Extracting something from nothing: A bright glow from empty space

space
Credit: CC0 Public Domain

Particles travelling through empty space can emit bright flashes of gamma rays by interacting with the quantum vacuum, according to a new study by researchers at the University of Strathclyde.

It has long been known that charged particles, such as electrons and protons, produce the electromagnetic equivalent of a sonic boom when their speeds exceed that of photons in the surrounding medium. This effect, known as Cherenkov emission, is responsible for the characteristic blue glow from water in a nuclear reactor, and is used to detect particles at the CERN Large Hadron Collider.

According to Einstein, nothing can travel faster than light in vacuum. Because of this, it is usually assumed that the Cherenkov emission cannot occur in vacuum. But according to , the vacuum itself is packed full of "virtual particles", which move momentarily in and out of existence.

These ghostly particles are usually not observable but, in the presence of extremely strong electric and magnetic fields, they can turn the vacuum into an optical medium where the speed of light is slowed down so that charged particles can emit Cherenkov gamma rays. This is totally unexpected in a vacuum.

A group of physics researchers at Strathclyde have found that in extreme conditions, such as found at the focus of the world's most powerful lasers, and the huge magnetic fields around neutron stars, this 'polarised' vacuum can slow down gamma rays just enough for Cherenkov emission to occur. This means that the highest energy cosmic rays passing through the magnetic fields surrounding pulsars should predominantly emit Cherenkov radiation, vastly in excess of other types such as synchrotron radiation.The research has been published as an Editors' Suggestion in Physical Review Letters. It formed part of the EPSRC funded Lab in a Bubble project led by Professor Dino Jaroszynski, to investigate a suite of fundamental phenomena occurring in laser-plasma interactions, with applications in industry, security and medicine.

Professor Jaroszynski said: "The Lab in a Bubble project is providing a unique opportunity to use lasers to advance both fundamental knowledge and advanced technology for the benefit of society."This is a very exciting new prediction because it could provide answers to basic questions such as what is the origin of the gamma ray glow at the centre of galaxies? Also, it provides a new way of testing some of the most fundamental theories of science by pushing them to their limits.

"What is more, it will make a major contribution to the new High Field frontier of physics, made possible by the remarkable advances in laser technology which gained the award of the 2018 Nobel Prize in Physics."Dr. Adam Noble, who conceived the idea and led the theoretical research effort, said: We take it for granted that nothing can come out of empty space consisting of pure . But this is not quite true; modern quantum physics says otherwise, and there are some intriguing surprises.

"There is a huge international effort to push forward the limits of laser technology. While this is driven by the many practical applications of high power lasers, its success will depend on understanding all the fundamental processes involved in laser-matter interactions. These results reveal a new aspect of these processes."

Alexander Macleod, who also worked on the project as part of his Ph.D. project, said: "Quantum electrodynamics is one of the best tested theories in physics, with extraordinary agreement between theoretical predictions and experimental data. But this agreement has only been verified in the weak-field regime. Vacuum Cherenkov radiation offers a new way to test whether it survives in the strong-field limit."

Lab in a Bubble is a £4.5million Strathclyde-led, EPSRC-funded project for the production of bubble-sized 'laboratories' which could boost cancer treatment, medical imaging and industrial processes, in addition to enabling the investigation of fundamental physics problems.

Researchers in the international project aim to use high-powered lasers to conduct experiments in plasma bubbles so small that their diameters are equivalent to one tenth of the cross-section of a human hair. Plasma forms 99.999% of visible matter in the universe.


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More information: Alexander J. Macleod et al, Cherenkov Radiation from the Quantum Vacuum, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.122.161601
Journal information: Physical Review Letters

Citation: Extracting something from nothing: A bright glow from empty space (2019, April 25) retrieved 21 October 2019 from https://phys.org/news/2019-04-bright-space.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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Apr 25, 2019
This is total nonsense; the field about each charge at any instant in time and space is properly defined, i.e. it is updated at the speed of light relative to its center! Once must define proper motion that defines gamma rays neutrinos, and other misnomers!

Apr 25, 2019
But according to quantum theory, the vacuum itself is packed full of "virtual particles", which move momentarily in and out of existence

And as such, quantum theory is pseudoscientific claptrap.
We take it for granted that nothing can come out of empty space consisting of pure vacuum.

We take it for granted that scientists know space is not a "pure vacuum", for about 100-years now. Space is plasma, plasmas experience glow mode, it's why space can glow.

Apr 26, 2019
The idea that a particle moving through the vacuum can emit Cherenkov radiation seems to contradict the principle that all motion is relative. What am I missing?

Apr 26, 2019
"...the vacuum itself is packed full of "virtual particles", which move momentarily in and out of existence."

LOL...such crap.

A magnetic field can also be called a dielectric field, perhaps that is what they mean by polarized vacuum? It's hard to figure out wtf with all the non-sense used.

Apr 26, 2019
But according to quantum theory, the vacuum itself is packed full of "virtual particles", which move momentarily in and out of existence

And as such, quantum theory is pseudoscientific claptrap.
We take it for granted that nothing can come out of empty space consisting of pure vacuum.

We take it for granted that scientists know space is not a "pure vacuum", for about 100-years now. Space is plasma, plasmas experience glow mode, it's why space can glow.


Glow mode! Lol.

Apr 27, 2019
Apparently you can you can get something from nothing

According
to phys.org - Particles travelling through empty space can emit bright flashes of gamma rays by interacting with this quantum vacuum
as
this question was poised some time past
but we digress

Charged particles, electrons and protons, produce an electromagnetic sonic boom
when their speeds exceed that of photons in the surrounding medium
This effect, known as Cherenkov emission
is
responsible for the characteristic blue glow from water in a nuclear reactor
and
is used to detect particles at the CERN Large Hadron Collider

Cherenkov radiation: an electromagnetic radiation emitted when a charged particle passes through a dielectric medium at a speed greater than the phase velocity of light in that medium

so
it appears it is possible
to
Truly get something from nothing
https://en.wikipe...adiation

Apr 27, 2019
Apparently you can you can get something from nothing

Or
It could simply be
electrons interacting with electromagnetic and gravitational force and energy occupying this vacuum
as
the characteristic blue glow from water in a nuclear reactor
is
the hydrogen and oxygen forming water molecules occupying this vacuum
as
nothing comes from nothing because
a vacuum
whether galactic size or quantum size is the same vacuum
because
this vacuum cannot be stretched or compressed
A quantum vacuum is likened to half a hole, impossible as half a vacuum!

Apr 27, 2019
Apparently you can you can get something from nothing
Or
It could simply be
... that you are
using
some weird old DOS
text-
editor that doesn't understand
line-breaks and word wrap...

Apr 27, 2019
The idea that a particle moving through the vacuum can emit Cherenkov radiation seems to contradict the principle that all motion is relative. What am I missing?
Motion relative to masses in different reference-frames. Magnetic and electric fields have no mass, and hence no reference frames.
What does puzzle me is the reference to gamma-rays (=photons) emitting Cherenkov radiation; the latter is elicited by actual matter particles, going through a medium faster than the (local) speed of light.

Apr 28, 2019
It is called, danR
Apparently you can you can get something from nothing
Or
It could simply be
danR> ... that you are
using
some weird old DOS
text-
editor that doesn't understand
line-breaks and word wrap...

Maximisation
maximising our 1000 textual characters
as
Being used to a 1000 textual words, every full stop and comma is eliminated when not required, danR

Apr 28, 2019
required, danR

preferring writing one
unintelligible
post
instead of two   r e a d a b l y   formatted ones.

Apr 29, 2019
The idea that a particle moving through the vacuum can emit Cherenkov radiation seems to contradict the principle that all motion is relative. What am I missing?
That it's not vacuum, i.e. total absence of matter. There's that pesky one atom per cubic meter.

Apr 29, 2019
@danR, you should watch it try to avoid showing a rigorous solution to

2 + 2 / 2 = ?

It's afraid to put up a rigorous solution because it's too stupid to know if it's wrong.

Risible.

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