I am bringing in this question elements from a couple of domains of the physics.
1. It is known that the cosmological constant predicted by the general relativity (GR) is by cca. 40 orders of magnitude smaller than the prediction of the quantum field theory (QFT).
It's on the latter prediction that I place a question mark.
2. In the nuclear theory (NT) and in quantum optics (QO), the spontaneous decay of a nucleus or of an excited atom is explained by the coupling with the vacuum states of the respective emitted particles. In short, the decay Hamiltonian contains three terms: one describing the isolated nucleus, respectively, atom; one describing the vacuum (for particles or for the electromagnetic field; one representing a coupling term. The Hamiltonian of nucleus or of the atom alone, would predict for the bound states perfect stability, the decay would never occur.
3. Quantum entangled states are known as preserving the quantum correlations no matter how far away from one another fly the entangled particles. The condition for this preservation is to ensure that the particles won't be pertubed, condition usually achieved by letting the particles fly in deep vacuum.
The Hamiltonian we write for the entangled particles flying in vacuum, is the free particle Hamiltonian, without the two terms introduced in NT and QO, i.e. the vacuum Hamiltonian for these types of particles, and the coupling. These terms would perturbe the entanglement, perturbation that the experiment doesn't indicate.
Someting is inconsistent here, isn't it?
Sofia
When a particle flies in a vacum, it nevertheless should experience a certain noisy effect from the environment in the form of photons for example and that gradually modifies the original information of its creation. This is called decoherence. To treat this theoretically you of course need interaction or coupling terms. There is in practice a limitation in distance
(coherence length) to show quantum effects.
However I do not see how this pertains to the Cosmological constant problem.
@Juan Weisz,
Where are you? I didn't see a comment from you for a long time.
Now, to physics. The noise from environmnt, as you say, is only if the vacuum is not enough deep, or there is undesired reflection or absorption by apparatuses. But there is no sign of decoherence as I say, i.e. that the Hamiltonian of the entangled particles flying in the free space, shouln't be the free particle Hamiltonian.
The coherence length has no role here, I don't see what you want to say with it. Which limitation in space? Two entangled particles may be let fly away from one another as far as we wish.
The connection with the cosmological constant is as follows: the constant was calculated in two ways, 1) with the tools of the general relativity, 2) from the zero-point energy of the vacuum. It's this zero-point energy that seems to me "abra-cadabra", i.e. in some experiments it has an influence, in other experiments it doesn't. That is not permitted, if this energy exists, it should appear as a perturbance in any experiment. In particular it should decohere entanglements because it should be expressed as two terms added to the free-particle Hamiltonian.
Sofia
actually its been rather hot here, so im half on holidays.
Forgive my scepticism about entangled particles remaining such
forever. The universe is noisy and quantum phenomena is suceptible
to perturbations.
Neither in my mind can I seem to asociate interactions with a zero point energy level. Im missing something.
Or my brain is baked right now.
Regards, juan
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