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

  • Thread starter Thread starter San K
  • Start date Start date
  • Tags Tags
    Space-time
San K
Messages
905
Reaction score
1
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
 
Last edited:
Physics news on Phys.org
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.
 
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.
 
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
 
There will always be virtual photons.
The problem is that a "true vacuum" is too specific and would violate Heisenberg Uncertainty.
 
Not an expert in QM. AFAIK, Schrödinger's equation is quite different from the classical wave equation. The former is an equation for the dynamics of the state of a (quantum?) system, the latter is an equation for the dynamics of a (classical) degree of freedom. As a matter of fact, Schrödinger's equation is first order in time derivatives, while the classical wave equation is second order. But, AFAIK, Schrödinger's equation is a wave equation; only its interpretation makes it non-classical...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
Is it possible, and fruitful, to use certain conceptual and technical tools from effective field theory (coarse-graining/integrating-out, power-counting, matching, RG) to think about the relationship between the fundamental (quantum) and the emergent (classical), both to account for the quasi-autonomy of the classical level and to quantify residual quantum corrections? By “emergent,” I mean the following: after integrating out fast/irrelevant quantum degrees of freedom (high-energy modes...
Back
Top