Can a region of space-time be created with no ER?

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In summary, a photon may be considered as an excitation of the electromagnetic (ER) field. This is thought to be omnipresent/ubiquitous in time-space, but it is possible to construct a region in space-time that contains no ER fields. If the field strength is zero, does that count as "no EM field"? Do you count vacuum fluctuations? If you do, it is impossible.
  • #1
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A photon may be considered as an excitation of the electromagnetic (ER) field.

ER is thought to be omnipresent/ubiquitous in time-space (?)

Is it possible to construct a region in space-time (say a "black" box):1. That contains no ER fields?
2. that contains no photons? i.e. no excitation/energy...just a peaceful region with "calm" ER fields
 
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  • #2
If the field strength is zero, does that count as "no EM field"?
Do you count vacuum fluctuations? If you do, it is impossible (see the Casimir effect).

2. that contains no photons? i.e. no excitation/energy...just a peaceful region with calm ER fields
A small hole in a superconductor, cooled sufficiently... should work.
 
  • #3
I think, as mfb implies, a lot depends on just what you mean:

A photon is a quanta of an electromagnetic field, that is, a locally detectable manifestation of ER... a locally observable field quantity, while the field is a mathematical construct, not observable.

I don't think any ER is detectable in space unless from an external source. I suspect that is what mfb's small hole in a superconductor implies??

This seems contradictory:
1. That contains no ER fields?
2. that contains no photons? i.e. no excitation/energy...just a peaceful region with calm ER fields

Is a 'calm ER field' 'no ER field'...'calm' is not a term I have seen in these forums. Do you make a distinction between 'no ER' and 'no photons' and 'calm ER fields' ??

You are perhaps thinking of 'detectable' ER...??

You can get rid of most detectable ER with a Faraday cage, but your question may go beyond that to vacuum energy.
 
  • #4
A calm field doesn't mean no field just as a calm ocean doesn't mean no water. Anyways, a calm field will happen at zero Kelvin (in classic physics) which is impossible by the 3rd law of Thermodynamics. Clasic physics isn't exact though and in Quantum physics even at zero Kelvin there would be some oscillation left on the fields due to zero point energy
 
  • #5
There will always be virtual photons.
The problem is that a "true vacuum" is too specific and would violate Heisenberg Uncertainty.
 

1. Can a region of space-time exist without an event horizon?

Yes, a region of space-time can exist without an event horizon. An event horizon is a boundary in space-time beyond which events cannot affect an outside observer. However, this does not mean that a region of space-time cannot exist without it. In fact, the majority of space-time does not have an event horizon.

2. What is the significance of the event horizon in the creation of a region of space-time?

The event horizon is significant in the creation of a region of space-time because it marks the boundary beyond which no information or events can be observed by an outside observer. This means that the conditions within the event horizon cannot be studied or understood by those outside of it.

3. Can a region of space-time be created without an event horizon in the future?

Yes, a region of space-time can be created without an event horizon in the future. The formation of an event horizon depends on the mass and density of the object. If a region of space-time has a low enough mass and density, it will not have an event horizon.

4. How does the presence or absence of an event horizon affect the properties of a region of space-time?

The presence or absence of an event horizon can greatly affect the properties of a region of space-time. For example, the presence of an event horizon can lead to black holes, while the absence of an event horizon can allow for the study and observation of the conditions within a region of space-time.

5. Is it possible to create a region of space-time with no event horizon artificially?

It is currently not possible to artificially create a region of space-time with no event horizon. The formation of an event horizon depends on the mass and density of an object, and it is not currently possible to manipulate these properties on a large enough scale to create a region of space-time without an event horizon.

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