My Shared History Interpretation of Quantum Mechanics

Shared history interpretation of quantum mechanics

by neoholographic

In this paper, I will propose a shared history interpretation of Quantum Mechanics. This shared history is built around consciousness and a real but non physical wave function. I will use recent studies pertaining to Wigner’s Friend and and quantum cryptography to show why a shared history interpretation of quantum mechanics bridges the gap between Copenhagen and many worlds interpretations. A shared history interpretation of Quantum Mechanics is the only interpretation that has concrete evidence to support it because it depends on the wave function being real but non physical which is supported by recent experiments in quantum cryptography.

1. Introduction

You often hear this debate about the role of the observer in Quantum Mechanics. How you view this role usually dictates the interpretation you prefer. If it's Copenhagen, then the observer is more robust and plays a crucial role in wave function collapse. If it's Many Worlds, then the observer is no different than a rock as Sean Carroll says and there's no wave function collapse. It all depends on how you view the observer in quantum mechanics. I will show through the recent paper titled,”Experimental test of local observer independence,”(1) that a conscious observer is needed to collapse many histories into a single shared history between conscious observers. This experiment was a realization of Wigner’s Friend gedanken experiment. It showed how two observers can reach different conclusions based on the same event and they can both be certain that their results are correct.

I will also show how consciousness is connected to a real but non physical wave function. This was put forth in a paper titled,”The wave-function is real but nonphysical: A view from counterfactual quantum cryptography.”(2) Transfer of information without the transmission of a physical particle was realized in a recent experiment and published in a paper titled,”Direct counterfactual communication via quantum Zeno effect.”(3)

2. Wigner’s Friend

Wigner’s original thought experiment begins with a single polarized photon that, when measured, can have either a horizontal polarization or a vertical polarization. But before the measurement, the photon is in superposition according to the laws of quantum mechanics and can exist in both states at the same time. Wigner imagined a friend in a lab measuring the state of this photon and storing the result. Wigner observed from outside of the lab so he didn’t know the results. So Wigner doesn’t have any information about his friend’s measurement. Wigner can then carry out a interference experiment on the same photon, and come to the opposite conclusion that his friend hasn’t carried out a measurement in the lab yet. So Wigner and his friend can come to opposite facts about the same event. Wigner’s friend can even call Wigner from the lab and tell him that he carried out a measurement and as long as he doesn’t tell him the results of that measurement, Wigner can still carry out a successful interference experiment. If Wigner’s Friend tells him the results of the measurement, Wigner’s wave function collapses and he can no longer get an interference pattern and his measurement is now aligned with his friend’s. It’s like Wigner’s wave function was updated when he got the results from his friend and now they have a shared history.

3. Wave Function real but non physical

The wave function being real but non physical is supported by the evidence. It also bridges the gap between Copenhagen and Many Worlds interpretations of Quantum Mechanics. Each side just has to give a little. With Copenhagen, you would have to accept that the wave function is real. With Many Worlds, you would have to accept the fact that the wave function is non physical. The first paper I will quote that supports this is titled,”The wave-function is real but nonphysical: A view from counterfactual quantum Cryptography.” referenced as number(2) in the Introduction. Here’s the Abstract from the paper.

Counterfactual quantum cryptography (CQC) is used here as a tool to assess the status of the quantum state: Is it real/ontic (an objective state of Nature) or epistemic (a state of the observer’s knowledge)? In contrast to recent approaches to wave function ontology, that are based on realist models of quantum theory, here we recast the question as a problem of communication between a sender (Bob), who uses interaction-free measurements, and a receiver (Alice), who observes an interference pattern in a Mach-Zehnder set-up. An advantage of our approach is that it allows us to define the concept of “physical”, apart from “real”. In instances of counterfactual quantum communication, reality is ascribed to the interaction-freely measured wave function (ψ) because Alice deterministically infers Bob’s measurement. On the other hand, ψ does not correspond to the physical transmission of a particle because it produced no detection on Bob’s apparatus. We therefore conclude that the wave function in this case (and by extension, generally) is real, but not physical. Characteristically for classical phenomena, the reality and physicality of objects are equivalent, whereas for quantum phenomena, the former is strictly weaker. As a concrete application of this idea, the nonphysical reality of the wavefunction is shown to be the basic nonclassical phenomenon that underlies the security of CQC.(2)

There was another test that showed that information can be transferred between two points without the transmission of a particle. The information was transferred on the phase of the wave function. Here’s the Abstract from a paper titled,”Direct counterfactual communication via quantum Zeno effect.” which is reference(3) in the Introduction.

Intuition from our everyday lives gives rise to the belief that information exchanged between remote parties is carried by physical particles. Surprisingly, in a recent theoretical study [Salih H, Li ZH, Al-Amri M, Zubairy MS (2013) Phys Rev Lett 110:170502], quantum mechanics was found to allow for communication, even without the actual transmission of physical particles. From the viewpoint of communication, this mystery stems from a (nonintuitive) fundamental concept in quantum mechanics—wave-particle duality. All particles can be described fully by wave functions. To determine whether light appears in a channel, one refers to the amplitude of its wave function. However, in counterfactual communication, information is carried by the phase part of the wave function. Using a single-photon source, we experimentally demonstrate the counterfactual communication and successfully transfer a monochrome bitmap from one location to another by using a nested version of the quantum Zeno effect.(3)

4. Shared History Interpretation

What does the shared interpretation of Quantum Mechanics say?

Consciousness is needed for observers to have a shared history. This is because only conscious observers can tell which measurement occurred and which one didn’t. When it shares this information with another conscious observer, there’s a Bayesian updating that occurs and the wave function for both observers is in sync.

CONTD

The Wigner’s Friend experiment shows that non conscious observers can cause a measurement to occur but a non conscious observer doesn’t know which measurement occurred. A non conscious observer has stored information about the quantum system vs. dynamic information.

Stored information - A measuring apparatus can store information like which slit did the particle pass through in the double slit experiment. This is stored in the memory of a non conscious observer. You need a conscious observer to come in and read the information. It can’t pass the information to another non conscious observer and the two non conscious couldn’t know which measured state they’re in vs. which measurement didn’t occur.

Dynamic information - A conscious human observer can store information about a quantum system and think about that information in abstract ways. We can say, the measurement is in this state but not in the other state. We can share that information with other conscious observers. We can write books about the information, publish papers and ponder about what it means.

Non conscious observers can reach different conclusions about the same event as shown in the Wigner’s Friend experiment. Wigner’s friend has collapsed the wave function locally and inside the lab he carries out a polarization measurement and the result is the photon is in the vertical or horizontal basis. He records this result. Wigner outside of the lab can carry out an interference measurement on the photon and his friends record and surprisingly they’re in superposition and Wigner can conclude that his friend didn’t carry out a measurement. Wigner’s friend can even call him and say he carried out a measurement and Wigner will still get an interference pattern as long as his friend doesn’t tell him the results.

This is where a shared history interpretation comes into clear view. A non conscious observer doesn't know what state it’s in. The conscious observer can tell whether you're in state |→⟩ or |←⟩ a measurement from a non conscious observer can’t. When Wigner’s friend calls up Wigner and tells him the results, the results are now recorded in Wigner’s memory and he can no longer get an interference pattern. Wigner and his friend now have a shared history. You can’t collapse different histories into a shared history without a conscious observer that can say the system is in state |→⟩ or |←⟩. Now Wigner and his friend have a shared history. Wigner can say me and my friend share a history where my friend measured the photon in vertical polarization at 1:42 P.M on a Thursday. When Wigner’s friend shares the result of his measurement with Wigner, this knowledge collapses the wave function into a single shared history and Wigner can no longer get an interference pattern. With non conscious observers, you can have different outcomes for the same event. Non conscious observers can’t tell which state the system was or wasn’t measured in and can’t relay that information to another non conscious observer thereby collapsing the wave function into a single shared history and can’t think about the measured state in an abstract way. You need conscious human observers to do these things.

Here’s another example. Let’s look at John Wheeler’s delayed choice experiment. Wheeler gave an example as to how this would look on a cosmic scale. He said:

1. A distant star emits a photon many billions of years ago.

2. The photon must pass a dense galaxy (or black hole) directly in its path toward earth.

"Gravitational lensing" predicted by general relativity (and well verified) will make the light bend around the galaxy or black hole. The same photon can, therefore, take either of two paths around the galaxy and still reach earth. It can take the left path and bend back toward earth; or it can take the right path and bend back toward earth. Bending around the left side is the experimental equivalent of going through the left slit of a barrier; bending around the right side is the equivalent of going through the right slit.

3. The photon continues for a very long time (perhaps a few more billion years) on its way toward earth.

4. On earth (many billions of years later), an astronomer chooses to use a screen type of light projector, encompassing both sides of the intervening and the surrounding space without focusing or distinguishing among regions. The photon will land somewhere along the field of focus without our astronomer being able to tell which side of the galaxy/black hole the photon passed, left or right. So the distribution pattern of the photon (even of a single photon, but easily recognizable after a lot of photons are collected) will be an interference pattern.

5. Alternatively, based on what she had for breakfast, our astronomer might choose to use a binocular apparatus, with one side of the binoculars (one telescope) focused exclusively on the left side of the intervening galaxy, and the other side focussed exclusively on the right side of the intervening galaxy. In that case the "pattern" will be a clump of photons at one side, and a clump of photons at the other side.

Now, for many billions of years the photon is in transit in region 3. Yet we can choose (many billions of years later) which experimental set up to employ, the single wide-focus, or the two narrowly focused instruments.(4)

This has been confirmed in both delayed choice experiments and delayed choice quantum eraser experiments.(5)

CONT'D

The dense galaxy or black hole acts as a non conscious observer. What it shows is that without the knowledge of a conscious observer, the measurement doesn’t become an objective shared history. The conscious observer on earth can choose how they want to measure the photon and if they want to get an interference pattern billions of years after the photon has made a choice to go to around the left or right side of the dense galaxy.

Let’s take this a step further. Let’s say a conscious observer was on this dense galaxy and he measured the path the photon took. Would this change the choices the conscious observer can make to measure the photon? No, he still has a choice of how to carry out a measurement of the photon and he can still get an interference pattern. Now imagine if the observer on the dense galaxy had a hypothetical instant communication entanglement device. The conscious observer on the edge of the dense galaxy instantly relay’s to the conscious observer on earth the result of his measurement. The conscious observer’s choices on earth are gone. He can no longer get an interference pattern because he has knowledge of the results of the measurement

This is why the wave function needs to be real but non physical as shown in recent quantum cryptography experiments. This means the wave function is real and goes through the double slits and there’s no need to assume that a physical particle is the source of interference. Quantum Field Theory tells us that particles don’t exist and they’re just excitations of underlying quantum fields. The wave function could tell us what part of the field which is more likely to be excited when you carry out a measurement and that’s where you will find the particle. Here’s some key points from the paper ,”The wave-function is real but nonphysical: A view from counterfactual quantum Cryptography.” referenced as number(2) in the Introduction.

Of course, the status of the wave function (as being real or epistemic) does not depend on Bob’s choice of AB or FB. Nor does it depend on whether Bob is located at the end of arm a or b. What may conclude is that the each of the superposed states in Eq. (1), ψa ≡ a † |0, 0i and ψb ≡ b † |0, 0i, is by itself real-nonphysical, and thus, so too the particle state state |Ψi = √ 1 2 (ψa + ψb) in Eq. (1) is also real-nonphysical. We may therefore conclude that the quantum state is quite generally real-nonphysical. In retrospect, we may reflect in this new light on the wisdom of Feynman’s observation with regard to the double-slit experiment, mentioned in the opening paragraph. Our approach suggests that in the production of fringes in the double-slit experiment, there is indeed some “real stuff” travelling down both slits, but it is not physical. This explication thus puts (or so we hope!) a name on the mystery alluded to by Feynman.

Our work showed that the non-physical reality of the wave function is not an abstruse philosophical notion, but has the concrete application of being responsible for security in CQC. Finally, we venture that it is the lack of distinction in the literature between the real and the physical aspect that is responsible for the historical difficulty in interpreting the physical significance of the quantum state. In the discussion pertaining to the double-slit experiment, at first one has the intuitive feeling that there is something real traveling down both slits. One then subconsciously maps this real thing to something physical. But clearly the possibility of the quantum wave as a physical entity is one that we would consciously reject. Thus, psychologically speaking, a person thinking about quantum foundations is caught in the perpetual dilemma of deciding whether or not the quantum state is real. It is our belief that our work resolves this dilemma.(2)

5. Conclusion

The shared history interpretation is the only interpretation with clear and convincing evidence. It shows non conscious observers can cause a measurement to occur but you need human, conscious observers to know what state did or didn’t occur and collapse many histories into a single history. This is because a conscious observer can share the results of a measurement with other conscious observers. Non conscious observers can’t do this and they can get different outcomes for the same event. There’s no way a non conscious observer can know what history they’re in or share that information with another non conscious observer. This is stored information vs. dynamic information where human consciousness can think about this information in abstract ways.

Wigner’s friend in the lab can carry out a polarization measurement and record the outcome. Wigner outside the lab can do an interference measurement on his friend’s photon that was measured and the photon where the memory of the results were stored and get an interference pattern that tells Wigner his friend hasn’t carried out a measurement. If Wigner’s friend calls Wigner with and tells him the result then this collapses the wave function into a single shared history between Wigner and his friend. This can only happen with conscious observers because conscious observers know which state the measurement is in. The only reason Wigner can get an interference pattern is because of his lack of knowledge of the outcome of a measurement on the quantum system. A non conscious observer will always have a lack of knowledge as to what state the particle is in after measurement. It will just have stored knowledge. So if two non conscious observers has stored two different outcomes for a single event, one of the non conscious observers can’t call the other non conscious observer and say this is the state that was measured thereby collapsing the wave function and being in a shared history with the other non conscious observer. This can only happen with consciousness. So a shared history interpretation of Quantum Mechanics shows consciousness is needed in QM.

References

1. advances.sciencemag.org...

2. arxiv.org...

3. www.pnas.org...

4. www.bottomlayer.com...

5. en.wikipedia.org...

Wow....

From dark to light, bye-bye corruption...

Just wow

Sincerely NC