2,985 reputation
1425
bio website staff.science.uu.nl/~hooft101
location Utrecht, Netherlands
age
visits member for 3 years
seen Aug 12 at 7:35

Theoretical physicist, Utrecht University.

University Professor. Elementary particle physics, quantum gravity, black holes, quantum mechanics.

Won some prizes (such as the nobel prize 1999), but please don't hold that against me.


May
10
awarded  Nice Answer
Mar
25
awarded  Favorite Question
Mar
1
comment How does Bell's theorem rule out the possibility of local hidden variables?
@Gugg: I just don't agree with the Zeilinger quote. Determinism indeed implies that the experimenter's decisions, and questions, are generated by physical forces themselves, so his attitude would dismiss determinism categorically, and I am not ready to go that far. And my bottom line remains to be a simple one: I now have models telling me what might happen, and what they say does not disturb me. Important: I still keep causality intact.
Mar
1
comment How does Bell's theorem rule out the possibility of local hidden variables?
@user7348 : Non-locality would generate serious trouble with special relativity and causality. And I don't need it. That's why I don't introduce it. Non-local correlations is not the same as non-locality in the equations of motion. In QFT, the equations of motion are local but the vacuum-correlations are not. This is because the vacuum is a special solution of the e.o.m.
Feb
27
revised How does Bell's theorem rule out the possibility of local hidden variables?
deleted 4 characters in body
Feb
27
answered How does Bell's theorem rule out the possibility of local hidden variables?
Feb
27
comment What are the 't Hooft papers about classical models underlying QM?
except that it raises the suspicion that what's really happening in this world might be just these ontological states, and the rest is due to our limited understanding, somewhat contaminated with some sort of religious feeling that God likes to superimpose. So, the answer to @Motl's objection is that it's our equations used to describe observed reality that allow for superpositions, not reality itself. I thought that this statement would be trivial and unimportant, but if not understanding it causes someone to reject the models first-hand, apparently the statement is important after all.
Feb
27
comment What are the 't Hooft papers about classical models underlying QM?
Our theory is now that physicists describing the real world have no way of knowing whether they are describing an ontological event, or just any other solution of their equations (except when it's about cats, where we think we DO know!). The simple reason for this is that Schroedinger's equation is linear. We keep that property throughout. But now I add something new: a true, ontological state should, some way or other, evolve to become again a true, ontological state. That's just a constraint on the set of Schroedinger's equations that we impose. What's wrong with that? Nothing of course,
Feb
27
comment What are the 't Hooft papers about classical models underlying QM?
There's this little point that @Motl failed to grasp about these models: It's the "ontological, true" events described here that are such that any superposition of such events is NOT an ontological event. That's just like cats: the dead cat is ontological, the live one is, but any superposition of the two isn't, or at least, that's the case in our models. Now the superposition of the two cats DOES obey Schroedinger's equation. What I have done is take all "ontological" states of a system and look at the equations they obey. Now superpositions of ontological states also obey the equations.
Dec
27
awarded  Good Answer
Nov
8
comment Will Determinism be ever possible?
sigoldberg1 and Seamus's remarks about Laplace apply if the world is described by real numbers. The problem with real numbers is that they each require infinite sets of digits. If you can't control the millionth digit you will have indeterminism. This problem would not arise if we would have theories based only on integers, or even better, bounded integers.
Nov
7
comment Will Determinism be ever possible?
Indeed, I should have stated more clearly that I mean local reality, and that this should be interpreted in a completely classical sense. But, as you say, this "reality" is not about particles with position, momentum, etc. My minority view is that there is a loophole in the arguments usually employed against local reality.
Nov
4
awarded  Citizen Patrol
Nov
4
answered Will Determinism be ever possible?
Nov
1
comment Is flying really easier on smaller scales?
Apologies to AlanSE, my comments and questions were to be directed to @miceterminator.
Nov
1
revised Is flying really easier on smaller scales?
added 6 characters in body
Oct
30
comment Is flying really easier on smaller scales?
But this is what I read on my screen, signed by your name. If you didn't mean $\sqrt{\text{diameter}}$, then what are you trying to say?
Oct
28
comment Is flying really easier on smaller scales?
@AlanSE Please explain why you write $\sqrt{\text{diameter}}$ where I would have expected $\text{diameter}^2$, assuming that strength of muscle tissue is more or less size independent. Of course, the energy produced by a muscle scales with its volume, times frequency.
Oct
28
revised Is flying really easier on smaller scales?
added 2 characters in body
Oct
27
answered Is flying really easier on smaller scales?