3 ms·

How are they remotely mathematically equivalent? The Casimir effect/Lamb shift calculations do not need any input from the cosmological constant's magnitude or

How are they remotely mathematically equivalent? The Casimir effect/Lamb shift calculations do not need any input from the cosmological constant's magnitude or anything equivalent. You can calculate them with naught but the constants you need to fix the form of QED. If you try to go the reverse direction and claim that vacuum fluctuations are what the cosmological constant is really about, like you said you have to explain a massive (orders of magnitude!) discrepancy. Considering that the cosmological constant is nothing more than a magnitude as far as we can tell, a theory about a link that gives the wrong magnitude is completely useless. You can draw a parallel between them conceptually, but that connection is about as solid as the connection between the cosmological constant and any other isotropic scalar field like the Higgs. This is another speculative explanation, but again there is no theory that actually manages to explain the value.

wyager 10y ago
>like you said you have to explain a massive (orders of magnitude!) discrepancy. Yes, I admitted that earlier. This is the tricky part, not that dark energy exists. There are a number of plausible theories as to why the magnitude of dark energy is much lower than expected, but nothing hard and fast yet.
- johncolanduoni 10y ago
  No, the tricky part is where you conclusively link the cosmological constant to vacuum energy with no evidence for and a lot against. There are equally plausible theories that connect dark energy to completely different things like the Higgs field, or just leave them unrelated, so appealing to demonstrations of vacuum fluctuations as evidence of dark energy being "experimentally verified" makes about as much sense as calling string theory "experimentally verified" because it agrees with the QFT/GR in the proper domains. What verified, novel predictions do any of the plausible theories make that makes them the defacto solution? I'd be really curious to know because it doesn't appear that many physicists are aware of this defacto solution.

wyager 10y ago

>like you said you have to explain a massive (orders of magnitude!) discrepancy. Yes, I admitted that earlier. This is the tricky part, not that dark energy exists. There are a number of plausible theories as to why the magnitude of dark energy is much lower than expected, but nothing hard and fast yet.

johncolanduoni 10y ago
No, the tricky part is where you conclusively link the cosmological constant to vacuum energy with no evidence for and a lot against. There are equally plausible theories that connect dark energy to completely different things like the Higgs field, or just leave them unrelated, so appealing to demonstrations of vacuum fluctuations as evidence of dark energy being "experimentally verified" makes about as much sense as calling string theory "experimentally verified" because it agrees with the QFT/GR in the proper domains. What verified, novel predictions do any of the plausible theories make that makes them the defacto solution? I'd be really curious to know because it doesn't appear that many physicists are aware of this defacto solution.