Which interpretation is your favourite?

[Schrodinger's Dog]

 

[Dmitry67]

MWI of course

 

[Schrodinger's Dog]

Of course but why?

 

[Dmitry67]

1. It is minimalistic interpretation, it does not require additional assumptions (except may be a weak form of born rule)
2. It is deterministic
3. It is realistic
4. It allows our Universe to start from very simple or null initial conditions at t=0
5. It is compatible with Max Tegmarks MUH
6. It's weirdness is beautiful

 

[Dmitry67]

BTW I don't think superstring and LQG stuff has anything to do with the Interpretations wars. While these theories will unify the gravity with other interactions, I don't expect TOE to resolve any interpretation issues.

I believe in MWI, so QM is *already* complete, and all these collapse things is just invention of the tortles.

 

[Bob_for_short]

1. It is minimalistic interpretation, it does not require additional assumptions (except may be a weak form of born rule)
2. It is deterministic
3. It is realistic
4. It allows our Universe to start from very simple or null initial conditions at t=0
5. It is compatible with Max Tegmarks MUH
6. It's weirdness is beautiful

Shut-up-and-calculate is even simpler.

 

[Dmitry67]

Yes, but it is not an interpretation. Those who claim that they use only 'Shut up and calculate' are not fair enough - they are using the interpretational things (Born rule for example) to map the number they get into what they observe. When they get 0.5498585 as a result they can say only 'I get 0.549885 after my calculations'. When they say 'I get 0.549885 and hence I expect blah blah blah they DO use interpretation, they just don't admit it.

 

[Schrodinger's Dog]

Yes, but it is not an interpretation. Those who claim that they use only 'Shut up and calculate' are not fair enough - they are using the interpretational things (Born rule for example) to map the number they get into what they observe. When they get 0.5498585 as a result they can say only 'I get 0.549885 after my calculations'. When they say 'I get 0.549885 and hence I expect blah blah blah they DO use interpretation, they just don't admit it.

Would you argue with Dirac or Feynman?

 

[Dmitry67]

Many physicists have subscribed to the instrumentalist interpretation of quantum mechanics, a position often equated with eschewing all interpretation. It is summarized by the sentence "Shut up and calculate!". While this slogan is sometimes attributed to Paul Dirac[17] or Richard Feynman, it is in fact due to David Mermin.[18]

http://en.wikipedia.org/wiki/Copenhagen_interpretation

"Shut up and calculate" is just a slogan. It really means 'When we do experiments we can forget about these weird things'. Like Big Bang, which is not a Bang at all...

 

[RUTA]

Relational Blockworld

 

[humanino]

There are many interpretations on the market. They all are interesting and have their own good features. The reason I chose "shut up and calculate" is not that I do not care about interpretations. It is because I consider most important first to be able to calculate on its own, 6 and a half days a week, while not closing one's eye on alternative interpretations on the basis of philosophical prejudice, but only do it on spare time. The vast majority of working physicists is not working on foundations, and they mostly "shut up and calculate". As far as I can tell, I have seen too often, on this very forum, people arguing about such interpretation while not being able to calculate, and I think it is vain.

 

[Bob_for_short]

There are many interpretations on the market.

Is there somewhere a detailed description of each interpretation to learn "officially" or at least sufficiently professionally?

 

[Demystifier]

I usually do not use the word "stupid" on this forum, but this time I cannot resist. What other word to use for a poll in which string theory, M-theory and LQG are proclaimed - interpretations of QM?

 

[tom.stoer]

I usually do not use the word "stupid" on this forum, but this time I cannot resist. What other word to use for a poll in which string theory, M-theory and LQG are proclaimed - interpretations of QM?

I tend to agree.

String / M and LQG are not interpretations of QM. In addition the list of interpretations is both incomplete and not detailed enough. If you read papers and books carefully you will learn that the experts are familiar with QM and philosophy; as such two people preferring the "same" interpretation will mostly differ in the details. Even Feynman was a realist in his normal course of life. He surely believed in the continuous existence of his bedroom during his labor time in the office. But of course Feynman would have never agreed to a realistic interpretation of QM. You will find many more examples ...

So I would suggest to read a book on the subject. e.g.
- Bernard d'Espagnat: On Physics and Philosophy
- Jeffrey Bub: Interpreting the Quantum World

 

[ikkyu]

I Like Transactional Interpretation.
- It explains the whole process of "wave function collapse". Wave function does not magically disappeared after it is collapsed. It canceled out as the transaction is completed.
- Wave function is physically "real" wave.
- It's time symmetric.
- Observer has no special role in collapse of wavefunction. Emitter and Absorber(Observer) of wave function are the same

http://faculty.washington.edu/jcramer/PowerPoint/AAAS_20060621.ppt

 

[Demystifier]

I Like Transactional Interpretation.
- It explains the whole process of "wave function collapse". Wave function does not magically disappeared after it is collapsed. It canceled out as the transaction is completed.
- Wave function is physically "real" wave.
- It's time symmetric.
- Observer has no special role in collapse of wavefunction. Emitter and Absorber(Observer) of wave function are the same

What are emitters and absorbers? Does this interpretation say that there are objects not defined by wave functions? Is Schrodinger equation violated at the places where emitters and absorbers are present?

 

[ikkyu]

What are emitters and absorbers? Does this interpretation say that there are objects not defined by wave functions? Is Schrodinger equation violated at the places where emitters and absorbers are present?

Emitter and Absober are exactly the charged particle that radiate the wave. E.g., electron emits/absorbs a photon during transition to another energy state.

See http://en.wikipedia.org/wiki/Wheeler–Feynman_absorber_theory" . The idea of Transactional Interpretation came from this theory.

 

[Dmitry67]

That theory has the same problem as CI.
Observer, or emitter, or absorber are not well defined and magic

 

[Demystifier]

Emitter and Absober are exactly the charged particle that radiate the wave. E.g., electron emits/absorbs a photon during transition to another energy state.

Can you write down equations that govern the behavior of this particle? Is it the classical equation of motion? Also the question that I have already asked but you didn't answer: Is Schrodinger equation violated at the positions of charged particles? Finally, what about particles without charge?

 

[Demystifier]

That theory has the same problem as CI.
Observer, or emitter, or absorber are not well defined and magic

Good point, but I'm afraid that the problem with the transactional interpretation could be even much worse than the problem with CI.

 

[Dmitry67]

Yes, it is not clear how it works for color charges, for example.

In any case, TI is a collapse interpretation, which saves the realism at cost of assuming actions backward in time.

Regarding the collapse it has the same problems as CI. For example, a mirror or a lense is not considered to be an 'absorber' even photon iteracts with atoms of the glass, while our retina is considered to be an absorber.

 

[PTM19]

To me ensemble interpretation is the way to go as it is the minimal interpretation consistent with all experiments. QM is incomplete and cannot describe individual events only their statistics.

MWI on the other hand is an abomination - the most extreme violation of Ockham's Razor one can imagine and I can't see how it solves anything as there still has to be some kind of a "collapse." Something has to determine which possibility happens to each observer since there is at least one special observer - the one in which my conscious resides - and this special observer is only experiencing one possibility and not the other so there has to be a "collapse" to determine which one it is.

 

[Dmitry67]

1
MWI on the other hand is an abomination - the most extreme violation of Ockham's Razor one can imagine and

2
I can't see how it solves anything as there still has to be some kind of a "collapse."

3
Something has to determine which possibility happens to each observer since there is at least one special observer - the one in which my conscious resides - and this special observer is only experiencing one possibility and not the other so there has to be a "collapse" to determine which one it is.

1 No, it is minimalistic. It had been discussed many times. MWI does not introduce additional postulated hence it is minimalistic

2 Quantum Decoherence

3 How do you know that your consiousness resides in only one branch?

 

[PTM19]

1 No, it is minimalistic. It had been discussed many times. MWI does not introduce additional postulated hence it is minimalistic

2 Quantum Decoherence

3 How do you know that your consiousness resides in only one branch?

1. It postulates existence of immense/infinite number of additional unobservable universes whose number is constantly growing and which are being created out of nothing.

3. Experience, there is always only one possible outcome available to my consciousness.

 

[Astepintime]

There are many interpretations on the market. They all are interesting and have their own good features. The reason I chose "shut up and calculate" is not that I do not care about interpretations. It is because I consider most important first to be able to calculate on its own, 6 and a half days a week, while not closing one's eye on alternative interpretations on the basis of philosophical prejudice, but only do it on spare time. The vast majority of working physicists is not working on foundations, and they mostly "shut up and calculate". As far as I can tell, I have seen too often, on this very forum, people arguing about such interpretation while not being able to calculate, and I think it is vain.

Agree 100%. I am also a fan of "Shut up and Calculate" and if you cannot Calculate then you should Shut Up. In the past I thought that it was quite fun and harmless to debate interpretations but now with so much quantum babble going around I am not so sure any more.

 

[Dmitry67]

1. It postulates existence of immense/infinite number of additional unobservable universes whose number is constantly growing and which are being created out of nothing.

3. Experience, there is always only one possible outcome available to my consciousness.

1. It does not postulate the existence of such universes! This is a very common misconception.

2. So, how does it deny the MWI view? As branches loses an ability to communicate after very short period of time, both "you" in 2 branches are claiming that "there is always only one possible outcome available to my consciousness"

 

[PTM19]

1. It does not postulate the existence of such universes! This is a very common misconception.

2. So, how does it deny the MWI view? As branches loses an ability to communicate after very short period of time, both "you" in 2 branches are claiming that "there is always only one possible outcome available to my consciousness"

1. How does it not postulate them? Maybe not explicitly but that doesn't matter. Compare for example ensemble or Copenhagen interpretation and MWI, observable physics is exactly the same yet one has an immense number of unobservable parallel universes which are constantly being created and the others do not, where does the difference come from if not from postulates of the MWI interpretation?

2. It does not deny it, it shows that it suffers from a certain indeterminism somewhat similar to standard measurement problem. To understand my point you have to realize that there is at least one special conscious observer - in your case it is yourself, in my case it is myself. My consciousness is confined to one branch only making this branch special to me. Even if I assume there are "copies" of me in parallel universes right now (and new ones constantly branch off) those copies are not really me since I can never control them or experience what they do, what's more their history differs from mine. So now the problem is when a measurement occurs what determines which outcome happens in my branch? From my perspective the outcome is indeterministic.

 

[Dmitry67]

1. No, it DOES matter. MWI has *less* axioms then CI because it does not have collapse. Youre right, it creates more "stuff", but exactly the same argument you can use against GR in comparison with a sphere of fixed stars, because GR "postulates"

It postulates existence of immense/infinite number of additional unobservable universes whose number is constantly growing and which are being created out of nothing (c) PMT19

This is exactly what GR predicts (if universe is open) - an infinite number of unobservable Hubble voulmes, and more and more expension!

This is a pure psycological thing: it is very easy to accept the SPACIAL infinity (the existence of infinite number of worlds far away from our) but difficult to accept the same infinity of worlds which are in the same place spacialy but which do not communicate.

2. This is circular. You assume the collapse saying "My consciousness is confined to one branch only making this branch special to me". I don't assume it.

So, there are 2 branches. MWI predicts that both copies are equally conscious, share the same memory and are not aware of each other because of the decoherence. So each copy will say: "Only MY branch is real! But the choice of a branch was RANDOM" This is exactly what MWI predicts and this is exactly what happens. There is no indetermminism at all.

 

[Fredrik]

The difference between ensemble/copenhagen* and the MWI is that the former assumes that QM doesn't tell us what actually happens, while the MWI assumes that QM does tell us what actually happens. That makes it the minimal realist interpretation, because it doesn't contain additional axioms which serve no other purpose than to get rid of the many worlds (like the version of Copenhagen that asserts that there's a mysterious physical process called "wavefunction collapse" that replaces a superposition with an eigenstate).

(I recently questioned the assertion that the MWI requires no additional axioms here, but due to too many distractions I haven't really thought it through yet, so I'm still not sure about this).

Decoherence isn't a problem for the MWI. Quite the opposite. It just singles out the worlds in which a system's environment can contain stable records of the state of the system. A memory about a result of a measurement in a physicist's brain is such a stable record, so only the worlds that are singled out by decoherence theory can contain conscious observers.

*) See this thread for a discussion about those terms.

By the way, I also think the claim that the number of worlds is growing is incorrect. The claim that they're being "created out of nothing" is definitely incorrect.

 

[PTM19]

1. No, it DOES matter. MWI has *less* axioms then CI because it does not have collapse. Youre right, it creates more "stuff", but exactly the same argument you can use against GR in comparison with a sphere of fixed stars, because GR "postulates"

It postulates existence of immense/infinite number of additional unobservable universes whose number is constantly growing and which are being created out of nothing (c) PMT19

This is exactly what GR predicts (if universe is open) - an infinite number of unobservable Hubble voulmes, and more and more expension!

This is a pure psycological thing: it is very easy to accept the SPACIAL infinity (the existence of infinite number of worlds far away from our) but difficult to accept the same infinity of worlds which are in the same place spacialy but which do not communicate.

2. This is circular. You assume the collapse saying "My consciousness is confined to one branch only making this branch special to me". I don't assume it.

So, there are 2 branches. MWI predicts that both copies are equally conscious, share the same memory and are not aware of each other because of the decoherence. So each copy will say: "Only MY branch is real! But the choice of a branch was RANDOM" This is exactly what MWI predicts and this is exactly what happens. There is no indetermminism at all.

1. Your comparison is not valid since GR is the best description of experimental results while MWI doesn't offer any additional predictive power over other interpretations. If some alternative theory existed which gave exactly the same experimental predictions as GR but didn't require singularities or event horizons it would of course be preferable.

2. It is not circular, and I do not assume collapse, if you agree with "I think therefore I am." then it follows from there - you are special due to your consciousness and that there is at least only one such observer.

Or to put in a different way - one can explain anything one wants by postulating parallel universes in which other possibilities take place making distributions normal or explaining otherwise unexplainable phenomena but this is not physics since it has no predictive power and is not falsifiable.

For example why matter dominates? It doesn't! We are just in a universe where it happens to be more abundant but there are other parallel universes where antimatter is more abundant and on average they are equally likely to dominate.

Does it solve the problem? Is such a solution satisfactory to you?

To me it doesn't solve anything since we want to know what made it dominate in *our* universe, we don't care about parallel unobservable universes. The fact that matter dominates here means that there was some process in our universe which lead to it and the problem will only be solved when we understand that process.

Or another example why do particles decay when they do? They decay when a particle in a parallel universe comes through exactly the same location they occupy in our universe! So particle decay is deterministic after all, and there is nothing to worry about.

A similar explanation can be invented for anything you want, is this physics?

 

[PTM19]

1. The difference between ensemble/copenhagen* and the MWI is that the former assumes that QM doesn't tell us what actually happens, while the MWI assumes that QM does tell us what actually happens. That makes it the minimal realist interpretation, because it doesn't contain additional axioms which serve no other purpose than to get rid of the many worlds (like the version of Copenhagen that asserts that there's a mysterious physical process called "wavefunction collapse" that replaces a superposition with an eigenstate).

1. You say "it [is] the minimal realist interpretation, because it doesn't contain additional axioms which serve no other purpose than to get rid of the many worlds" but this is completely backwards, there is no such thing as "many worlds" beyond MWI interpretation. There is no such thing in the rest of physics, it is precisely MWI that postulates "many worlds."

It's as if I developed an interpretation invoking ghost of ancestors and then claimed that all other interpretations require axioms to get rid of ghost of ancestors while mine doesn't so it is clearly minimal.

Ensemble is minimal since it doesn't require one to believe in anything beyond what can be experimentally verified. Instead one has to accept our ignorance - we don't know what exactly happens with single events. But even Copenhagen interpretation with it's mysterious wavefunction collapse is much better then the mysterious multiverse for which there is no justification whatsoever. I'd rather have one mysterious process then the whole mysterious multiverse.

To me MWI looks like nothing more then an elaborate rationalization invented in order to save QM from it's problems. MWI interpretation requires one to take existence of immense number of unobservable parallel universes on nothing but belief, how is that scientific or minimal? Especially when the second interpretation requires no such thing and gives exactly the same predictions? MWI flies in the face of both scientific skepticism and Ockham razor.

2. (I recently questioned the assertion that the MWI requires no additional axioms here, but due to too many distractions I haven't really thought it through yet, so I'm still not sure about this).

3. Decoherence isn't a problem for the MWI. Quite the opposite. It just singles out the worlds in which a system's environment can contain stable records of the state of the system. A memory about a result of a measurement in a physicist's brain is such a stable record, so only the worlds that are singled out by decoherence theory can contain conscious observers.

*) See this thread for a discussion about those terms.

4. By the way, I also think the claim that the number of worlds is growing is incorrect.

5. The claim that they're being "created out of nothing" is definitely incorrect.

2. Thanks for the links I'll have a look at them.

3. Yes, but I'm not sure how it ties to what I said.

4. How can it not grow? Do some universes get erased or merge?

5. We have one universe before measurement and 2 after if it's not created out of nothing then where did the energy and matter come from for one extra universe?

 

[Dmitry67]

PTM19, before I reply, do you accept the Quantum Decoherence or not?
If you do, do you see it as answer to the Measurement problem or not?
(My answer depends on your position)

 

[Dmitry67]

5. We have one universe before measurement and 2 after if it's not created out of nothing then where did the energy and matter come from for one extra universe?

Check the MWI FAQ
Common objections and misconceptions http://en.wikipedia.org/wiki/Many-worlds_interpretation#Common_objections_and_misconceptions

for example:
Conservation of energy is grossly violated if at every instant near-infinite amounts of new matter are generated to create the new universes.
MWI response: Conservation of energy is not violated since the energy of each branch has to be weighted by its probability, according to the standard formula for the conservation of energy in quantum theory. This results in the total energy of the multiverse being conserved.

 

[PTM19]

PTM19, before I reply, do you accept the Quantum Decoherence or not?
If you do, do you see it as answer to the Measurement problem or not?
(My answer depends on your position)

Personally as I said I accept ensemble interpretation and that we don't know what happens in the case of individual events - we can only make predictions about an ensemble.

But I don't see how decoherence can solve the problems of MWI I mentioned if that answers your questions.

 

[PTM19]

Check the MWI FAQ
Common objections and misconceptions http://en.wikipedia.org/wiki/Many-worlds_interpretation#Common_objections_and_misconceptions

for example:
Conservation of energy is grossly violated if at every instant near-infinite amounts of new matter are generated to create the new universes.
MWI response: Conservation of energy is not violated since the energy of each branch has to be weighted by its probability, according to the standard formula for the conservation of energy in quantum theory. This results in the total energy of the multiverse being conserved.

But this is a complete redefinition of conservation of energy - we are dealing with macroscopic world and in macroscopic world there is no weighting of energy by probability.

Besides it doesn't even make sense since before measurement there exist n universes (with probability equal to 1) and after measurement there are n+1 universes (with probability equal to 1) so what probability is that supposed to be that we use to weigh energy with?
If MWI is deterministic as it claims how can there be a probability of a branch?

Finally as I said before one can explain anything that way - you can make any quantity you want conserved if you place the right amount in parallel universes - this is not science.