Can Wigner’s Friend Lie?

originally posted by: neoholographic
a reply to: Direne
If QM has nothing to do with the structure of the universe, how did you get the galaxy era without the Planck epoch?

I wouldn't say QM has nothing to do with the structure of the universe.

I would say that the structure of the universe cannot be explained by QM alone, because the standard model (a QM model) does not include gravity, nor does it include most of the mass in the universe known as dark matter. A model that can successfully explain the structure of the universe must consider those two things missing from the current standard model:

A New Map of All the Particles and Forces

The Standard Model is missing a few puzzle pieces (conspicuously absent are the putative particles that make up dark matter, those that convey the force of gravity, and an explanation for the mass of neutrinos), but it provides an extremely accurate picture of almost all other observed phenomena.

This is not in dispute that the standard model is incomplete, everyone agrees that it's incomplete and doesn't include dark matter and gravity. I have yet to see anybody explain the large scale structure of the universe without dark matter and gravity.

a reply to: neoholographic

neoholographic, did you know that there are plenty of exact solution to Einstein's field equations in which matter is not present, at all? Didn't you know quantum effects only appear when matter is present? There is one concept you forget: spacetime can be empty; devoid of particles, yet, gravity persists because gravity is created by spacetime metrics. Gravity is indeed a field. The only one we know.

Now, tell me, what role could possibly play your QM in an empty spacetime? I'll answer for you: none.

a reply to: Direne

You don't understand Quantum Mechanics at all!

It's like I'm debating someone who lived in the 1700's, died and woke up in 2020 and doesn't realize there's been 300 years of scientific discovery

First off, quantum effects don't only exist when matter is present. Virtual particles are always popping into and out of existence so there can't be a perfect vacuum. The Uncertanty Principle captures this..

In quantum field theory, the quantum vacuum state (also called the quantum vacuum or vacuum state) is the quantum state with the lowest possible energy. Generally, it contains no physical particles. Zero-point field is sometimes used as a synonym for the vacuum state of an individual quantized field.

According to present-day understanding of what is called the vacuum state or the quantum vacuum, it is "by no means a simple empty space".[1][2] According to quantum mechanics, the vacuum state is not truly empty but instead contains fleeting electromagnetic waves and particles that pop into and out of the quantum field.[3][4][5]

en.wikipedia.org...

This is like debating a 10th grader that's curious about QM but with you it's worse because you're just spouting lies. You talked about empty spacetime. There's no such thing as empty space. This is QM 101. Here's more about the vacuum.

In quantum mechanics and quantum field theory, the vacuum is defined as the state (that is, the solution to the equations of the theory) with the lowest possible energy (the ground state of the Hilbert space). In quantum electrodynamics this vacuum is referred to as 'QED vacuum' to distinguish it from the vacuum of quantum chromodynamics, denoted as QCD vacuum. QED vacuum is a state with no matter particles (hence the name), and no photons. As described above, this state is impossible to achieve experimentally. (Even if every matter particle could somehow be removed from a volume, it would be impossible to eliminate all the blackbody photons.) Nonetheless, it provides a good model for realizable vacuum, and agrees with a number of experimental observations as described next.

QED vacuum has interesting and complex properties. In QED vacuum, the electric and magnetic fields have zero average values, but their variances are not zero.[34] As a result, QED vacuum contains vacuum fluctuations (virtual particles that hop into and out of existence), and a finite energy called vacuum energy. Vacuum fluctuations are an essential and ubiquitous part of quantum field theory. Some experimentally verified effects of vacuum fluctuations include spontaneous emission and the Lamb shift.[18] Coulomb's law and the electric potential in vacuum near an electric charge are modified.[35]

en.wikipedia.org...

So space is never empty. It's always filled with vacuum energy so quantum systems are never at rest. We know because of E=MC squared that energy can be converted to mass and vice versa. This is QM 101. Here's a simple visualization that you will see in a High School science course.

When you look at the difference between a classical harmonic oscillator and a quantum harmonic oscillator, it illustrates this point.

Here's a picture of a classical harmonic oscillator.



This shows that the lowest energy that a classical oscillator can have is zero. So think of a pendulum that eventually stops swinging at it's lowest energy state. So you will start with big swings of the pendulum and it's furthest away from it's lowest energy state, but the swings will get slower and slower and eventually come to a full stop.

Here's a pic of a quantum harmonic oscillator.



What this shows is that even at it's lowest energy state, a quantum system always has non zero energy. It's always moving. So think of a pendulum that's never at rest because it's lowest energy state is always non zero.

Again, this is basic QM and sadly we can't debate the OP because you keep making these egregious statements that have no basis in fact. I suggest you take a basic online study course on QM. They have free ones online and stop wasting time. You're statement is so full of lies I can keep going but again, it's a waste of time. If you're not willing to learn the basics, you will just keep spouting nonsense.

a reply to: neoholographic

Virtual particles are always popping into and out of existence

Lol. neo! virtual particles ... what's next? Invisible observers? Virtual ones? It seems to me you are mixing up some bad comics readings with a lot of Wikipedia. Is that your source of ignorance?

So space is never empty

Space, neo? Are you refering to spacetime? I tell you so because nobody ever talks about space as you call it. There is no space. There is spacetime. The only vacuum you might possibly know is the interior of your head.

the lowest energy that a classical oscillator can have is zero

Neo, zero energy is exactly the worst outcome for your deranged theory. See, if the oscillator has zero energy then that would mean it has zero mass. Tell me, what happens to the oscillator when it comes to rest? Does it have zero mass? Oh, I guess... it becomes a neoholographic virtual oscillator .

Face it, it is not only that you don't understand quantum mechanics at all, it is worse: you don't even understand simple mechanics. Were you to have at least a basic knowledge of how to use a screwdriver you could fix the loose nut in your hollow head. Just try, don't be lazy.

a reply to: Direne

You must be a troll. Nobody comes into a science forum this illiterate about science.

At the end of the day, I don't mind. Someone that may have questions about these things may learn more about QM. It's obvious that you don't understand or can't grasp the basics.

Here's more on virtual particles:

Virtual particles are short-lived particles that cannot be directly detected, but that affect physical quantities—such as the mass of a particle or the electric force between two charged particles—in measurable ways.

The existence of virtual particles is a purely quantum-mechanical phenomenon. The particles can appear out of nothing—the vacuum—only to quickly disappear back into the vacuum. Or they can be emitted by real particles, travel a short distance and disappear again as they interact with other particles. The Heisenberg uncertainty principle limits the duration of their fleeting existence and the distance they can travel.

www.symmetrymagazine.org...

You act like virtual particles are akin to virtual reality. This just means this sea of non zero energy is converted to particles via quantum fluctuations but these particles don't become real particles and only last for a small amount of time that's limited by the Uncertainty Principle but they have a measurable effect that explains some of the things that are observed.

It's virtual particles that explain why black holes evaporate and how quantum information can escape a black hole. Now, I know this is something you will not understand because you can't grasp basic QM, but others reading this may be interested.

When virtual particle pairs come into existence near the event horizon of a black hole, one of these particles can fall into the black hole while the other escapes. The virtual particle that doesn't fall into the black hole becomes a real particle but it comes at a cost. The black hole loses some of its mass and it escapes via Hawking radiation.

As many more of these virtual particle pairs pop into existence, the more mass the black hole will lose as one of these pairs falls into the black hole and the black hole evaporates.

What's interesting is, this could be the basis for things like spacetime and emergent gravity.

The information that's encoded on the 2d surface of the the black hole's event horizon escapes as the black hole evaporates according to some scientist. This is because of entanglement between the particle that fell into the black hole and the outgoing Hawking radiation. This entanglement could form the very fabric of spacetime and gravity could emerge from the entropy of entanglement.

There's a lot more to this but I will stop there.

The point is, virtual particles doesn't mean virtual reality. They're real and a consequence of this sea of vacuum energy but that shouldn't be surprising because of E=MC squared.

You then said, zero energy would mean zero mass which is again, an asinine comment but another lie that needs to be addressed.

Zero energy just means an object with rest mass is not moving through space. We all move through time at the speed of light. When we move through space, we move slower through time which is just time dilation which has been confirmed in experiments. The faster an object with rest mass moves through space, the slower it moves through time which gives you things like the twin paradox.







So an object with rest mass distributes its speed in space and time or spacetime. A photon gives all of it's speed to space and none to time so it moves through space at c or the speed of light because after reading your asinine posts, you might think c is for cookie.

You don't even understand the basics. When I say zero energy when talking about a classical harmonic oscillator, I'm talking about zero energy to move the pendulum when it reaches it's lowest energy state. With a quantum harmonic oscillator the pendulum never stops moving and it's never at zero energy because of energy from the vacuum.

A classical object at it's lowest energy state is at zero energy and at rest is only moving through time. It takes energy to move a classical object through space and when you do time slows down. This is called time dialation.

It's sad that I have to go over High School Science because you don't understand the basics. When I talked about harmonic oscillators anyone with a modicum of basic scientific knowledge would know that I'm talking about motion for a classical and quantum system.

a reply to: neoholographic

Neo, it is sad that your rude manners destroyed any opportunity of having a fruitful exchange of ideas. As for me, this thread is definitely dead. You turned it into a monologue. However, I forgive you.

originally posted by: Direne
a reply to: neoholographic

Neo, it is sad that your rude manners destroyed any opportunity of having a fruitful exchange of ideas. As for me, this thread is definitely dead. You turned it into a monologue. However, I forgive you.

Rude manners?

First, you don't have a clue about the subject matter so I have to spend time correcting you on basic scientific subjects. When you can't debate, you resort to being rude and name calling. You said:

Space, neo? Are you refering to spacetime? I tell you so because nobody ever talks about space as you call it. There is no space. There is spacetime. The only vacuum you might possibly know is the interior of your head.

Saying something you post is asinine is just an adjective describing your post not a personal attack. You can't debate so you resort to personal attacks and you say I'm rude???

a reply to: neoholographic

Neo, we can be friends, provided we restrict ourselves to a minimal language devoid of emotions. I'll have a go. Here is my answer to your OP on whether Wigner's friend can lie.

As far as I understand it, the so-called Wigner’s friend thought experiment shows that things can become strange and weird if the observer performing an experiment (a measurement) is also observed. Let me state straight out that I do not believe observers are required at all, a view I share with other physicists. There is a debate on this particular, as you perfectly know.

Now, the first experiment on this issue was ran by the Griffith University in Brisbane. The conclusion they drew has implications for the role that consciousness might play in quantum physics. However, they do not define what consciousness is, nor do they explain the mechanism by which such a role could be played. The conclusion at which the Griffith University arrived is that their experiment calls for a replacement of quantum theory.

Three years ago, in 2018, a team from ETH Zurich published a thought experiment based on Wigner’s friend and used it to derive a new paradox. According to the paper, their setup differs from that of the Brisbane team, though this is not an issue. Their experiment involves four observers, and the measurements they carry out are also entangled. The team concluded that if the observers apply quantum laws to one another, they can end up inferring different results in the same experiment. This is the crucial result that signals there is a problem with current quantum theory. This conclusion is the team's conclusion, not mine.

My conclusion is that yes, we do have a big poblem with quantum mechanics, though this problem comes when quantum mechanics physicists invoke consciousness without telling us all what they mean by consciousness. We first need to solve the consciousness mystery before trying to use it as an explanation for the weird results of QM experiments.

That's all I have to say.

a reply to: Direne

Finally!

You said:

As far as I understand it, the so-called Wigner’s friend thought experiment shows that things can become strange and weird if the observer performing an experiment (a measurement) is also observed. Let me state straight out that I do not believe observers are required at all, a view I share with other physicists. There is a debate on this particular, as you perfectly know.

Yes, observers are required in relativity and quantum mechanics. Recent experiments support that just like time is relative to the observers reference frame so is a measurement on a quantum system . The problem is more about belief then science. You have athiest scientist like Sean Carroll who want to reduce the role of the observer but I haven't heard anyone say that observers aren't required.

An observer can be conscious or non conscious. Here's how they described observers in the recent Wigner's friend experiment:

Before we describe our experiment in which we test and indeed violate inequality (2), let us first clarify our notion of an observer. Formally, an observation is the act of extracting and storing information about an observed system. Accordingly, we define an observer as any physical system that can extract information from another system by means of some interaction and store that information in a physical memory.

Such an observer can establish facts, to which we assign the value recorded in their memory. Notably, the formalism of quantum mechanics does not make a distinction between large (even conscious) and small physical systems, which is sometimes referred to as universality. Hence, our definition covers human observers, as well as more commonly used nonconscious observers such as (classical or quantum) computers and other measurement devices—even the simplest possible ones, as long as they satisfy the above requirements. We note that the no-go theorem formulated in (5) requires observers to be “agents,” who “use” quantum theory to make predictions based on the measurement outcomes. In contrast, for the no-go theorem we tested here (4), it is sufficient that they perform a measurement and record the outcome. The enhanced capabilities required of agents were recently discussed in (13).

advances.sciencemag.org...

So of course,, humans are observers.

Humans can record the results of a measurement in our memory. In fact, this goes to the point about human observers being able to use quantum theory to make predictions on measurement outcomes and use quantum theory to describe other agents.

Human observers have awareness of consciousness and they can extract information about the state of a quantum system recorded in their memory without the need for an external agent. We can build new technologies, write books and ask what does this mean. A non conscious observer can't do this.

People talk about a measuring device carries out a measurement but it's the awareness of consciousness from human observers that design these measuring devices. We design them with the purpose of learning the quantum state of a systen.

How can the state of a quantum system be known if an conscious observer didn't make the choice to set up an experiment in a lab, design a measuring device and learn the state of the quantum system? We then publish the results so other conscious agents can conduct experiments, publish the results and other conscious agents are updated.

Here's some recent stories on this:

A quantum experiment suggests there’s no such thing as objective reality

Physicists have long suspected that quantum mechanics allows two observers to experience different, conflicting realities. Now they’ve performed the first experiment that proves it.

www.technologyreview.com...

Quantum Theory Demonstrated: Observation Affects Reality

www.sciencedaily.com...

Quantum experiment in space confirms that reality is what you make it

www.sciencemag.org...

In truth, these aren't remarkable statements. It's only a debate because atheist scientist are scared to death of consciousness.

It's obvious that humans are observers. We can interact with a quantum system by extracting information about it's state and recording that information in our memories. We then use that information to build technologies, make predictions and more. We also design the measuring devices in the lab and make the choice to set up the experiments.

When you look at the Free Will Theorem, it shows why the observers choice is important.

The Free Will Theorem

On the basis of three physical axioms, we prove that if the choice of a particular type of spin 1 experiment is not a function of the information accessible to the experimenters, then its outcome is equally not a function of the information accessible to the particles. We show that this result is robust, and deduce that neither hidden variable theories nor mechanisms of the GRW type for wave function collapse can be made relativistic. We also establish the consistency of our axioms and discuss the philosophical implications.

arxiv.org...

This brings us to the recent Wigner's Friend experiments and Carlo Rovelli's Relational Quantum Mechanics.

All physical interactions are, at bottom, quantum interactions, and must ultimately be governed by the same rules. Thus, an interaction between two particles does not, in RQM, differ fundamentally from an interaction between a particle and some "apparatus". There is no true wave collapse, in the sense in which it occurs in the Copenhagen interpretation.

Because "state" is expressed in RQM as the correlation between two systems, there can be no meaning to "self-measurement". If observer O measures system S, S's "state" is represented as a correlation between O and S. O itself cannot say anything with respect to its own "state", because its own "state" is defined only relative to another observer, O'. If the S+O compound system does not interact with any other systems, then it will possess a clearly defined state relative to O'. However, because O's measurement of S breaks its unitary evolution with respect to O, O will not be able to give a full description of the S+O system (since it can only speak of the correlation between S and itself, not its own behaviour). A complete description of the (S+O)+O' system can only be given by a further, external observer, and so forth.

Taking the model system discussed above, if O' has full information on the S+O system, it will know the Hamiltonians of both S and O, including the interaction Hamiltonian. Thus, the system will evolve entirely unitarily (without any form of collapse) relative to O', if O measures S. The only reason that O will perceive a "collapse" is because O has incomplete information on the system (specifically, O does not know its own Hamiltonian, and the interaction Hamiltonian for the measurement).

en.wikipedia.org...

In other words, a quantum measurement is relative to the reference frame of an observer.

The wave function collapses or appears to collapse for Wigner's friend in the lab. For Wigner outside of the lab, he can establish..

alternative facts and carry out an interference measurement that shows his friend in the lab hasn't carried out a measurement. When Wigner gains knowledge of his friends measurement he can no longer measure interference.

How is the system aware when an observer has or doesn't have awareness about it's state?

When Wigner isn't aware about the state that his friend in the lab measured, he can measure interference. If his friend called him and said, "Hey Wigner, I measured vertical polarization." Wigner could no longer measure interference.

This is the whole point of the Can Wigner's Friend lie thought experiment is about. How robust is this Quantum Awareness? Can Wigner's friend lie and say he measured horizontal polarization and Wigner can still measure interference?

This is important because there's no physical explanation for awareness of consciousness. It makes no sense to say awareness comes from some physical process. It's pure fantasy. What physical process caused non conscious matter to start asking why am I here? What happens after death? What does this or that mean?

A physical process is when I boiled eggs this morning and because they were hot, I got a spoon and filled up a bowl of cold water and put the boiled eggs in the cold water. Because of thermodynamics, heat from the eggs were transferred to the cold water and the water got a little warmer and my eggs got a little cooler so I can eat them.

This is a physical process. Rain, dew on the ground and particle decay are physical processes. How in the world can a physical process give rise to awareness of consciousness?

You said:

Three years ago, in 2018, a team from ETH Zurich published a thought experiment based on Wigner’s friend and used it to derive a new paradox. According to the paper, their setup differs from that of the Brisbane team, though this is not an issue. Their experiment involves four observers, and the measurements they carry out are also entangled. The team concluded that if the observers apply quantum laws to one another, they can end up inferring different results in the same experiment. This is the crucial result that signals there is a problem with current quantum theory. This conclusion is the team's conclusion, not mine.

This is Frauchiger and Renner.

Their conclusion isn't based on science. They showed that observers can measure different outcomes for the same event on occasion. They calculated this would occur around 8% of the time if QM is universal and applies to classical observers as most Physicist think.

They concluded something wrong based on their belief that measurement by one observer applies to all observers. There's no law or anything in QM that says this must be the case. It's just their belief that this must be the case.

I say it isn't the case and Frauchiger and Renner have just provided a scientific explanation for things like the Mandela Effect or what we call strange coincidences. The Mandela Effect is exactly 2 observers observing different outcomes for the same event. This happens on a classical level around 8% of the time. Spread that 8% over 7 billion people and again, you have the mandela Effect and some strange coincidences that we just explain away.

Here's an example:

Me and my Mother went to a store. She comes rushing up the isle because she saw my cousin. I was walking down the end of the isle and there was nobody there but me. My Mother was so sure she saw my cousin that we looked for her in the store. By the time we reached the register, my Mom laughed it off and said she must have been mistaken/

What if for a brief moment me and my Mother just saw 2 different outxomes for the same event?

These things happen all of the time but we just explain it away. Frauchiger and Renner showed if QM is universal on occasion classical observers will measure different outcomes for the same event. There's no reason why QM isn't universal. Maybe a theory of self collapse may be observed but for now we're putting larger and larger objects in Schrodinger cat states.

Real-Life Schrödinger’s Cats Probe the Boundary of the Quantum World

Recent experiments have put relatively large objects into quantum states, illuminating the processes by which the ordinary world emerges out of the quantum one.

“The most interesting question is if there is some fundamental size where one cannot in some sense make entanglement,” Sillanpää said. “That would mean that something else in addition to normal quantum mechanics enters the picture, and this could be, for example, collapse due to gravity.” If gravity does play a role, that might offer some hints for how to develop a theory of quantum gravity that unites the currently incompatible theories of quantum mechanics and general relativity.

That would be quite a coup for Schrödinger’s kittens. For now, they reinforce the general belief that there is nothing special about quantum behavior, beyond the fact that it spins itself into an ever more tangled cat’s cradle from which our classical web emerges. And no cat need be killed in the process.

www.quantamagazine.org...

Quantum Superposition Bridges the Classic World

Cracks have begun to show in one of quantum’s biggest controversies. The well-known Schrödinger’s cat thought experiment, which sought to illustrate the absurdity of applying quantum theory to the macro-physical world ruled by classical physics has been challenged by a recent advancement in quantum physics. An international team, led by Markus Arndt of the University of Vienna, successfully placed a large molecule of 2,000 atoms—the biggest object yet—into a state of quantum superposition. The advancement shows that quantum effects can be translated into the classical world, establishing the foundations for scientists to continue to demonstrate how the gap between these seemingly disparate worlds might be reconciled.

projectqsydney.com...

The door is closing on self collapse theories and maybe quantum gravity.

originally posted by: neoholographic
Quantum erasing the memory of Wigner's friend

We propose a simple single-photon interferometric setup implementing their scenario, and use our reformulation to shed a new light on the assumptions leading to their paradox. From our description, we argue that the three apparently incompatible properties used to question the consistency of quantum mechanics correspond to two logically distinct contexts:

Wigner's friend is destroying the notion of materialism once again and posing serious questions about the role of the observer, consciousness and is there really an objective reality.

Sabine Hossenfelder agrees that there are problems with the internal consistency of quantum mechanics. However she disagrees that those inconsistencies mean what some people claim they mean. I made a thread about that here:

Has quantum mechanics proved that reality does not exist?
Dr. Hossenfelder says: "But of course an interaction with a single photon doesn’t constitute a measurement. We already know this experimentally. A measurement requires an apparatus big enough to cause decoherence. If you claim that a single photon is an observer who make a measurement, that’s not just a fanciful interpretation, that’s nonsense." So she's not really sold on these claims about using single photons as "observers".

Damn i shouldnt have posted this post. My bad.