When you say the word 'quantum', you will soon hear the word 'observation'.Thats it! Quantum mechanics(QM) is popular because of 'yap yap observer creats the world yep yep'and nothing much more! It is often said that QM confirms eastern mysticism where the world we see is a 'dream' all created by the power of mind and its 'observation'. But do QM realy teaches such things? Did physicists( or eastern mystics for this matter) somehow observed the world without observing it to check how it is when it is not being observed? Why don't they observe vacuum and creat money when they need them? Alright you have guessed well, it is nothing of the sort. If you are among those who have in mind only the 'yap yap quantum yep yep observations' then welcome to some lessons in QM.
If you have searched further you might have seen how ridiculous physicists behave when handling this matter. They say that when a quantum system is yet to be observed, it is impossibly in a superposition of states such as 'both a life and dead' and that only after observation do nature make up its mind as to whether the cat is dead or alife! Then they conveniently deny latter that this is in fact what they said! This is not a surprise. Like a religion, QM has myriads of sects and cults. So you must be care full when reading about QM or otherwise you will get hopelessly confused. Ironically the most confused guys are the physicists themselves. They are the worst victims of their own vodka.
At the heart of confusion in physics is their habit of not completely abandoning 'wrong' theories that can make good approximations of observed world.You will hear of 'relativistic QM' vs 'non relativistic QM' as if these two theories can coexist in the same universe. In reality though, these theories are mutually incompartible. In Quantum Field Theory (QFT), particles must be seen as 'point size' because of relativistic stipulations. But the 'collapse of wavefunction' is said to 'connect QM maths with observations'. This is ironical since point sized particles, whatever that mean, cannot possibly be observed. So what are these non point like entities we observe and term them 'particles', e.g in a bubble chamber? At some point, you will be forced to say that we actually observe tiny wave packets. So the 'collaps' don't happen (since the collapsed state is the zero sized, unobservable particle ). This contradict the earlier picture of QM where the particles are 'created' from waves via 'observation'. Despite this, physicist teach QM to laymen ( and sometimes to thenselves) as if QFT don't introduce any changes in the concept of particle because of the mis perception that'QM is also correct as a non-relativistic theiry'. The world is either relativistic or not, never both. Physicists cannot be allowed to switch back and fort to fully cover their asses.
So ridiculous enough, we are left wondering if quantum state actually 'collapses' upon observation yet this was all what QM was trying to teach! The problem gets compounded this way: 'observation' is (perhaps erroneously) thought to be a classic event. This means that observation necessarily involves myriads of particles, forming your brain. But the particles themselves are supposed to be the quantum. So if we think that the classic world is composed of collapsed quantum particles, then we need an ensemble of collapsed particles( the brain ), to collapse the quantum particles (via observations). We have an egg-chicken paradox.
There are only two resolutions to the paradox. One is to say that observations don't involve particles at all. This remove consciousness away from the brain because the brain is thought to be obviously made from particles. This resolution is of course untenable to many physicists who tends to be 'materialists'. You can begin to now understand why they opt to hopeless confusion like denying what they had been saying all along! The other option is to deny that the brain and all classic objects are composed of collapsed quantum particles. Rather, they might be composed of decoherent quantum waves. This create another problem. Quantum waves are not supposed to represent real things in of themselves. If they did so, they will be classic waves,not quantum waves.So quantum guys will have really not discovered anything new under the Sun! Furthermore, such classic waves requires an observable aether, an idea they have been ridiculing for a century. So they really have no way out! This is why it is called 'measurement problem'. As usual, when they discover what challenges their beliefs, they don't call it that: discovery. The call it a 'problem'. But as long as the beliefs remain, it will forever remain a problem!
I do away with quantum waves and use classic waves that requires a real medium. This waves take particles as if the particles are surfing. So it is like the so called 'pilot wave interpretation'. Though pilot wave is the most straight foward interprataton, it isn't popular because it alongside quantum non-locality shows that Einstein's relativity isn't as correct as it is preached. Infact this was the reason Einstein did not like QM. Being a realist, ideas like 'pilot-wave' only came to his mind. The collapse doesn't creat particles. Particles are always there. The collapse confines the location of the otherwise incessantly darting particle into a tiny dot via a decoherence. As you think carefully,such a confinement must involve 'information' traveling faster than light.
So why don't I care about the supposedly proven Einstein's theory? The answer is that we don't really prove science theories. This wisdom have long been lost. In science, there are always many ways of explaining a phenomenon. The one in books are far from being the only one. What decides theories are often not the neat experiments but the more murky criteria termed 'Occam's Razor'.The usage of this criteria is particularly notorious in QM and relativity. For instance why should we really say that a clock is slowed down by 'slowing of time in its vicinity'? Isn't it easy to say that it is slowed by some invisible particles it collide with as it rush through them? Sure it is, but this destroys Einstein's interpretation of 'relativity of clock measurement'. Specifically, no experiment ever done is actually incompatible with the idea that time is absolute. It is only incompatible with the idea that our clocks measures such absolute 'Tickings' . So we really have no reason to think that even a wave in aether don't don't share the same instance with an arbitrarily distant particle. There is no relativity of the simultaneity itself. What is relative is the events observed at that absolute moment shared by all.