Watch "Can Many Worlds Solve The Measurement Problem?" on YouTube

[Jason Resch]

https://youtu.be/BU8Lg_R2DL0

This is timely.

Jason

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A Postquantum Theory of Classical Gravity?

[John Clark]

In today's physical review X , Jonathan Oppenheim presented a paper where
he claims to have united general relativity and quantum mechanics, he
doesn't change general relativity at all but he does add an additional
probabilistic element to quantum mechanics . He says his theory doesn't
have any internal inconsistencies but determining if it's true will require
future experiments to see if spacetime is continuous or discrete, Oppenheim
thinks it's continuous and thus General Relativity needs no modification,
but quantum mechanics does.

*Abstract: *
By Jonathan Oppenheim

"*The effort to discover a quantum theory of gravity is motivated by the
need to reconcile the incompatibility between quantum theory and general
relativity. Here, we present an alternative approach by constructing a
consistent theory of classical gravity coupled to quantum field theory. The
dynamics is linear in the density matrix, completely positive and trace
preserving, and reduces to Einstein’s theory of general relativity in the
classical limit. Consequently, the dynamics doesn’t suffer from the
pathologies of the semiclassical theory based on expectation values. The
assumption that general relativity is classical necessarily modifies the
dynamical laws of quantum mechanics – the theory must be fundamentally
stochastic in both the metric degrees of freedom and in the quantum matter
fields. This allows it to evade several no-go theorems purporting to forbid
classical-quantum interactions. The measurement postulate of quantum
mechanics is not needed – the interaction of the quantum degrees of freedom
with classical space-time necessarily causes decoherence in the quantum
system. We first derive the general form of classical-quantum dynamics and
consider realisations which have as its limit deterministic classical
Hamiltonian evolution. The formalism is then applied to quantum field
theory interacting with the classical space-time metric. One can view the
classical-quantum theory as fundamental or as an effective theory useful
for computing the back-reaction of quantum fields on geometry. We discuss a
number of open questions from the perspective of both viewpoints.*


*A postquantum theory of classical gravity?
*

  John K ClarkSee what's on my new list at  Extropolis

qmd

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Re: The new quantum chip

[John Clark]

On Mon, Dec 4, 2023 at 6:39 PM 'spudboy...@aol.com' via Everything List <
everything-list@googlegroups.com> wrote:

*> In the last few years, you predicted a revolution, societally, once we
> hit the heights in successfully entangled, quantum operations. Have you
> changed your mind since this prediction? *
>

No my prediction hasn't changed, I think quantum computers will bring on a
revolution, but it will not be the next revolution. A large practical
quantum computer is probably 10 years away and it will change everything,
but in less than half that time conventional computers will change society
more radically than it has ever changed before in the entire history of the
human species. That's why I can't get too hot and bothered about trivial
little things like illegal immigration, the budget deficit, or drag queen
story time. But I'm still concerned about the USA turning fascist and, if
the polls are correct, that could happen in about 13 months. It will be
hard enough getting through the Singularity meat grinder alive, if during
this key moment the most powerful flesh and blood human being in the world
is also an imbecile then all hope is lost.

  John K ClarkSee what's on my new list at  Extropolis

oa1






>
> Apparently IBM has hardwired a new error correcting algorithm into its new
> quantum chip called "Quantum Low-Density Parity Check" (qLDPC), only 288
> physical Qubits are needed (provided the physical error rate is less than
>  0.1%) to produce 12 perfect logical cubits; with older error correction
> codes many thousands of physical Qubits would have been required. The
> difficult part was that for qLDPC to work each physical Qubit had to be
> connected to 6 other Qubits, in older quantum chips there was only a
> connection with two or three.
>
> IBM releases first-ever 1,000-qubit quantum chip
> 
>
>
> Unveiling IBM Quantum System Two
> 
>

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