2
$\begingroup$

Since macroscopic objects have more particle like nature and they are always being observed (interact) with their surrounding, does MWI also applies here and if yes then what is its significance. Is it possible that in different worlds I have different life- like President in one of them. Also I read somewhere that in our world matter is preferred over antimatter during the beginning of the Universe and there must be another parallel Universe in which antimatter is preferred over matter. Does this mean that really another Universe exists?

$\endgroup$
1
  • 1
    $\begingroup$ Let's face it, quantum mechanics is weird and the MWI shows just how weird it can get. If the MWI were true, then the answer to all your questions would be yes. Since no one has yet proposed an interpretation of quantum mechanics that is both logically and philosophically acceptable, the answer must be "who knows." $\endgroup$ Nov 14 '16 at 16:56
2
$\begingroup$

Since macroscopic objects have more particle like nature and they are always being observed (interact) with their surrounding, does MWI also applies here and if yes then what is its significance.

In the many worlds interpretation, interactions that record information about a system prevent interference between different versions of a system. Such interactions include measurements. This effect is called decoherence, see

https://arxiv.org/abs/1212.3245.

There is no collapse. Multiple versions of the system continue to exist after the measurement, but they don't interact with you so you can't see them.

All of the universes in the multiverse obey the laws of physics. It may be the case that in some other universe there is somebody who resembles you in many respects and is president. This seems compatible with the laws of physics as far as I know. It is conceivable that there is an anti-matter universe, but I don't know the relevant laws of physics well enough to be able to tell.

$\endgroup$
1
$\begingroup$

The MWI is what you get when you assume that the time dependent Schrödinger equation applies to all systems, no matter how large. This means that wavefunction collapse after a measurement is only an effective description, the exact description involves a superposition where the observer exists in different states experiencing different outcomes, the observer is then entangled with the system. Such a superposition cannot in practice be distinguished from a situation where only one outcome is realized.

$\endgroup$
4
  • $\begingroup$ But my question is that wave function of macroscopic objects constantly collapse and that means we are living only one of our possible infinite number of fates. Can we decide somehow our fate by this? $\endgroup$ Nov 15 '16 at 8:33
  • $\begingroup$ @PrashantSingh This collapse is only an "effective collapse", due to entanglement with environmental degrees of freedom. This process is known as decoherence, see alanf's answer for more details. You may also find this article interesting to read: arxiv.org/abs/1212.0953 $\endgroup$ Nov 15 '16 at 20:10
  • 1
    $\begingroup$ Another thing here is that your personal identity is in principle defined by all the information you have including the particular measurement outcome. So, the different possible MWI outcomes can be interpreted as giving rise to (slightly) different persons. So, the idea that "you" are "living one particular fate" is misleading, because any particular "you" only exists at one particular moment in time. Different "you"'s exist, and arguably different persons here on Earth can be interpreted as such different versions of you who split off from you a long time ago. $\endgroup$ Nov 15 '16 at 20:17
  • 1
    $\begingroup$ E.g., when you were born, you probably could not see the difference between being born at the date that your birth certificate now shows, or at some totally different date, say in the 19th century. This means that your observations directly after leaving your mothers womb, would not have located you in a very narrow sector of the multiverse, only after new observations would you have split away from your copies in the 19th and 22nd centuries. So, there are billions of people who were born in different times and places who were your copies who branched away from your branch a long time ago. $\endgroup$ Nov 15 '16 at 20:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.