Via Phys.org: Physicists can predict the jumps of Schrodinger's cat (and finally save it) by Yale University
Yale researchers have figured out how to catch and save Schrödinger's
famous cat, the symbol of quantum superposition and unpredictability,
by anticipating its jumps and acting in real time to save it from
proverbial doom. In the process, they overturn years of cornerstone
dogma in quantum physics.
The
discovery enables researchers to set up an early warning system for
imminent jumps of artificial atoms containing quantum information. A
study announcing the discovery appears in the June 3 online edition of
the journal Nature.
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 (non-continuous) and random change in the state when it is 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.
For a tiny object such as an electron, molecule, or an artificial
atom containing quantum information (known as a qubit), a quantum jump
is the sudden transition from one of its discrete energy states to
another. In developing quantum computers, researchers crucially must
deal with the jumps of the qubits, which are the manifestations of
errors in calculations.
The enigmatic quantum jumps were theorized by Bohr a century ago, but not observed until the 1980s, in atoms.
"These jumps occur every time we measure a qubit," said Devoret, the
F.W. Beinecke Professor of Applied Physics and Physics at Yale and
member of the Yale Quantum Institute. "Quantum jumps are known to be
unpredictable in the long run."
"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."
Minev noted that the experiment was inspired by a theoretical
prediction by professor Howard Carmichael of the University of Auckland,
a pioneer of quantum trajectory theory and a co-author of the study.
In addition to its fundamental impact, the discovery is a potential major advance in understanding and controlling quantum information.
Researchers say reliably managing quantum data and correcting errors as
they occur is a key challenge in the development of fully useful
quantum computers...
Full article: https://phys.org/news/2019-06-physicists-schrodinger-cat.html
