the Λ alone with the main laser wouldn't work as the telegraphic noise would be essentially dark, with only few, probably unobservable, sequences of emission.
The following seems to be related to QND:[4]
The reduction process here is demonstrated in a fashion even more striking than the 1976 geonium experiments for spin flips of a single electron via the continuous Stern-Gerlach effect.
Their picture is based on
the simple quantum electrodynamics of Planck, Einstein, and Bohr. In this method, a two-level atom in the thermal radiation field is pictured as instantaneously emitting and absorbing a photon and jumping between the two levels (labeled as 0 and 1) in which it remains with the respective randomly varying dwell times $t_0$ and $t_1$
and they indeed describe everything in terms of memoryless, spontaneous transitions.
How to start a paper:
In 1975, one of the authors briefly described a scheme1 in which the strong resonance fluorescence of an individual atomic ion confined in high vacuum serves as a monitor which determines whether or not the ion is in its electronic ground state.
(their Ref. [1], which is our Ref. [5], doesn't appear to be available. It is part II of a series. Part III is available!)
- ↑ Observation of Quantum Jumps. T. Sauter, W. Neuhauser, R. Blatt and P. Toschek in Phys. Rev. Lett. 57:1696 (1986).
- ↑ Observation of Quantum Jumps in a Single Atom. J. C. Bergquist, R. G. Hulet, W. M. Itano and D. J. Wineland in Phys. Rev. Lett. 57:1699 (1986).
- ↑ Possibility of Direct Observation of Quantum Jumps. R. Cook and H. Kimble in Phys. Rev. Lett. 54:1023 (1985).
- ↑ Continuous Stern-Gerlach effect: Principle and idealized apparatus. H. Dehmelt in Proc. Natl. Acad. Sci. 83:2291 (1986).
- ↑ Proposed $10^{14}\Delta\nu < \nu$ Laser Fluorescence Spectroscopy on Tl${}^+$ Mono-Ion Oscillator II (spontaneous quantum jumps). H. G. Dehmelt in Bull. Amer. Phys. Soc. 20:60 (1975).