The uncertainty principle, first introduced by Werner Heisenberg in the late
1920's, is a fundamental concept of quantum mechanics. In the quantum world,
particles like the electrons that power all electrical product can also
behave like waves. As a result, particles cannot have a well-defined
position and momentum simultaneously. For instance, measuring the momentum
of a particle leads to a disturbance of position, and therefore the position
cannot be precisely defined.

In recent research, published in Science, a team led by Prof. Mika Sillanpää
at Aalto University in Finland has shown that there is a way to get around
the uncertainty principle. The team included Dr. Matt Woolley from the
University of New South Wales in Australia, who developed the theoretical
model for the experiment.

Instead of elementary particles, the team carried out the experiments using
much larger objects: two vibrating drumheads one-fifth of the width of a
human hair. The drumheads were carefully coerced into behaving quantum
mechanically.

"In our work, the drumheads exhibit a collective quantum motion. The drums
vibrate in an opposite phase to each other, such that when one of them is in
an end position of the vibration cycle, the other is in the opposite
position at the same time. In this situation, the quantum uncertainty of the
drums' motion is cancelled if the two drums are treated as one
quantum-mechanical entity", explains the lead author of the study, Dr. Laure
Mercier de Lepinay.

This means that the researchers were able to simultaneously measure the
position and the momentum of the two drumheads - which should not be
possible according to the Heisenberg uncertainty principle. Breaking the
rule allows them to be able to characterize extremely weak forces driving
the drumheads.

"One of the drums responds to all the forces of the other drum in the
opposing way, kind of with a negative mass", Sillanpää says.

Furthermore, the researchers also exploited this result to provide the most
solid evidence to date that such large objects can exhibit what is known as
quantum entanglement. Entangled objects cannot be described independently of
each other, even though they may have an arbitrarily large spatial
separation. Entanglement allows pairs of objects to behave in ways that
contradict classical physics, and is the key resource behind emerging
quantum technologies.

A quantum computer can, for example, carry out the types of calculations
needed to invent new medicines much faster than any supercomputer ever
could.

In macroscopic objects, quantum effects like entanglement are very fragile,
and are destroyed easily by any disturbances from their surrounding
environment. Therefore, the experiments were carried out at a very low
temperature, only a hundredth a degree above absolute zero at -273 degrees.

In the future, the research group will use these ideas in laboratory tests
aiming at probing the interplay of quantum mechanics and gravity. The
vibrating drumheads may also serve as interfaces for connecting nodes of
large-scale, distributed quantum networks.

## Reference:

Quantum mechanics–free subsystem with mechanical oscillators, SCIENCE, Vol
372, Issue 6542, pp. 625-629,
DOI: 10.1126/science.abf5389

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