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The Search For Neutrons That Leak Into Our World From Other Universes
KentuckyFC writes: One of the more exciting predictions from "braneworld" theories of high energy physics is that matter can leak out of other universes into our own, and vice versa. The basic idea is that our three-dimensional universe or brane is embedded in a much larger multi-dimensional cosmos. These branes can become coupled so that a quantum particle such as a neutron can exist in a superposition of states in both universes at the same time. When the neutron collides with something, the superposition collapses and the particle must suddenly exist in one brane or the other. That means neutrons from our universe can leak into other branes and then back again. Now physicists are devising an experiment to look for this neutron leakage. They plan to put a well shielded neutron detector next to a shielded nuclear reactor that produces neutrons at a research facility in France. All this shielding means the detector should not see any neutrons from inside the reactor. However, if the neutrons are leaking into another brane and then back into our world, they can bypass this shielding and trigger the detector. The team has not yet set a date for the experiment but the discovery of neutrons (or anything else) leaking into our universe would be huge.
Would this help explain quantum tunneling?
The idea is to create so many they couldn't help to jump back and forth. To (hopefully) leak into another brane and (hopefully) leak back.
If they just sit in the middle of nowhere, it's a hope that an abnormally large source from another brane just happens to emit in that particular spot at the right time. In other words, beyond improbable.
XML is like violence. If it doesn't solve the problem, use more.
OK, so we have multiple cosmi (space-time continua) embedded in a higher dimensional universe. I'm totally down with that and have written an entire SF novel based on the premise. Those cosmi (as the plural of cosmos) have a coupling. I'm good with that. But that means that "neighboring" cosmi will exist in a coherent bundle, and one will have to get quite distant from "this" brane to find a brane with substantial drift in its general mass distribution.
This is simple statistical mechanics, by the way -- if most brane-to-brane transitions occur in places where there is chuck of mass in one cosmos and none in another cosmos, there will be steady diffusion from the high mass concentration to the low one. This would lead to egregious and painful violation of mass-energy conservation as my foot in this cosmos diffuses into a vacuum in many, many others, because after all, the mass density of any cosmos at all is nearly zero with a hard, hard vacuum nearly everywhere.
This is overwhelming evidence that this sort of brane to brane, cosmos to cosmos transition does NOT happen in a universe in which the cosmi are equidistant and randomly organized. The only way that those transitions are possible at all is if there is a metric in the higher dimensional universe and if neighboring cosmi have ALMOST identical mass distributions and if transitions are only likely as pair exchanges between neighboring cosmi (note the requirement for pair exchanges is also a rather hard one or else one would observe a cumulative violation of conservation of mass in random-walk style that would be impossible to miss and that people have looked for, unless the transitions were VERY unlikely, or became very unlikely as a function of the intercosmos metric separation to increasingly different cosmi.
Note well that these constraints mean that no matter what, they aren't going to "bypass" a shield with a neutron flux, because there are going to be no nearby cosmi/branes in which the shield does not exist.
Note well in addition the response to those who suggest that this might be a way of viewing tunnelling. It is indeed -- the alternative cosmi are one of the POSSIBLE (I don't say plausible) interpretations of path integral formulations of quantum mechanics, integrated out. But in this case you STILL won't get tunneling through a barrier centimeters thick.
So this is a pointless experiment. One might as well just look for egregious violations of mass-energy conservation in everyday experiments, because if there is any substantive probability of mass energy departing our own spacetime cosmos and appearing in another "nearby" one, it would happen all the time and all mass concentrations would diffuse out into a multicosmo heat death.
Gravitation is an excellent possibility as the coupling between branes/cosmi -- one would guess that the "dimpling" of one spacetime dimples all of the neighboring ones on all sides (however many "sides" there are:-). The dimples probably don't have to precisely correspond, but they are likely to have to approximately correspond to minimize almost any sort of coupling across the sheets that permits a transition to occur in the first place.
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Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
Well, we don't really have any reason to expect alternate universes to exist at all, except that the theories don't preclude them.
The real problem is that we have some really huge gaping holes in established theory*, places that we *know* our understanding is flawed, and all the "patches" we've dreamed up are so outlandish that we need even more outlandish experiments to test them, where we've even managed to dream up potential experiments at all.
* for example - General Relativity requires that the base energy of empty space be exactly zero, while Quantum Mechanics requires that it have a definite non-zero value. (the so-called vacuum energy field) Both cannot be the case, so clearly one or both theories must be flawed.
--- Most topics have many sides worth arguing, allow me to take one opposite you.