Even Physicists Don’t Understand Quantum Mechanics

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Even Physicists Don’t Understand Quantum Mechanics

Postby socrat44 on September 7th, 2019, 1:20 pm 

Even Physicists Don’t Understand Quantum Mechanics
Worse, they don’t seem to want to understand it.
By Sean Carroll
Dr. Carroll is a physicist.
Sept. 7, 2019
====
Physicists don't understand their own theory
any better than a typical smartphone user
understands what’s going on inside the device.
#
There are two problems.
One is the “measurement problem” of quantum theory.
The other problem is ''wave functions''
#
If nobody understands quantum mechanics,
nobody understands the universe.
. . . . .
Few modern physics departments have researchers
working to understand the foundations of quantum theory.
. . .
Physicists brought up in the modern system will
look into your eyes and explain with all sincerity that
they’re not really interested in understanding how
nature really works; they just want to successfully
predict the outcomes of experiments
. . .
In the 1950s the physicist David Bohm, egged on
by Einstein, proposed an ingenious way of augmenting
traditional quantum theory in order to solve the
measurement problem.
Werner Heisenberg, one of the pioneers of quantum
mechanics, responded by labeling the theory
“a superfluous ideological superstructure,” and
Bohm’s former mentor Robert Oppenheimer huffed,
“If we cannot disprove Bohm, then we must agree to ignore him.”
. . . .
A more recent solution to the measurement problem, proposed
by the physicists Giancarlo Ghirardi, Alberto Rimini and
Tulio Weber, is unknown to most physicists.
. . . .
But they have been neglected by most scientists.
For years, the leading journal in physics had an explicit
policy that papers on the foundations of quantum mechanics
were to be rejected out of hand.
. . . .
The situation might be changing, albeit gradually.
. . .
It’s hard to make progress when the data just keep
confirming the theories we have, rather than pointing
toward new ones.
. . . .
https://www.nytimes.com/2019/09/07/opin ... ysics.html
====
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Re: Blurred Vision

Postby Faradave on September 10th, 2019, 1:20 pm 

socrat44 wrote:There are two problems. One is the “measurement problem” of quantum theory.The other problem is ''wave functions'' - Caroll

More fundamentally, one must consider the problem of viewing the 4D perspective of physical phenomena through the distorted lens of spacetime (both in Relativity and Feynman diagrams). This obscures many otherwise quite evident relations. Pity.

"… the best we can do for figures in Minkowski space is to map them onto Euclidean space, as did Mercator with his flat map of the curved surface of the earth. Such maps necessarily distort metric relations and one has to compensate for this distortion." – Rindler p.90

Fortunately, we can compensate with simple, Euclidean interval-time coordinates.
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Re: Blurred Vision

Postby socrat44 on September 11th, 2019, 3:14 am 

Faradave » September 10th, 2019, 1:20 pm wrote:
socrat44 wrote:There are two problems. One is the “measurement problem” of quantum theory.The other problem is ''wave functions'' - Caroll

More fundamentally, one must consider the problem of viewing
the 4D perspective of physical phenomena through the distorted
lens of spacetime (both in Relativity and Feynman diagrams).
This obscures many otherwise quite evident relations. Pity.

"… the best we can do for figures in Minkowski space is to map them onto Euclidean space, as did Mercator with his flat map of the curved surface of the earth. Such maps necessarily distort metric relations and one has to compensate for this distortion." – Rindler p.90

Fortunately, we can compensate with simple, Euclidean interval-time coordinates.


If I understand you correct . . .
. . . you see another problem in Minkowski spacetime
and you try to figure it out by . . . .
''Euclidean space'' + ''Euclidean interval-time coordinates.'' . . .
. . . that is actually a Pseudo- Euclidean space . . . ?
=====
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Re: 4D Geometry

Postby Faradave on September 11th, 2019, 4:26 pm 

socrat44 wrote:you try to figure it out by... ''Euclidean interval-time coordinates.''...that is actually a Pseudo- Euclidean space . . . ?

Actually, it is conventional spacetime which is pseudo-Euclidean.

"A very important pseudo-Euclidean space is Minkowski space, which is the mathematical setting in which Albert Einstein's theory of special relativity is formulated. For Minkowski space,..."
as indicated by the minus sign in the interval (∆d) equation: (∆d)² = (∆r)² (∆t)²,
where any spatial radius (r) is given by r = √((∆x)² + (∆y)² + (∆z)²).

By contrast, interval-time avoids the minus sign, yielding a Pythagorean relation which applies exclusively to an underlying Euclidean geometry. This is depicted with orthogonal coordinates (one for each dimension).
(∆r)² = (∆d)² + (∆t)².

What's more, there's nothing "pseudo" about interval coordinates. While space is relative, intervals are invariant, agreed by all inertial observers. Invariance is the most "real" quality in Relativity.

So, where do interval-time coordinates physically apply? Everywhere! Extrapolate the Big Bang (BB) to a single 4D event, central to the balloon analogy of the expanding cosmos. This implies a curved-space, radial-time model, with a 4D temporal field emanating out from the BB. Space is an enclosing 3-sphere at any radius (i.e. at any cosmic age). Here's a diagram from Sean Carroll's Time.

Image
Similar to a field from electric charge, Carroll depicts time as a 4-field emanating from the BB. Blue arcs (added) represent spatial simultaneities t1 (now) and future t2 indicating expansion of the cosmos with age. Space is the 3-sphere enclosing the temporal 4-field at any radius (age of the cosmos).

The same thing shown another way:
Image
Left: A temporal 4-field about a central, Big Bang event (BB) is enclosed at any radius by a spatial 3-sphere (a simultaneity) at rest with respect to the BB (and cosmic background). Center: From any event (p), interval-time coordinates correspond to vmax and v0 respectively. Being independent of time, vmax is non-aging. vx is non-traversable, as it violates fundamentally unidirectional time. (But this shortest possible connection between p & q, may still serve as a simultaneous correlation reference for entangled particles.)
Right: In the rest frame of v1, the size of the cosmos is contracted in the direction of motion, yet vmax remains tangent to spatial simultaneity t1 (all space “now”). Thus, c is invariant.


Aging is maximal at rest (along a timeline) and is avoided altogether at speed c, orthogonal to time. Thus, limit c defines a tangent 3-plane at every location on a spatial 3-sphere.
Rather than merely measure, describe or postulate speed limit c (as physics is now resigned), interval-time coordinates explain it:

c is finite because time is fundamentally unidirectional, enforcing the tangent limit
c is universal because it relates to the underlying structure of the universe (anywhere on a 3-sphere).
c is constant because tangent planes apply to all 3-sphere sizes (i.e. every cosmic age).
c is invariant because tangent planes persist even as spatial curvature increases in the direction of motion with respect to the cosmos.
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edit page is wonky toady and won't give me control of this duplicate image
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Re: Even Physicists Don’t Understand Quantum Mechanics

Postby socrat44 on September 12th, 2019, 4:11 am 

Thank you, Faradave
It seems, i understood:
Minkowski spacetime is a Pseudo- Euclidean space
that is proved by ''Extrapolate the Big Bang'' + ''a Pythagorean relation''
====
P.S.
Bye bye space-time: is it time to free physics from Einstein’s legacy?
Einstein’s framework for the universe, space-time,
is at odds with quantum theory. Overcoming this clash
and others is vital to unravelling the true nature of the cosmos
11 September 2019

https://www.newscientist.com/article/mg ... ns-legacy/
===
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Re: Time to Recionsider Space

Postby Faradave on September 12th, 2019, 7:52 am 

You're welcome.

I don't blame Einstein for spacetime as much as Minkowski.

"Indeed, Einstein himself was not sympathetic to this idea when he first encountered it. The idea of space-time was not, in fact, Einstein’s…It was …Hermann Minkowski …in 1908" - R. Penrose (in preface p.xv)

After initial reluctance, Einstein adopted spacetime diagrams, upon realizing wide acceptance among his contemporaries. They needed something familiar to aid understanding then outlandish findings or Special Relativity. I think Einstein would have delighted in interval-time coordinates, seeing they more elegantly explain the photoelectric effect by direct interval contact (without a "photon" intermediary).

The math works either way but spacetime maps distort interval contact, making it appear as separation.
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What is the quantum measurement problem?

Postby socrat44 on October 22nd, 2019, 8:40 pm 

Tuesday, October 22, 2019
What is the quantum measurement problem?
---
Quantum mechanics tells us that matter is not made of particles.
It is made of elementary constituents that are often called particles,
but are really described by wave-functions.
A wave-function a mathematical object which is neither a particle nor a wave,
but it can have properties of both.

The curious thing about the wave-function is that it does not itself correspond
to something which we can observe. Instead, it is only a tool by help of which
we calculate what we do observe.
To make such a calculation, quantum theory uses the following postulates.
- - -
Posted by Sabine Hossenfelder at 8:46 AM
http://backreaction.blogspot.com/2019/1 ... oblem.html
===
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Re: Even Physicists Don’t Understand Quantum Mechanics

Postby TheVat on October 23rd, 2019, 10:00 am 

New topic similar to this one, so I merged them.

See forum guidelines.
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Re: Even Physicists Don’t Understand Quantum Mechanics

Postby hyksos on June 4th, 2020, 10:34 pm 

The four dirty secrets of Quantum Mechanics.

I.
The early developers of QM proceeded with the theory without any mechanical or diagrammatic mental picture of what was being depicted. They took the math wherever it lead them.

II.
The formalism of QM does not contain particle trajectories.

III.
The formalism does not contain any random component. The equations are linear, and so admit exact solutions. This means QM is plausibly (very likely) deterministic.

IV.
There is nothing in the formalism that describes, depicts, or predicts wave function collapse.


Interpretations of QM exist to address II thru IV. They do not exist for the motivation nor the purpose to retro-fit QM back into a purely classical framework. Stated in more rough-hewn terms : the universe is not a machine.
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Re: Ghost in the Machine

Postby Faradave on June 5th, 2020, 12:49 pm 

hyksos wrote:Stated in more rough-hewn terms : the universe is not a machine.

It seems more like "the formalism of QM" is not a machine, just a mathematical abstraction. Nevertheless,

"Quantum indeterminacy is the apparent necessary incompleteness in the description of a physical system, that has become one of the characteristics of the standard description of quantum physics." - Wikipedia

This can be modeled completely by chronaxial spin of a permitting object (a hole in the continuum, representing projected contact). Its direction distributes instantly forward on a light cone (an instance of a field), for which the vertex is termed a "particle". Particles have trajectories. The lightlike 4-direction of the hole (a "pinhole") is indeterminant.
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Re: Ghost in the Machine

Postby hyksos on June 6th, 2020, 5:02 am 

Faradave » June 5th, 2020, 8:49 pm wrote:
hyksos wrote:Stated in more rough-hewn terms : the universe is not a machine.

It seems more like "the formalism of QM" is not a machine, just a mathematical abstraction. Nevertheless,

"Quantum indeterminacy is the apparent necessary incompleteness in the description of a physical system, that has become one of the characteristics of the standard description of quantum physics." - Wikipedia


I have my own opinions about this issue. In my opinion, what is likely happening is that the universe is not allowing the creation nor the annihilation of any information. One of the consequences of this is that you cannot broadcast the state of a system to several observers.

The reason is so simple that a 2nd grader can understand it.

At time t=0 you have three boxes each holding a number.

{ 18 } p

{ 29 } q

{ 74 } r


A broadcast would happen if box p transmitted the information of its state to both q and r. After transmission , at time t=1 we have


{ 19 } p

{ 18 } q

{ 18 } r

Notice that p's state has since moved on to something else, which is perfectly okay under any circumstance.


The problem comes when asking how much information the three boxes were holding at t=0 versus how much they hold at t=1. At t=0 there are 3 independent data, and so we could say something like the boxes contain 3 qubits of information. <18,29,74> At time t=1, q and r are holding a replica of the same information. And so the 3 boxes contain 2 qubits of information total. <19,18>

What happened to the third qubit? Apparently it disappeared into la-la-land.

Dissappearances into la-la-land are not permitted in a universe in which the total information in it is always constant, neither created nor destroyed. We conclude that it is impossible for any particle in this universe to broadcast its state to several observers at the same time. Instead, the universe must send one signal from one emitter to one receiver, and always exactly in pairs. ( c.r. https://en.wikipedia.org/wiki/No-broadcast_theorem )

So one might ask why a collection of human observers can all look at a lightbulb and see that it is red.

That's a good question. Here is a Mr. Richard Feynman answering the question :




Code: Select all
https://www.youtube.com/watch?v=GSwl3aGxT8w
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Re: Even Physicists Don’t Understand Quantum Mechanics

Postby hyksos on June 6th, 2020, 5:07 am 

Anyways ,

That's my response to the whole business of Von Neumann talking about projections of vectors on a Hilbert spaces. Described in detail in the the article which Faradave linked.
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