**Abstract**
The famous "quantum jump" of an atom from one level to another was first postulated by Bohr in 1913, nearly 100 years ago. Can there still be anything interesting to say about quantum jumps in a two-level atom today, nearly 100 years later? Of course my answer is "yes", as I will be talking about two recent papers in this area [1,2]. The most recent [2] proposes experiments to definitively prove that quantum jumps are not due to emission of a photon, but rather to detection. Such a test is possible because different types of detection lead to different types of jumps. The other [1] shows that this flexibility in causing jumps of different types can be used creatively to make an atom jump between a two fixed states even when it is coherently driven by a laser.

[1]R. Karasik and H. M. Wiseman

How Many Bits Does It Take to Track an Open Quantum System?

Phys. Rev. Lett. 106, 020406 (4 pages) (2011)

http://prl.aps.org/abstract/PRL/v106/i2/e020406

[2] Howard M. Wiseman and Jay M. Gambetta

Are Dynamical Quantum Jumps Detector-Dependent?

Phys. Rev. Lett. *108*, 220402 (5 pages) (2012).