# Tag Info

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Different vacua will necessarily yield different answers to this question. Also, you would need to actually know what the energy value (vacuum expectatation value) of the vacua we are in actually is. Evidently, we don't. The fact that the Higgs mechanism does not violate conservation of energy in this vacua does not mean that it cannot violate it, nor ...

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What is really being said is that it is not an uncaused event in the vacuum, but in simplistic terms, it could be said to be more a property of the vacuum. No event is taking place as such. Describing it as an event is trying to put it in simplistic terms, which while it may help in understanding to some degree, is not an exact description. You could equally ...

1

The Casimir effect is used as experimental proof of the existence of the vacuum virtual exchanges. The typical example is of two uncharged metallic plates in a vacuum, placed a few micrometers apart. In a classical description, the lack of an external field also means that there is no field between the plates, and no force would be measured between them. ...

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Isn't saying that time doesn't exist without motion equivalent to saying that sound doesn't exist when no one is around to hear it? You can't rule out time's existence in this way. Then again, why focus on time? When you propose an empty space, does space exist? Normally space is detected as a separation between objects. If no objects exists, as per scenario ...

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The vacuum is polarizable. The polarization can be with respect to electric charge or color charge. In the presence of an electric field, virtual electron-positron pairs briefly exist (created from virtual photons of sufficient energy). The virtual pairs act as dipoles and orient with respect to the field. For example, near a proton, the virtual electron ...

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USim can do vacuum + gas http://www.txcorp.com/home/usim/usim-overview. Not technically true vacuum, but 9 orders of magnitude density jumps. It doesn't support an incompressible fluid (liquid) though.

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Perfect vacuum can't be created. Even if you somehow get rid of all material particles, there still will be blackbody photons from the container, not to mention virtual gravitons. Generally, you can't be 100% sure that some part of space is perfect vacuum - to know that you should measure precisely the energy of that region, but it's forbidden by ...

1

Given an ideal piston/cylinder, starting with the piston completely inserted and zero volume, the work to make a perfect vacuum is simply: (distance the piston moves) X (force) = (distance) X (area of the piston) X (exterior pressure). So the work to make a vacuum of volume V, is V X P, where P is the exterior pressure, such as atmospheric pressure. ...

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In quantum scale, particles are appearing and disappearing out of random everywhere all the time, meaning that if you are actually able to create a perfect vacuum at a macro scale, it would be instantly denied by the quantum scale. Also, in the quantum world, there's a small chance of random "teleportation" of any particle or atom from your container to any ...

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The answer is no, or at least it is in the classical vacuum sense. I also don't see a rationale for why creating a vacuum would require infinite energy. An explicit construction is to use a solid-phase reactive chemical "getter" to eliminate (nearly) all gas molecules present; in experimental practice, virtually all man-made materials still outgas ...

2

If the volume between the two containers is a true vacuum (by definition no molecules present), taking away the air inside the inner container would have no effect. The net pressure on the outer container would be atmospheric pressure, since the internal pressure is zero. If the volume between the two containers is only a partial vacuum, and the inner ...

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Both the free and interacting vacuum are invariant under translations, assuming that translation invariance isn't spontaneously broken. Usually we expand around spatially homogeneous and time-independent field configurations, so that you don't have to worry about spontaneously breaking translations. There are some cases where translations are broken in the ...

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I just realized what the problem is. It actually doesn't have anything to do with the detector. When working in vacuum systems you have to worry about the dielectric breakdown of the air as the pressure is reduced. It turns out that the breakdown voltage hits a minimum around $\sim 1$ Torr depending on the species of the gas (see the curves below). This ...

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Assuming you're willing to accept General Relativity as a valid theory, your question has a well defined answer because we can solve the equations of GR for an empty universe. The result (well, the simplest result) is Minkowski spacetime. You might think that nothing much can happen in an empty universe, but even though no matter or energy is present there ...

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In classical field theory, the system will indeed be in the minima of the potential, i.e., the point at which $\partial V/\partial \phi_i=0$ for all fields $\phi_i$ for all fields $\phi_i$ (more precisely one should include the fermionic fields here as well but fermions don't exist in a classical world). In Quantum Field Theory the same applies as above ...

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Now what about something like a gravitational field? Could that also be excluded from acting within a perfect vacuum? As pointed out in this Wikipedia article on gravitational shielding, the ability to shield gravitational fields would violate the equivalence principle which is inconsistent with both Newtonian mechanics and Einstein's general ...

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