Physicists study the quantum vacuum

[wolram]

https://www.sciencedaily.com/releases/2017/01/170118132244.htm

I read this with a degree of skepticism, can we manipulate the quantum back ground?

An important step towards a completely new experimental access to quantum physics has been made by researchers in Germany. The team of scientists has now shown how to manipulate the electric vacuum field and thus generate deviations from the ground state of empty space which can only be understood in the context of the quantum theory of light.

 

[fresh_42]

Here's the published paper (however not for free, only the abstract)

http://www.nature.com/nature/journal/v541/n7637/full/nature21024.html

 

[A. Neumaier]

I read this with a degree of skepticism, can we manipulate the quantum back ground?

the researchers from the field of ultrafast phenomena and photonics build on their earlier findings, published in October 2015 in the scientific journal Science, where they have demonstrated direct detection of signals from pure nothingness.

This is journalistic exaggeration. Nobody can make experiments with pure nothingness since whatever is doen is generated by experimental equipment or by the observed environment.

The misunderstanding comes from the fact that in the quantum optics of a beam splitter (which in theory has two input and two output beams) one models a missing input beam by a state containing zero photons, which is the ground state of the corresponding harmonic oscillator. And taking over a notion from quantum field theory, they call the ground state the vacuum state. Thus the input of a beam splitter fed by one laser beam is in the model a tensor product of a coherent state and a vacuum state, and this can be manipulated.

''Vacuum'' therefore just refers to the absence of a beam in part of the experimental arrangement. But to make headlines in the press, this is too little exciting, and Science News uses the well-oiled machinery of the quantum magicians and sells a historically sanctioned misunderstanding for the real thing.

 

[wolram]

Thank you Neumaeir.

 

[A. Neumaier]

The scientific version of the paper is called ''Direct sampling of electric-field vacuum fluctuations'' (Science 23 Oct 2015: Vol. 350, Issue 6259, pp. 420-423). It is more moderate in its claims, though the web page linked to pushes its publicity by introducing it with the popular vacuum fluctuation myth.

 

[A. Neumaier]

The paper mentioned in the previous post is discussed in detail in my new Insight articel
Vacuum Fluctuations in Experimental Practice.