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Questions tagged [quantum-interpretations]

This tag is for questions relating to what, if anything, the quantum mechanical formalism and experimental results say about the way the world works.

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Have there been any papers on a relativistic relative state (“MWI”) interpretation of QM with continuous spectra?

I've read the original papers on the relative state interpretation ("MWI") of Quantum Mechanics. They seem compelling, but they only addressed a nonrelativistic system and operators with discrete ...
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Doubt about the probabilistic nature of quantum stuff and the field theory

To the quantum field theory, is it like there's "two layers of reality", one in which things are just probabilities waves that collapses into the quantum fields or is the quantum field and its waves ...
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How fundamental is the uncertainty relation? [duplicate]

I was having a discussion over the uncertainty relation with some with of my friends with people splitting over the nature of uncertainty relation. So there were two groups formed (a) One of the ...
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4answers
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How to interpret this construction of the states in QFT?

Non-Relativistic Quantum Mechanics To make this question clear it might be useful to contrast with non-relativistic quantum mechanics. In any quantum theory, the states of a system are unit rays in ...
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1answer
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Energy in Many-Worlds Interpretation

A few answers on here seem to suggest to something like the following: In the Many Worlds Interpretation, the amplitude of a branch exponentially decreases over time and so the energy of that branch ...
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Is many-worlds interpretation only a philosophical matter?

Is many-worlds interpretation only a philosophical matter? It seems to me that we can't exclude a possible test for this hypothesis. I explain. For superposition principle each world would follow the ...
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Does something prevent superposition at our scale?

I often encounter the argument that quantum mechanics reduces to classical mechanics at sufficiently big scales, as soon as h becomes sufficiently small respect to the actions involved. I clearly ...
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Are superposition and uncertainty principles logically dependent?

If we assume superposition and define an Hilbert space with canonical commutation relations we can derive uncertainty relations. So it seems the uncertainty principle isn't required, or should be ...
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Why is wave-function collapse still being taught in quantum mechanics? [closed]

I don't really understand why wave-function collapse is still being taught while we seem to have better interpretations of QM available nowadays. During the early development of quantum mechanics the ...
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Can quantum randomness be somehow explained by classical uncertainty? [closed]

In quantum mechanics, the outcome of each measurement is random, distributed according to the squared amplitude of the wave function obtained from the Schrodinger's equation. Now, can someone suggest ...
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5answers
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Conceptual understanding of operators in QM

Do operators in QM represent in some fashion the action of the measurement apparatus on a state being measured? Usually operators in QM are introduced as abstract transformations whose eigenvectors/...
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1answer
114 views

Does Bell's theorem imply nonlocality using a false assumption?

In https://arxiv.org/abs/1409.5158, the author concludes that Bell tests cannot refute local realism, because they employ a wrong analysis. He says: "The quantum joint prediction cannot be ...
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Commutator $\vec{L}$ with $\vec{X}\cdot\vec{P}$

Let $\vec{X}=(X_1,X_2,X_3)^T$ and $\vec{P}=(P_1,P_2,P_3)^T$. Define $\vec{L}=\vec{X}\times\vec{P}$. Then, I can calculate $\vec{L}=(X_2P_3-X_3P_2,\,X_3P_2-X_2P_3,\,X_1P_2-P_1X_2)^t$. For all ...
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1answer
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What is the reason for the reported opposite-of-QM handedness of photons in a Bell test with circularly polarized photons?

In https://file.scirp.org/pdf/OPJ_2016111414355792.pdf, a Bell test using circularly-polarized photons is reported. The data shows that coincidences happen in the reverse handedness predicted by ...
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2answers
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Are all Bell tests valid only for linearly-polarized photons? [duplicate]

In https://arxiv.org/abs/1407.2605, it is argued that all photons are necessarily circularly polarized, and linearly-polarized photons must be a superposition of such circularly-polarized photons. ...
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1answer
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Why does superposition principle and Copenhagen interpretation not contradict with themselves?

In quantum mechanics, when we say that a particle in a state $|x_1\rangle$, physically the states $|x_1 \rangle $ and $c |x_1\rangle$ (for some $c\not = 0\in \mathbb{C}$) are the same, i.e they ...
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How could quantum effects occur in the early universe without an observer?

In inflationary cosmology, primordial quantum fluctuations in the process of inflation are considered responsible for the asymmetry and lumpiness of the universe that was shaped. However, according to ...
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How do we know that entanglement allows measurement to instantly change the other particle's state? [duplicate]

I have never found experimental evidence that measuring one entangled particle causes the state of the other entangled particle to change, rather than just being revealed. Using the spin up spin down ...
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3answers
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Observer in Many Worlds Interpretation [duplicate]

Something has been bothering me about the Many Worlds Interpretation. Proponents of it (e.g. Sean Carroll) often claim that it does away with the observer, or at least the paradox-inducing status the ...
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Safer version of quantum suicide?

Quantum suicide imagines a gun which will shoot a person in a box, and this gun is rigged up to the release of radioactive decay which has a quantum probability of 50% chance of decaying or not ...
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1answer
130 views

How does the Many-Worlds Interpretation of Quantum Physics relate to Consciousness? [closed]

According to the Many-Worlds Interpretation of Quantum Mechanics, each quantum event causes the world to "branch" into a superposition of outcomes. How come "my" consciousness only chooses one of ...
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2answers
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Can we have an arbitrary set of trajectories in Bohmian mechanics?

In Bohmian mechanics, the initial configurations and the pilot wave determine the future of the system. Given a set of initial positions for particles and a set of arbitrary trajectories, can we ...
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1answer
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How did Big Bang determine the initial conditions of the universe?

My question is that how did the Big Bang determine the initial distribution of the particles and their wavefunctions? In theories like Bohmian mechanics or Many worlds, how was the universal ...
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1answer
108 views

Bell inequality as a game: Why is it impossible to always win?

Another Bell's Theorem Question I am trying to follow the simple model of Bell's Theorem outlined in this paper: https://people.eecs.berkeley.edu/~vazirani/s07quantum/notes/lecture1.pdf. Please read ...
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Does retro-causality imply unpredictability?

In some interpretations of Quantum mechanics (e.g. transactional interpretation), the future affects present. Is this a source of unpredictability in such interpretations, which makes them have the ...
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Many World's Hypothesis [closed]

According to the Many Worlds interpretation of quantum mechanics by Hugh Everett, taking the double slit experiment as an example, every possible outcome that can happen does happen. And the chances ...
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The Many-Worlds interpretation of Quantum Mechanics [duplicate]

How does the Many-Worlds interpretation really work conceptually? Very often I hear something like: When a decision is made, there is this splitting of the Universes. Each outcome happens but each in ...
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3answers
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Does the various interpretation of quantum mechanics have any impact on how we interpret quantum field theory?

Does the various interpretation of quantum mechanics have any impact on how we interpret quantum field theory? Or can QFT be considered as one of the interpretation of QM, I mean the later case as in ...
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1answer
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How acts a Double slit with a clock?

We have the simple arrangement of the double slit, but with the addition of a precise clock. The screen is also substituted by a CCD camera, so one can check when there is an event (hitting of the ...
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Does Lucien Hardy's “Paradox” show that all realist interpretations of quantum mechanics cannot be made lorentz invariant?

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.68.2981 Reading the abstract he claims that if a realist interpretation claims to be lorentz invariant, it produces the wrong predictions. ...
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1answer
78 views

The many world interpretation and immortality [closed]

This question might not be appropriate as it is philosophical on a similar level as the Schrödinger's cat thought experiment. In any case it might be interesting to think about it nonetheless. The ...
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1answer
127 views

Is the Universal Wavefunction a sensible ontological concept?

It seems to me that several quantum interpretations rely on the idea that there exists a wavefunction that completely specifies the state of the universe. Of these, the Many Worlds Interpretation is ...
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Can the many worlds interpretation use the Born rule for decoherence? [closed]

If the Many-Worlds Interpretation cannot derive the Born rule does it need mind body dualism to make sense of probabilities? I asked a different question here regarding MWI and circularity. But here'...
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Would every particle in the universe not have some form of measurement occurring at any given time? [duplicate]

I know this is probably a common point of confusion, but I have a specific question about measurements in Quantum Mechanics. I read an explanation on this, but still have a point of confusion. The ...
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Is there an official list of the postulates of quantum mechanics?

Having been looking at lecture notes, online sources and books, the list of postulates of quantum mechanics seems to vary. For instance, some sources (my lecture notes, for instance) refer to $|\...
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Is photon interference really random? [closed]

I know that according to the many worlds interpretation, there is no randomness and rather there is a universal wave function that simulates an observer with a continuously branching timeline. My ...
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Information Centric Interpretation of the Delayed Choice Experiment

The photon travels from the emmitter to the detector. Along the way it bounces off a few mirrors and off or through a beam splitter or two. This journey takes time, but only from OUR perspective/frame....
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Is Bohmian mechanics wrong in the case that space and time are quantized?

Bohmian mechanics assumes that particle trajectories are continuous. Also, it claims the random outcome of certain experiments (like the double-slit experiment) to be due to the random initial ...
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1answer
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How does the “many worlds” interpretation follow from the “universal wavefunction” idea?

So, I took this class some time ago where we discussed Hugh Everett's approach to QM. The premise seemed very logical to me: Isolated systems evolve according to the Schrödinger Equation. Of course ...
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Justification for “which path” inference in Hardy's paradox?

I'm going over Hardy's paradox again recently and whenever I try to think about it I always get confused with the classical part of the analysis. Just as a brief summary, the setup of the paradox is ...
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Why are observables hermitian operators in the Everett interpretation?

Observables correspond to hermitian operators on the quantum state. But in the Everett interpretation, the wave function doesn’t collapse since we consider the entire universe as a single quantum ...
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How does the Many Worlds Interpretation define probability? [closed]

I'm not asking for any derivation. What is probability related to in the MWI? Is related to the fraction of observers that see various outcomes? Or something more objective?
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3answers
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Accessible resources for learning Bohmian mechanics? (Undergrad)

I am an undergraudate physics and math major. For context, I've taken senior level quantum 1 as well as real and complex analysis. I'd be really interested in focusing on understanding the ...
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Why do we need the third axiom of QM to explain the wave function collapse? Why don't we use the decoherence process as an axiom?

I've always seen the standard interpretation and axioms of QM as in some way tricky on a philosophical level. They state the collapse of the wave function is caused by the measurement. 3.b If $A$ ...
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1answer
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Is the Everettian interpretation the only 'realist' interpretation which has been actively researched for relativistic quantum theories? [closed]

I take it that quantum interpretations can be roughly classified into realist and instrumentalist interpretations. In the former category we have the De Broglie-Bohm interpretation, Everettian ...
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Does the Copenhagen interpretation really predict that Schrödinger's cat is both alive and dead?

Accoring to the Wikipedia article Schrödinger's cat, the answer is yes. I really don't think so. I don't think Schrödinger's cat is a good example because in fact, it's not the case that it will with ...
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How can a particle's position be random and uncertain in quantum mechanics if it is already pre-determined in relativity?

In relativity, to my knowledge, the path of an object is described by its worldline in spacetime, and since time is a part of the spacetime geometry, an object's worldline--in a sense--always exists ...
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How do we interpret the many-worlds interpretation in daily life?

Of course one can say it is futile to reason about that. But if one does could perhaps reveal a wrong understanding of the MWI. Or it could clarfy how far one can extend this interpretation. Sean ...
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Does our planet's inorganic period negate the concept of creation through observation?

How can our physical world (only) manifest itself to us through observation when we know that our planet experienced a long inorganic phase that predated organic evolution by millions of years? In ...
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Quantum mechanics in terms of density operators as the fundamental object? [duplicate]

So I've done a two courses in undergrad quantum mechanics, the first began with wave mechanics and then went on to bras and kets, the second course went more into detail regarding bras, kets, hilbert ...