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summary
On October 4
, 2022, the Nobel Prize in Physics was decided as follows:
Alain Aspe
Paris Sakurai University and École Polytechnique, Palaiseau, France
John Crowther
J.F. Crowther & Associates, Walnut Creek, California, USA
Anton Seillinger
Austria, University of Vienna
They conducted
groundbreaking experiments on "quantum entanglement" and their results paved the way from theory to technology.
History and background of "quantum entanglement"
The inexplicable effects of quantum mechanics are beginning to be applied.
There are large research areas such as
quantum computers, quantum networks, and secure quantum cryptographic communications.
One of the key factors in these developments is that quantum mechanics has made it possible for two or more particles to exist in
a tangled state.
In quantum mechanics, two or more particles
can exist as a "tangled" state.
For a long time,
there was a question of whether this correlation was due to the fact that the entangled pairs of particles contained hidden variables –
instructions that dictate what results should be obtained in the experiment.
In the 1960s,
John Stewart Bell developed the mathematical inequality that bears his name.
It's called Bell's inequality.
This means that if there is a hidden variable, the correlation of a large number of measurement results will not exceed a certain value.
achievement
John Crowther
John Crowther
developed
John Bell's ideas and connected them to practical experiments.
Specifically, using calcium atoms that can
emit intertwined photons when irradiated with special light,
filters were installed on the left and right sides to
measure the polarization of photons.
When he measured, it
clearly broke Bell's inequality and supported quantum mechanics.
This means that quantum mechanics will not replace theories
that use hidden variables.
Alan Aspe
Even after John Crowther's experiments, some theoretical flaws
remained.
As a way to close defects, Alan Aspe
developed a device that could switch measurement settings after entangled pairs had moved away from the source,
demonstrating that the settings
that existed when the pairs were emitted did not affect the measurement results.
Specifically, they used a new method of exciting atoms to emit intertwined photons at a faster rate,
and
also succeeded in switching to a different setting.
Anton Seillinger
Anton Seillinger
set out to exploit the entanglement of quantum states through
sophisticated tools and long experiments.
In particular, his research group
demonstrated a phenomenon called quantum teleportation, which allows quantum states to be remotely controlled from one particle to another.
Specifically, a laser was irradiated on a special crystal to create
entangled pairs of photons, and the measurement settings were shifted using random numbers,
and the measurement settings were changed using random numbers. In one experiment, signals from distant galaxies were used to control filters and control them so that the signals did not affect each other.
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How entanglement has become a powerful tool
For experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science