Collapse Definition and 466 Threads

Consider a ball of dust mass M, Radius R stats from rest and collapses due to gravity. Q. Find total time of collapse. This I am currently working on I believe I can show this using conservation of momentum. Q. Prove that it remains homogeneous Dose anyone have any ideas on this one, I...

Doesn't complete information about a probability distribution presuppose a physically determined wavefunction collapse? How can we have knowledge about statistics of all existent quanta for the wavefunction except by light signals in the first place, whose correspondent reversed process should...

there's something that is annoying me, because I can't find a explanation It's about the classical double slit experiment, where you have two screens, and one of them has 2 narrow slits then you launch a photon against the screens, and if there are no detectors in the slits, you observe an...

Please read this article: http://www.nature.com/news/2004/040712/full/040712-12.html I can't understand, which it says This suggests that black holes do not actually narrow to a singularity at all I can't understand, please explain :redface:

This question is probably pretty silly looking at the complicated discussions going on here, but I'll ask none the less. Why don't Atoms spontaneously collapse? If there is a proton and there is an electron, shouldn't they attract each other and form a neutron? In trying to understand why...

i am a little stuck on this, can someone please put me straight This is from P7 of The Physics of Stars by AC Phillips g(r)=G m(r)/r^2 which states that each mass element at r moves towards the centre with an acceleration g(r). He then goes on to state that the inward velocity...

Does the observational process quantum-->classical ever reverse?

stars are formed from gas clouds, these gas clouds posses potential energy and kinematic energy, they may also exhibit a density contrast, theory tells us that collapse of the gas cloud starts when PE overcomes KE, but i can find no explanation for the trigger to this collapse ,put another...

From what I have gathered, whether or not decoherence has solved the measurement problem is still a matter of debate. But to those who say that it does, my question is: how does it solve it? Does it actually cause the collapse of the wavefunction? These questions are actually pieces of a...

Hate to ask another one of these questions, but I've just read something about the collapse of the wave function that does not seem consistent with other accounts I've read about it. From what I understand, the wave function of a system is collapsed automatically by interaction with another...

I have a question. Suppose we have an electron orbiting around a proton in a Bohr atom. It is accelerating due to centripetal motion yet traveling at v<<c so Newtownian physics applies. Since it is accelerating, it is radiating energy. Assuming we are using larmor's formula for power radiated...

A protostar will begin gravitational collapse only if the total gravitational potential energy exceeds twice the thermal energy. In other words, a gas has to be sufficiently cool and sufficiently dense to collapse. Also, as the protostar collapses about half of the gravitational PE is converted...

I've heard many times that one of the major faults of the classical model of an atom is that it would collapse. In other words, the electrons wouldn't stay orbiting the nucleus for very long before they hit into it. Although I've heard this many times, I don't think I've ever heard the...

The collapse of religions, mass suicides, the collapse of governments? What would the result be if, as I suspect, it [edit to avoid confusion] was generally believed that some highly advanced civilization - one completely beyond our reach or understanding in any technical or intellectual sense...

I assume that some speed limit must exist that limits how often we can measure something - if is exists, perhaps the Plank time unit governs this? Do we know this answer? Does this relate to the speed of quantum computers?

In thought experiments that I have done, I've always thought that there was another universe that is sort of an inverse to ours. It is composed of antimatter (it has "reversed" gravity-a force that repels) and its laws of physics are governed by imaginary numbers (i). If these two universes...