On 10/28/2022 9:16 AM, smitra wrote:
On 26-10-2022 01:40, Bruce Kellett wrote:
On Wed, Oct 26, 2022 at 10:15 AM smitra <[email protected]> wrote:
On 26-10-2022 00:14, Bruce Kellett wrote:
There is no such thing as irreversible decoherence in unitary QM.
Now,
you and Brent have invoked the expansion of the universe in past
discussions to argue that fundamentally irreversible phenomena do
exist.
However this reasoning is flawed, because you then assume a
semi-classical model where the expansion of the universe is
described in
a classical way. If QM is fundamental, then the entire state of the
universe, including the space-time geometry is part of that quantum
description. You then have a wavefunctional that assigns a complex
amplitude to the entire state of the universe that includes al the
fields of all particles and also the space-time geometry.
Thing is that the laws of physics are what they are. You cannot
demand
that you require measurement results to be truly permanent and that
they
therefore arise due to irreversible processes. Whether that's the
case
or not is determined by the laws of physics, not by us.
The laws of physics tell us that measurements are irreversible.
Unitary evolution is universal only in your imagination. Many Worlds
is an interpretation, not an established fact.
Bruce
The laws of physics as we know them today, rule out the existence of
any physical process that is fundamentally irreversible.
What does that mean for radiation to infinity? Do you just rule it out
as "not fundamental" since it depends on a boundary condition at
infinity? Yet it is still physics and universal.
Brent
So, measurements cannot be irreversible if the known laws of physics
are correct. If you disagree then it's up to you to point to just a
single example of such a process and write up an article that proves
your point and get that published in a per reviewed journal.
Simply saying that QM as traditionally formulated considers
measurement as a special process that os irreversible, doesn't cut it,
because measurement is then not treated in terms of the fundamental
dynamics of the theory, it is put in in an ad hoc way.
Saibal
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