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RandomFactor [soylentnews.org] writes:

Yale University [yale.edu] Researchers have figured out how to save the stochastic life of Schrödinger's cat. [sciencedaily.com]

Schrödinger's cat is a well-known paradox used to illustrate the concept of superposition -- the ability for two opposite states to exist simultaneously -- and unpredictability in quantum physics. The idea is that a cat is placed in a sealed box with a radioactive source and a poison that will be triggered if an atom of the radioactive substance decays. The superposition theory of quantum physics suggests that until someone opens the box, the cat is both alive and dead, a superposition of states. Opening the box to observe the cat causes it to abruptly change its quantum state randomly, forcing it to be either dead or alive

The "quantum jump" is the discrete and random collapse from uncertainty into a single reality when observed.

The experiment, performed in the lab of Yale professor Michel Devoret and proposed by lead author Zlatko Minev, peers into the actual workings of a quantum jump for the first time. The results reveal a surprising finding that contradicts Danish physicist Niels Bohr's established view -- the jumps are neither abrupt nor as random as previously thought.

Quantum jumps were theorized originally by Bohr in 1913 [tandfonline.com], but not observed [aps.org] until [aps.org] the 1980s [aps.org]. These jumps occur every time a qubit is measured.

"Despite that," added Minev, "We wanted to know if it would be possible to get an advance warning signal that a jump is about to occur imminently."

In the experiment,

Microwave radiation stirs [a superconducting artificial three-level atom] as it is simultaneously being observed, resulting in quantum jumps. The tiny quantum signal of these jumps can be amplified without loss to room temperature. Here, their signal can be monitored in real time. This enabled the researchers to see a sudden absence of detection photons (photons emitted by an ancillary state of the atom excited by the microwaves); this tiny absence is the advance warning of a quantum jump.

"The beautiful effect displayed by this experiment is the increase of coherence during the jump, despite its observation," said Devoret. Added Minev, "You can leverage this to not only catch the jump, but also reverse it."

The ability to reverse the quantum jump is crucial according to the researchers

While quantum jumps appear discrete and random in the long run, reversing a quantum jump means the evolution of the quantum state possesses, in part, a deterministic and not random character; the jump always occurs in the same, predictable manner from its random starting point.

The findings which demonstrate that each completed jump is "continuous, coherent and deterministic" have potential application in quantum systems, quantum error correction and veterinary science.

Journal Reference:
Z. K. Minev, S. O. Mundhada, S. Shankar, P. Reinhold, R. Gutiérrez-Jáuregui, R. J. Schoelkopf, M. Mirrahimi, H. J. Carmichael, M. H. Devoret. To catch and reverse a quantum jump mid-flight. Nature, 2019; DOI: 10.1038/s41586-019-1287-z [doi.org]

Original Submission