The Observer Effect

[joigus]

8 hours ago, Luc Turpin said:

Wish to continue our conversation. I am confused, because some see a role for consciousness in quantum mechanics and I see none.  

 

 

Who said consciousness?

I mean, besides you, of course.

 

[exchemist]

10 hours ago, Luc Turpin said:

Wish to continue our conversation. I am confused, because some see a role for consciousness in quantum mechanics and I see none.  

 

 

Nowadays that is a rather out of date view. A lot of misconceptions have arisen, historically, due to the choice of words made when originally formulating QM. They spoke - and we still speak - of "observable" properties and "observers", "observation" collapsing the wave function and so forth.  

Some people thought that "observation" implied a conscious entity to do the observing. But a moment's reflection shows you that can't make sense. Does anyone seriously contend that the reading on the dial changes when the observing experimenter goes off to get a cup of coffee? And what if the experiment is "observed" by the laboratory cat? Or a passing wasp? It's bonkers. 

The modern view is that it is interaction with another quantum system that collapses the wave function.  So that can be part of a measuring device, whether or not anyone is looking at the measurement. 

Those people nowadays that maintain a role for consciousness in QM tend to be quantum woo charlatans like Deepak Chopra.

 

[Luc Turpin]

I was once one of them that misinterpreted words like the observer effect to be just that; this showed my weak science background in QM;  however, I am still puzzled by the Roger Penrose, von Neumann, Wigner, Wheeler, Stapp and Kafatos of the world who espouse such aspect of the theory. Founder of the theory (Bohr, Heisenberg, Schrodinger, Plank, JOrdan, Pauli and Dirac) also seemed to edge their bets toward a role of consciousness in QM.

Also, Studiot's text provided above says: “By observing the world, we participate in making it”. I am unaware of the author's name

And, finally, Dean Rarin’s five signa experimentation, although “quirky”, seems to show a very weak effect of consciousness in the double-slit experiment. If this line of experimentation pans out and I am not sure it will, then the question remains open.

[joigus]

The brain is but one particular physical system riddled with decoherence. Why would we need a brain to explain, eg, the formation of the Solar System about 4.7 billion years ago? That is but another particular example of a physical system riddled with decoherence, to be sure.

Physicists of Bohr's generation, and Wigner, and so on, were very confused by the postulate of projection. That's why they invoked consciousness.

Nobody plays that game anymore.

[studiot]

17 minutes ago, joigus said:

postulate of projection

Would you care to elaborate please ?

[Luc Turpin]

Where is consciousness in the brain; no yet found it. Also, Penrose and Radin, for example, still play the game.

 

By the way, I am very grateful of being able to have such conversations; i know that I am a bit off the beat and espouse radical ideas; but thanks all of you very much!

[joigus]

7 minutes ago, studiot said:

Would you care to elaborate please ?

With pleasure. As an appetizer,

https://en.wikipedia.org/wiki/Mathematical_formulation_of_quantum_mechanics#Effect_of_measurement_on_the_state

Quote

Postulate II.c

If the measurement of the physical quantity  on the system in the state  gives the result , then the state of the system immediately after the measurement is the normalized projection of  onto the eigensubspace associated with 

This, of course, is not a projection, although it involves one. A projection is linear, and the denominator couldn't be farther from linearity in \( \left|\psi\right\rangle \). If we dismiss the denominator, interpreting it as some kind of ad hoc convention (more epistemic than embodying actual physics), then \( P_{n}\left|\psi\right\rangle \) is not unitary.

So the result of postulate II.c cannot be the result of any approximation in the interaction term from the Schrödinger equation (the Hamiltonian). It just can't.

That's why people today don't admit to II.c reflecting in any way the actual physics. If we did, we would have to admit that is beyond physics (consciousness, or what may have you.)

[studiot]

1 hour ago, exchemist said:

Nowadays that is a rather out of date view. A lot of misconceptions have arisen, historically, due to the choice of words made when originally formulating QM. They spoke - and we still speak - of "observable" properties and "observers", "observation" collapsing the wave function and so forth.  

Some people thought that "observation" implied a conscious entity to do the observing. But a moment's reflection shows you that can't make sense. Does anyone seriously contend that the reading on the dial changes when the observing experimenter goes off to get a cup of coffee? And what if the experiment is "observed" by the laboratory cat? Or a passing wasp? It's bonkers. 

The modern view is that it is interaction with another quantum system that collapses the wave function.  So that can be part of a measuring device, whether or not anyone is looking at the measurement. 

 

+1

In particular I find the idea of 'collapsing' of a wave function over dramatic.
This was the reason for my question to Luc about differential equations and there is more detail later in this post, or my next one.
Also I agree that the interaction is a far more sober term to use than observer.

 

18 minutes ago, joigus said:

With pleasure. As an appetizer,

https://en.wikipedia.org/wiki/Mathematical_formulation_of_quantum_mechanics#Effect_of_measurement_on_the_state

This, of course, is not a projection, although it involves one. A projection is linear, and the denominator couldn't be farther from linearity in |ψ〉 . If we dismiss the denominator, interpreting it as some kind of ad hoc convention (more epistemic than embodying actual physics), then Pn|ψ〉 is not unitary.

So the result of postulate II.c cannot be the result of any approximation in the interaction term from the Schrödinger equation (the Hamiltonian). It just can't.

That's why people today don't admit to II.c reflecting in any way the actual physics. If we did, we would have to admit that is beyond physics (consciousness, or what may have you.)

Thanks +1

I am rather concerned about the statement

23 minutes ago, joigus said:

immediately after the measurement

Because it implies that there is only one measurement, unless they are using measurement to mean interaction (observation) as above.
 

My concern is that quantum interactions are not of the 'only one' type. That is the point of the Uncertainly Principle and the Commutator.

 

[Genady]

38 minutes ago, Luc Turpin said:

Penrose and Radin, for example, still play the game.

Penrose does not involve consciousness to explain quantum mechanics, but rather he tries to involve quantum mechanics to explain consciousness.

[joigus]

7 minutes ago, Genady said:

Penrose does not involve consciousness to explain quantum mechanics, but rather he tries to involve quantum mechanics to explain consciousness.

Right. I missed that one.

16 minutes ago, studiot said:

My concern is that quantum interactions are not of the 'only one' type. That is the point of the Uncertainly Principle and the Commutator.

Would you care to elaborate, please?

[studiot]

On 12/1/2023 at 1:48 AM, Luc Turpin said:

To Studiot

I do not know how to paste your last comment like others do, so I am responding in the best way that I can.

You indicated in your last post, the following: Please let us know if you understand what a differential equation is.

My answer: I have a very vague appreciation of what a differential equation is.

Also, read with great interest the text that you provided.

Have you now found out how to use the quote funtion ?

 

Thank you for answering my question. This is good that you have heard of them.  We can proceed from there, though I am trying to avoid more advanced mathematics.

 

~~So for an ordinary, or for our purposes an algebraic equation, has a solution or solutions which are numbers.

for example the solution to x+3 = 7 is x = 4; quadratic equations (involving the squre of something) have two solutions, also numbers.

A function is the complete set of values (numbers)  of a more complicated expression or equation.

The solution or solutions (note the plural) to a differential equation is not a number but a function or functions.

So here is a classical situation that leads to a quadratic equation.

In the current Russia - Ukraine conflict both sides have 'dug in' below the level of high ground.
So when firing at each other the projectiles need to clear the high gound, trees, walls etc and land below their firing point.

 

The details of the mathematics don't matter, the details of the physical reality do.

I have sketched the path on one such a projectile and set the origin of coordinates at its firing point .

The path is a plot of a function. The function has a quadratic equation, so has two solutions.

No one bats an eyelid when I say tha there is only one solution that intersects reality - the target position.

Yet the other solution remains mathematically, and is always there even thougn its position is both behind the firing position and underground.

 

So onward to quantum theory.

The equations of QM are differential equations whose solutions are functions.

Eminently much more complicated than my target practice example.

But just the same, all the solutions are always there mathematically.

And just the same the intersection with the real material world selects one particular solution and makes it real.

But for some reason too many cry Magic, Collapse and other dramtic words.

 

How are we doing are you following my drift ?

If so I hav emore to say on some other choice terminology, particularly ones Wilczek introduced.

Since you asked here is the book the quotes are from.

 

You may also like this one by Professor Robert Mills, of Yang Mills Theory.

 

 

[Luc Turpin]

2 hours ago, studiot said:

Have you now found out how to use the quote funtion ?

 

Yes!

Also understood your explanation removing the “magic”. 

[studiot]

48 minutes ago, Luc Turpin said:

Yes!

Also understood your explanation removing the “magic”. 

That's good, so we can move on.

 

5 hours ago, Luc Turpin said:

I was once one of them that misinterpreted words like the observer effect to be just that; this showed my weak science background in QM;  however, I am still puzzled by the Roger Penrose, von Neumann, Wigner, Wheeler, Stapp and Kafatos of the world who espouse such aspect of the theory. Founder of the theory (Bohr, Heisenberg, Schrodinger, Plank, JOrdan, Pauli and Dirac) also seemed to edge their bets toward a role of consciousness in QM.

On thing to note is that the mathematics of probability and statistics was not properly understood in their time.

Startling though this my seem, both suffered from the shadow of Fisher, Pearson and Gosset through the end of the 19th and into the early 20th centuries.
These men were not wrong but just dominated and thereby limited the subject until the mid and latter 20th century.
The first physics text I know of to acknowledge that there are at least four significanly different meanings to the term 'probability' is in the Manchester Physics series

Statistics - A guide to the use of Statistical Methods in the Physical Sciences by Barlow, published in 1989.

 

I also note that there remain questions we do not know the answers to in Quantum theory, it is not perfect  and has been continually updated from its inception.

One of its founding principles, in Physics is that everything you might want to know, or indeed can know about the material world, can be derived from the wave function.

But there have been bumps in this road. The first was the change from the original formula for the energy of an oscillator from nhν  to (n+ ½)hν to introduce the so called zero point energy. The original theory was called the 'old quantum theory' and the replacement called the 'new quantum theory'.

The second was the realisation that the original set of 3 quantum numbers (from the solutions to the quantum wave equation)   was deficient and a fourth number not appearing in that equation was added. This fourth one was the spin quantum number.

Who can tell what the next one will be ?

 

Back to  Wilczek

He starts the section I post with his word 'Complementarity'.

Now Yin and Yang or the idea of 'Two sides of the same coin' are thousands of years old.
This is one idea the ancients got dead right.

But they ancients did not have our mathematical sophistication to take it any further.
We now know that what mathematicfians call duality and reserve complementarity for something different (I will explain in a moment) appears all over mathematics and the physical sciences. Even school mathematics.

Some schools like to find practical demonstrations of maths and one such is an art or craft called curve stitching.

How do you make a circle ?

Well one way is to fix the centre and use a string and pencil to draw the circumference.
Another way is to work you way round the circumference drawing tangents. This is done by stretching strings across suitable points outside the circle, all the way round.

This dualism reappears in very advanced applied maths, in relativity, cosmology, engineering and other places using the duality provided by the relationship between an object and its boundary.

But a line of strung tangents is not the same as a centre peg and radius, though they both show aspects of the same thing and each shows other things besides that are not shown by the other half of the dual.

So it is with wave -  particle dualism.

Light shows neither all the characteristics of waves nor all the characteristics of particles, and you have to set your show up in advance to see either one or the other.
You will never see both at the same time.

It was these real observations in the material world about one or the other, but not both at the same time, that led Einstein to propose the word 'quanta' for the quantum characteristics and the rest is, as they say, history.

OK complementarity  Wilczek is a very talented physicist.

Mathematicians use this term to denote mathematical objects that take complements.

When we solve the Wave (differential) equation we are looking for solutions (there are an infinity of them) in what is known as the space if square integrable functions.

That mouthful tells us the to form the square we are looking for functions and their 'complement'.

Usually squaring something means to multiply by itself but

Squaring such functions involves not multiplying by itself but multiplying by its complement.

One result falling out of such a procedure is that order of multiplication becomes important because A*its complement is not equal to its complement*A.

The Heisenberg Uncertainty principle can be derived from this.

Telling you about the Physics, Wilczek describes how there are some pairs of quantities that when you measure them both the result depends upon the order of measurement in a similar fashion.

In fact there is a similar theorem in the classical wave equation for a vibrating stretched string so it does not only occur in Quantum Theory.

 

I think that is enough for the next installment, see if you can pick out these and any other important points from my Wilczek post.

 

 

[Luc Turpin]

17 minutes ago, studiot said:

 

One of its founding principles, in Physics is that everything you might want to know, or indeed can know about the material world, can be derived from the wave function.

 

Thanks for all of this.  It is much more than I expected. I get the some-most of it, but have to read and re-read to fully understand. I will try and get my hands on the Wilczek book.  Finally, If the above statement is still valid, this is still magic to a neophyte like me. Also, zero-point energy, non-locality, tunneling etc. (if I understand correctly) are, as well, magic to someone like me.

[exchemist]

7 minutes ago, Luc Turpin said:

Thanks for all of this.  It is much more than I expected. I get the some-most of it, but have to read and re-read to fully understand. I will try and get my hands on the Wilczek book.  Finally, If the above statement is still valid, this is still magic to a neophyte like me. Also, zero-point energy, non-locality, tunneling etc. (if I understand correctly) are, as well, magic to someone like me.

Zero point energy, at least, is fairly easy to grasp. All you need is the idea that in QM there is a ground state, in other worlds a lowest energy state that a given system can occupy, and that, in this state (depending on what kind it is), it may be that some residual energy remains present. The electron in the ground state of the hydrogen atom, for instance, still has some potential and kinetic energy. That is zero point energy, i.e. energy that remains in the atom. The same is true for the vibrational ground state of a molecule in which 2 or more atoms are joined by chemical bonds, which vibrate thermally. They still move a bit, even at absolute zero, because there is residual energy in the vibrational ground state.  (In molecular rotation, on the other hand, the ground state has no residual kinetic energy, so there is no zero point energy of rotation, i.e. molecules do stop spinning at absolute zero.)

What people find harder is the concept of a zero point energy of the vacuum. That will require more reading. 

[KJW]

On 12/1/2023 at 7:29 PM, joigus said:

I need to understand what happened to the rest of the amplitude that "collapsed".

When a pure quantum state is measured, it is decomposed into a complex-number weighted sum of eigenstates. However, only a single eigenstate is observed as the result of the measurement, and this is chosen randomly with a probability based on the complex-number weighting of the eigenstate. If a large number of identical pure quantum states are identically measured, then the various eigenstates will be observed with their respective probabilities. For example, in the double-slit experiment, each spot corresponds to a random position eigenstate, but the accumulation of spots is an interference pattern resulting from each quantum state passing through both slits.

In the Copenhagen interpretation, the pure quantum state collapses randomly to a single eigenstate, and the other possible eigenstates simply vanish. But in the many-worlds interpretation, the different versions of the observer in the different worlds observe all of the possible eigenstates. And because all the eigenstates are mutually orthogonal to each other, there is no interference between them, and thus the observer can observe only a single eigenstate and not the other versions of the observer.
 

[Luc Turpin]

48 minutes ago, exchemist said:

 

What people find harder is the concept of a zero point energy of the vacuum. That will require more reading. 

Quite correct

 

its zero point energy of the vacuum that I meant and I have a lot  of reading to do to comprehend it

[joigus]

13 minutes ago, KJW said:

In the Copenhagen interpretation, the pure quantum state collapses randomly to a single eigenstate, and the other possible eigenstates simply vanish. But in the many-worlds interpretation, the different versions of the observer in the different worlds observe all of the possible eigenstates. And because all the eigenstates are mutually orthogonal to each other, there is no interference between them, and thus the observer can observe only a single eigenstate and not the other versions of the observer.
 

Thank you. Yes, I'm familiar with it but it's not falsifiable, so I don't consider it an explanation of what I want to understand. Invoking a new universe every time a leaf makes a ripple on a pond is what I would call an ad hoc explanation.

[exchemist]

53 minutes ago, Luc Turpin said:

Quite correct

 

its zero point energy of the vacuum that I meant and I have a lot  of reading to do to comprehend it

Yes you need not just QM but QFT, or QED (as a mere chemist, I remain a bit hazy about the distinction). 

[KJW]

23 minutes ago, joigus said:

Yes, I'm familiar with it but it's not falsifiable, so I don't consider it an explanation of what I want to understand.

That's the problem with the requirement of falsifiability: Reality is not obligated to reveal itself in its entirety. It may be that the many worlds actually do exist, but are unobservable because they are mathematically orthogonal to each other. By rejecting the many worlds on the grounds that they are not falsifiable, one then has a reality that is inexplicable.

 

 

24 minutes ago, joigus said:

Invoking a new universe every time a leaf makes a ripple on a pond is what I would call an ad hoc explanation.

I personally don't interpret the many-worlds interpretation as a splitting of realities each time a quantum decision is made. Instead, I regard all the spacetimes as existing from the very beginning, at least conceptually (I don't think reality is as simple as multiple spacetimes).

 

 

[Genady]

18 minutes ago, exchemist said:

QFT, or QED (as a mere chemist, I remain a bit hazy about the distinction).

QFT is a mathematical framework. QED is a physical model.

[joigus]

8 minutes ago, KJW said:

I personally don't interpret the many-worlds interpretation as a splitting of realities each time a quantum decision is made. Instead, I regard all the spacetimes as existing from the very beginning, at least conceptually (I don't think reality is as simple as multiple spacetimes).

 

The problem, to me, is that we have to spend time discussing how to interpret an interpretation. The least an interpretation should be asked to do is to dispell any need to interpret the interpretation. Also, personal views should be not necessary.

[KJW]

21 minutes ago, joigus said:

The problem, to me, is that we have to spend time discussing how to interpret an interpretation. The least an interpretation should be asked to do is to dispell any need to interpret the interpretation. Also, personal views should be not necessary.

It's not really an interpretation of an interpretation, but more like saying that the notion of the splitting of realities is a strawman that should not be used to reject the many-worlds interpretation of quantum mechanics. In truth, all I am saying is that in the Born rule, all the eigenstates exist, and that it is merely a first-person perspective that gives rise to the observation of only a single eigenstate. Although I am saying that the many worlds is the ontological reality, and that the Copenhagen interpretation is the subjective observation of the many worlds, I am not claiming to fully understand the precise details of the many worlds.

 

[joigus]

16 minutes ago, KJW said:

It's not really an interpretation of an interpretation,

I was just quoting you:

1 hour ago, KJW said:

I personally don't interpret the many-worlds interpretation as a splitting of realities each time a quantum decision is made. Instead, I regard

You seem to be interpreting an interpretation. I understand your predicament. It's not easy to make sense of it in your mind.

In your answer it seems clear that you invoke the observer in order to distinguish the alternative that comes out of the measurement:

1 hour ago, KJW said:

In truth, all I am saying is that in the Born rule, all the eigenstates exist, and that it is merely a first-person perspective that gives rise to the observation of only a single eigenstate.

But why do many observers agree upon the same alternative having been realised? Why do these multiple observers all get split into the same "congruence of observers" seeing the same thing? Why do you need an observer?

I don't see any strawman in showing dissatisfaction with that state of affairs. I'm not aware that the many-worlds interpretation (orthogonal worlds interpretation if you'd rather call it that way) has made much progress in any direction except to ease the minds of some of the uncomfortable ones. Oh, don't worry, all the observers that disagree with us all have gone into an orthogonal alternative congruence of observers.

I'm still uncomfortable, perhaps that's all I can say. Along with the confession that perhaps I haven't interpreted something essential in that interpretation either.

[Luc Turpin]

I am starting to get a bit of a better handle on all of this, but still very-very far from general unserstanding.

QM math is solid (no surprise there); how it works is also solid (no surprise there also), but I sense more ambiguity on what it all means. Am I right?

Also, a more technical question: Can the brain be a quantum system able to interact with other quantum systems? Base on some of Joigus earlier comments, I believe so

Lastly, collapse, interaction and decoherence are all the same?