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). What the paper says!?
This reports quantum jumps in mercury (Hg⁺), following back-to-back the letter from Sauter et al.[1] and, together with it, the essentially simultaneous report by Nagourney et al.[2].
In contrast to these two papers, they rely on the V, not Λ, scheme, and use two lasers in the scheme that is the closest to the original amplifier concept: one on the strong transition, the other on the weaker quadrupole one.
In absence of the weak-transition driving (panel (a)), the random jumps are problematic (say for dwell-time distributions) and attributed to collisions and $P_{1/2}\to D_{3/2}$ transitions. Panel (b) is the typical result and (c) the case with two ions, so three steps, which they refer to as quantum switching:
In Nagourney et al.[2]'s paper, P₁/₂→D₃/₂ is the leak that requires to repump the Λ scheme. In Hg⁺, that branch is weak enough that they leave it unrepumped and tolerate it as background.
While the driving is coherent, this is also treated by the incoherent excitation (rate equations) model.
They also detect (and report) photon-antibunching from the weak transition:
Because of the quantum amplification in the S-P scattering loop the photon antibunching is detected with nearly 100% efficiency.
They made another paper on this particular finding,[3] which is however flashed here in passing.
They conclude not with prospect for quantum spectroscopy, but something more device-oriented:
It is interesting to speculate about a single atom in which the upper state on the weak transition is extremely long lived and excited by adiabatic rapid passage.20 In this case the random nature of the excitation is eliminated and one could realize a single-atom switch or flip flop.
The transitions they use (194nm for the strong ²S₁/₂→²P₁/₂ cooling/fluorescence and 281.5nm for the weak ²S₁/₂→²D₅/₂ electric-quadrupole line) will indeed later become the foundation for optical frequency standards and atomic clocking.[4]
In the introduction, more applications of electron shelving are listed.
Regarding priority claims:
We note that a Letter by Nagourney, Sandberg, and Dehmelt describing quantum jumps in a single Ba+ atom has appeared subsequent to the submission of our Letter.
References
- ↑ Observation of Quantum Jumps. T. Sauter, W. Neuhauser, R. Blatt and P. Toschek in Phys. Rev. Lett. 57:1696 (1986).
- ↑ 2.0 2.1 Shelved optical electron amplifier: Observation of quantum jumps. W. Nagourney, J. Sandberg and H. Dehmelt in Phys. Rev. Lett. 56:2797 (1986).
- ↑ Photon antibunching and sub-Poissonian statistics from quantum jumps in one and two atoms. W. Itano, J. Bergquist and D. Wineland in Phys. Rev. A 38:559 (1988).
- ↑ An Optical Clock Based on a Single Trapped $^199$Hg$^+$ Ion. S. Diddams, T. Udem, J. Bergquist, E. Curtis, R. Drullinger, L. Hollberg, W. Itano, W. Lee, C. Oates, K. Vogel and D. Wineland in Science 293:825 (2001).