From
CNRS News:
Touching on vacuum energy by
Mathieu Grousson
(picture:© IJCLab/Experience DeLLight)
According to quantum theory, a vacuum is actually packed full of energy. Scientists are currently working on an experiment designed to show that it can even slow light down and deflect it.
...
A paradoxical energy: Even in the earliest versions of quantum mechanics at the beginning of the twentieth century, the equations of the new theory introduced mathematical terms that baffled physicists...
(picture: © SPL/GIROSCIENCE)
... In the following decades, with the advent of quantum electrodynamics, physicists realised that even when space has been emptied of any substance, it seethes with so-called “virtual” particles that constantly pop in and out of existence, emerging from the recesses of space-time and then vanishing without trace. But however virtual these particles may be, they are nonetheless associated with an energy, called vacuum energy, whose effects are very real...
The truth is that, on a theoretical level, the situation is
somewhat problematical, since calculations show that the energy of the
vacuum is infinite...
However, the most astonishing phenomenon is undoubtedly the vacuum effect predicted by Heisenberg and Euler in 1936. In the presence of an extremely powerful magnetic field, it is as if the vacuum acquired a kind of materiality: when light travels through it, it slows down and its path is deflected, exactly as if it were passing through a lens. “In a way, it's rather as if the vacuum became denser when subjected to an intense magnetic field,” Sarazin explains ... Stranger still, around ten years ago Chernodub worked out that under the effect of a magnetic field of around 1020 teslas, the vacuum should behave like a superconducting solid, in other words a material that an electric current travels through without any resistance. “It's baffling,” he says... “Our goal is to show the extent to which, as soon as we
start to delve into the vacuum, we touch on the foundations as well as
the limits of our understanding of the material Universe.”...
...If successful [DeLLight experiment], it would bring us face to face with all the
oddity of the quantum vacuum.” And in this instance, with the fact
that, under certain conditions, a vacuum acquires properties that are
normally those of matter...
...The vacuum thus tells us there is something in the material Universe that completely escapes us. About fifteen years ago, Alvaro de Rujula, at the CERN Department of Theoretical Physics in Geneva (Switzerland), said in jest that the vacuum catastrophe is so severe that “any physicist who doesn't spend at least an hour a day working on this problem should be locked up!” Meanwhile the IJCLab physicists working on the DeLLight experiment are set to explore one of the chinks in vacuum’s armour that may point to a way out of the conundrum. In any case, one thing is for sure: with all due respect to Aristotle, it cannot be asserted that Nature abhors a vacuum. Quite the opposite in fact!
