Physicists also do not like that pilot wave theory is non-local.
A more severe problem is that it is not relativistic. More precisely, as John Bell said of a stochastic version, “As with relativity before Einstein, there is a preferred frame in the formulation of the theory, but it is experimentally indistinguishable”. You need some notion of absolute simultaneity, in order to write down the equations of motion.
Bohmian mechanics (to use another name for this dynamical framework) has analogous problems with some other symmetries. For an example concerning “lapse” and “shift” functions in general relativity, see this old paper. The situation is at least as bad in gauge theories, such as those that describe the strong and electroweak forces.
There is no ontological interpretation of quantum theory, known to me, that is free of problems. The simplest attitude to have is that quantum mechanics works empirically, that it is ontologically incomplete, and that we don’t know the true ontology.
It would be tiresome to go through all the proposals listed in that article, identifying how they work, the resultant limitations, and then speculating whether they might nonetheless help us understand reality one day. Or at least, I think I would save that kind of analytical effort, for an audience of physicists interested in ontology.
But let me just discuss one example. The proposal discussed in the most detail, is due to Dürr et al. The article straight out says that they rely on the existence of a “preferred foliation” of spacetime. That means that to define their “relativistic” Bohmian mechanics, they still need a particular decomposition of spacetime into a stack of spacelike hypersurfaces. Their trick is to then say, well, we don’t need to use a coordinate system in which those hypersurfaces are all “t = constant”. We can do a relativistic boost, and switch to a new coordinate system with a new time coordinate, in which those hypersurfaces are tilted with respect to the time axis.
That’s formally true, but nonetheless, their pilot wave and their equations of motion are only defined with respect to one specific foliation, which de facto defines a notion of absolute simultaneity.
The point is that all these “extensions to relativity” involve some kind of trick, or they only work in an artificially narrow setting, or they meander off in some eccentric direction. There is certainly no relativisitc Bohmian mechanics known, that can deal with all the known phenomena of field theory, like pair creation and gauge invariance.
A more severe problem is that it is not relativistic. More precisely, as John Bell said of a stochastic version, “As with relativity before Einstein, there is a preferred frame in the formulation of the theory, but it is experimentally indistinguishable”. You need some notion of absolute simultaneity, in order to write down the equations of motion.
Bohmian mechanics (to use another name for this dynamical framework) has analogous problems with some other symmetries. For an example concerning “lapse” and “shift” functions in general relativity, see this old paper. The situation is at least as bad in gauge theories, such as those that describe the strong and electroweak forces.
There is no ontological interpretation of quantum theory, known to me, that is free of problems. The simplest attitude to have is that quantum mechanics works empirically, that it is ontologically incomplete, and that we don’t know the true ontology.
There are extensions to relativity, just like the other interpretations.
It would be tiresome to go through all the proposals listed in that article, identifying how they work, the resultant limitations, and then speculating whether they might nonetheless help us understand reality one day. Or at least, I think I would save that kind of analytical effort, for an audience of physicists interested in ontology.
But let me just discuss one example. The proposal discussed in the most detail, is due to Dürr et al. The article straight out says that they rely on the existence of a “preferred foliation” of spacetime. That means that to define their “relativistic” Bohmian mechanics, they still need a particular decomposition of spacetime into a stack of spacelike hypersurfaces. Their trick is to then say, well, we don’t need to use a coordinate system in which those hypersurfaces are all “t = constant”. We can do a relativistic boost, and switch to a new coordinate system with a new time coordinate, in which those hypersurfaces are tilted with respect to the time axis.
That’s formally true, but nonetheless, their pilot wave and their equations of motion are only defined with respect to one specific foliation, which de facto defines a notion of absolute simultaneity.
The point is that all these “extensions to relativity” involve some kind of trick, or they only work in an artificially narrow setting, or they meander off in some eccentric direction. There is certainly no relativisitc Bohmian mechanics known, that can deal with all the known phenomena of field theory, like pair creation and gauge invariance.