There's no such thing as empty space
Through the Dynamical Casimir Effect, scientists have stimulated a
vacuum to shed some of the myriad 'virtual' particles that fleet in and
out of existence, making them real and detectable.
Scientists claim to have produced particles of light out of vacuum,
proving that space is not empty.
An international team says that its ingenious experiment in which
tiny parcels of light, or photons, are produced out of empty space has
confirmed that a vacuum contains quantum fluctuations of energy, the
'Nature' journal reported.
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An image of the Messier 78 galaxy.
Scientists have recreated the dynamical Casimir effect,
theorised over 40 years ago. AP |
In fact, the scientists have demonstrated for the first time a
strange phenomenon known as the dynamical Casimir effect, or DCE for
short.
The DCE involves stimulating the vacuum to shed some of the myriad
"virtual" particles that fleet in and out of existence, making them real
and detectable. Moreover, the real photons produced by the DCE in their
experiment collectively retain a peculiar quantum signature that
ordinary light lacks.
The research, led by Chris Wilson of Chalmers University of
Technology in Sweden, shows that a related dynamic effect can occur when
such a mirror moves very fast through the vacuum. The DCE was predicted
over 40 years ago, but had not yet been observed experimentally due to
the difficulty of creating the required experimental conditions.
"The DCE was conceived as a kind of thought experiment, sort of like
Schrodinger's Cat. According to quantum theory, if one could accelerate
a mirror very quickly to near the speed of light, the mirror would
radiate light as some of the mirror's motional energy is imparted to
virtual photons lurking in the vacuum, converting them into real
photons.
"But it is practically impossible to accelerate a massive mirror to
such high velocities. The required accelerations would be greater than
the kind of shocks found in supernova or nuclear weapons explosions,"
said team member Prof Tim Duty.
Instead, the scientists set out to demonstrate the DCE using
microwaves, like those used for mobile phone and wireless communication
signals. And instead of a massive mirror, they used a tiny microcircuit
called a Superconducting Quantum Interference Device, or SQUID.
The SQUID acts as a tunable mirror for virtual microwave photons,
fooling them into behaving as if they encountered a moving mirror when
in fact nothing is physically moving.
Furthermore, they had to cool the experiment to a small fraction of a
degree above absolute zero in order to get rid of unwanted thermal
microwaves that would mask the DCE.
"The fact that the quantum vacuum is not empty, as demonstrated in
our experiment, is related to lots of other interesting effects such as
Hawking radiation of black holes and the Lamb shift in atomic physics,"
Prof Duty said. PTI
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