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lulmerchant | 8 years ago
QED works quite well in most cases, but only if you don’t look too closely, and only if you ignore one of the fundamental forces. QED offers no explaination for gravity, which even non-physicists know exists.
What is gravity? What is a particle? What is space? These are all quite basic questions that were not even close to having complete answers for. QED provides a “good enough” explaination for how particles and space work, just as relativity gives a “good enough” explaination of gravity. But any physicist who’s being intellectually honest knows that we only have a rudimentary understanding of these concepts. The wave function is just an excellent tool we use to smooth out our lack of understanding. Your comment is a perfect example of the arrogance that pervades the scientific community, and the inability to acknowledge the limits of our own understanding. Which I think only inhibits the wider community’s ability to communicate effectively with the general public.
raattgift|8 years ago
It does; gravitation in perturbative QED on time-dependent curved backgrounds has exactly the same explanation as General Relativity. [1] This generalizes very well. [2]
One can look at it the other direction too: General Relativity guarantees flat spacetime in the neighbourhood of every point on the manifold with signature 1,3 or 3,1. As long as the radius of curvature is large compared to the system under study there is no trouble at all (QED systems are usually pretty tiny, so you're good down to and through astrophysical black hole apparent horizons). This is implicit in laboratory tests of QED.
> But any physicist who’s being intellectually honest knows that we only have a rudimentary understanding of these concepts
Everyone should be honest about how much she or he really knows, and how much he or she can judge how much someone else really knows.
"The first principle is that you must not fool yourself — and you are the easiest person to fool" -- Feynman
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[1] [BirrellDavies] N.D. Birrell and P.C.W. Davies, Quantum fields in curved space, Cambridge University Press, Cambridge U.K. (1982).
[2] [BGZV] A.O. Barvinsky, Yu.V. Gusev, V.V. Zhytnikov, and G.A. Vilkovisky, SPIRES-HEP:Print-93-0274(Manitoba), (1993). https://arxiv.org/abs/0911.1168
dbasedweeb|8 years ago
Fundamental = bedrock
QED works to the best ability of any test, down to one part in ten billion, so looking very close indeed. Then in order...
What is gravity? The geometry of spacetime.
What is a particle? A localized excitation of a field.
It may be that you don’t like or understand the answers, but they exist and allow people to make precise predictions, build machines that work based on said principles. Maybe you’re confusing scientific answers with philosophical ones?
lulmerchant|8 years ago
Adjective
1. forming an essential foundation or starting point; fundamental.
Your answers to those questions are either deliberately over-simplifying to avoid the question, or you don’t understand QED yourself. Your definition of a particle describes a possible outcome of a measurement, and ignores the existence of a wave function. Your description of gravity cannot be created in QED. You have provided no explanation of space whatsoever, which is so woefully unexplained by quantum mechanics, that it is referred to as the ‘vacuum catastrophe’.
Anybody who investigates these concepts can see that our understanding of them is woefully incomplete. However scientists tend to have a very hard time acknowledging these limits of our understanding, and will often respond to such acknowledgements with thinly veiled contempt. Just as you have done by trying to undermine my opinion on them, rather than responding to what I have said. I think that by failing to acknowledge the limits of scientific understanding, maybe you are confusing science with religion?