quantum field theory says:::::: the vacuum state is not truly empty but instead contains fleeting electromagnetic waves and particles that pop into and out of existence.
then sound should travel through vacuum.......do sound travel through vacuum?
Please check what sound is, then, how sound is propagated and detected, then, decide if your question makes any sense...
@ Thierry De Mees ....
my dear Thierry De Mees i am requesting you shall u please elaborate me how sound is propagated and detected, so that i can become scholar like you!
@ Botan Jawdat Abdullah ....
Sound can not travel in a vacuum because there are no particles⟨ 0 | ϕ | 0 ⟩. In space, human ears are not sensitive to detect sound due to much less density of gaseous particles.
do you mean sound travel through vacuum?
Usually one refers to sound as a density wave.
Now the reason why some colleges claim that you should think before asking, is due to the fact that the vacuum is defined as state without any particle density.
So no sound (at least the classical notion of sound) does not travel through the vacuum.
Best
@ Stefan Zitz ...
my dear Stefan Zitz, quantum field theory says:::::: the vacuum state is not truly empty but instead contains fleeting electromagnetic waves and particles that pop into and out of existence.
if there are particle sure there exist particle density so sound does travel through the vacuum?
Well I tried.
I agree, the vacuum is a poorly understood state.
However do you also know that this particles are seen as virtual particles, they literally can not be used to generate traveling waves (unless u posses like infinity energy) :).
And please look into a QFT book, like Peskin Schröder or Ryder or even Itzykson Zuber, the vacuum is actually defined as the empty state. The problem of vacuum fluctuation and bare and dressed couplings is another one. Which has really nothing to do with sound waves.
By the way electromagnetic waves are different from sound waves. I hope this could convince you to at least drop the idea of making sound from vacuum fluctuations.
Best
The interaction with the virtual quanta of the vacuum is very weak and the sound which is an atomic phenomenon reacts very-very weakly with those virtual states. The neutrinos also go through our bodies or the entire Earth with very few or no interactions.
The vacuum polarization has been observed in specific experiments with and atoms. Another interesting case for vacuum efects is the Casimir Effect.
@ s h s hussinsha
I think perhaps the confusion arises due to the identification of the "Torricelli-Vacuum/material vacuum" ( as routinely created in the laboratory by connecting a robust enclosure ( to withstand atmospheric pressure) with a vacuum-pump) with the "Vacuum state" defined in Quantum Field Theory. The standard expt featuring the reduction of sound of a ringing electric-bell placed inside a chamber as the pressure is gradually reduced from within is well known and demonstrates that sound cannot propagate when material-density of the medium drops to negligible value. The QFT-Vacuum, on the other hand, has structure due to particle-anti particle fluctuation ( creation and reabsorption) but such fluctuations occur typically at a length-scale ~ Compton-wave length ( CWL) of the particle and corresponding time-scale ~ CWL/velocity of light. Unless experiments can attain such precision of time/length measurements, the QFT-vacuum appears to be materially empty. However, as has been noted in other answers to your question, modern day high-energy particle colliders have achieved the desirable precision to observe vacuum-structure/ vacuum polarization-effects although it may not perhaps be meaningful for studying sound propagation in such scattering experiments which measure cross-sections.
@Bimal Mahapatra
My dear Bimal Mahapatra, it is acceptable answer from you. I totally agree with your answer.....
Thank you..
i found your question after searching that if anybody has this question or not !!! this is also my question. at first it seems very simple but in reality very very deep question. who is sure that no mechanical wave (such as sound or ultrasound!!) can not propagate in vacuum?! Are the available sensors have enough sensitivity to detect this phenomenon?!!!
in my point of view , quantum vacuum fluctuation can be stronger with presence of mechanical waves. for example, when an ultrasound wave enters a metal, matter fluctuations are occurred and propagate inside the metal to reach the interface with vacuum of outside ( it is assumed that the metal part located in a vacuum chamber). then this wave as atom fluctuation will be reflected (come back). BUT if quantum vacuum fluctuation is real and can propagate inside metal , when reach to interface of metal and vacuum of outside , it can enter to this outside vacuum. i am trying now to prove it. the results will show new aspects of negative energy and also negative mass!!
@ Mojtaba Esmaeilzadeh
my dear Mojtaba Esmaeilzadeh , it is good thinking....
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