On 04-10-2019 23:09, 'Brent Meeker' via Everything List wrote:
On 10/3/2019 11:49 PM, smitra wrote:
On 04-10-2019 00:51, Bruce Kellett wrote:
On Fri, Oct 4, 2019 at 8:24 AM Lawrence Crowell
<[email protected]> wrote:
This really is a well enough explained question.
LC
Energy conservation is not violated because to correctly sum up
the total energy, you have to weigh the energy in each branch with
the probability of that branch. This works the way it always works
in quantum mechanics. There is nothing new going on here, nothing
controversial, and nothing interesting.
http://backreaction.blogspot.com/2019/09/the-trouble-with-many-worlds.html?showComment=1569889923590#c1373154727748966620
The trouble I see with the explanation Sabine gives, which is
probably
the most common response to this question, is that it dilutes the
energy in each branch according to the Born weight. Given that there
a
zillions of branchings per second throughout the visible universe,
the
energy rapidly is weighted away to zero in all branches. This does
not
make much sense. Besides, that is not what one does in ordinary
quantum mechanics -- I have no idea what Sabine is referring to here.
The only solution for MWI, it seems to me, is that the energy is
simply conserved in each branch, and not conserved over branching
interactions. How would you ever test this, anyway? Block universe
ideas do not actually help here. And appeals to energy non
conservation in non-stationary universes are beside the point --
Quantum mechanics is not GR.
The block universe point of view makes this a non-issue. You get into
trouble by assuming something like presentalism, like a hidden
assumption about the energy of one instant being transferred to the
next instant.
But that's what energy conservation is.
Energy conservation is also consistent with block time, so energy
conservation alone does not single out the interpretation of itself as a
physical transfer of energy from one instant to another instant. One can
choose to interpret it like that, but one can for example just as well
assume a multiverse of all time snaps of all possible universes with
different energy contents, the laws of physics are then nothing more
than a mathematical statement that tells you that universe X and
universe Y have the same information content giving a prescription of
how to compute things in Y given the state of X. Nothing is then
actually physically transferred from X to Y.
If you drop this assumption and simply take thew block universe point
of view where all the instances already exist out there, then there is
no problem to begin with.
Do all the branches then exist equally? in which case you've
abandoned energy conservation and now you need to explain why it
appears to be conserved on every branch.
If under a time evolution a state X becomes a superposition of states
Y1, Y2, ..., Yn, then the block time interpretation of that is that Y1,
Y2,....., Yn and X are all different universes and that the information
in X can be retrieved not from a single universe Y_i, but it's
distributed over the different universes Y1,...Yn. If all the Y_n have
well defined and equal energies then these energies are equal to that of
state X. The information about the energy in state X is then present in
each state Y_k separately.
Saibal
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/everything-list/a5f7067e5416ed40921b1c46036a7f31%40zonnet.nl.
