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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Universal wave function

Doesn't the existence of a Universal wave function allow one to extract a preferred space time foliation? There are plenty of papers that try and derive the prefered space time foliation from BM ...
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Why doesn't Wigner's friend interact with the system?

So I was recently modelling something that turned out to be basically Wigner's friend. I saw there were some differences (in the Wiki page) in how it was modelled: Namely, that Wigner's friend ...
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1answer
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Change of basis in the many worlds interpretation?

Say we have two orthogonal states $|A\rangle$ and $|B\rangle$. In the many worlds interpretation, we can imagine two parallel universes in which we are either in state $A$ or $B$. But now if we ...
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Is the universe fundamentally deterministic?

I'm not sure if this is the right place to ask this question. I realise that this maybe a borderline philosophical question at this point in time, therefore feel free to close this question if you ...
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3answers
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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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1answer
178 views

What are the (philosophical) implications (if any) of this experiment in relation to the Bohr-Einstein debates and hidden variable theories? [duplicate]

What are the (philosophical) implications  (if any ) of this experimental result, in relation to the Bohr - Einstein debates and hidden variable theories of quantum mechanics? A related question ...
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9answers
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Where to draw the line between quantum mechanics theory and its interpretation(s)?

I've completed a full year QM course (undergraduate level) and I am left confused on where to draw the line between quantum mechanics theory and its interpretation(s). I would personally like to stick ...
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5answers
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Is the collapse of the wave function inherently time asymmetric?

Schroedinger's equation, as we all know, is time symmetric. In quantum field theory, we have to come up with a more sophisticated CPT reversal, but the essential point remains unchanged. However, the ...
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2answers
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Why do atoms interact differently? [closed]

We live in a 3-dimensional Universe, so why don't atoms (electrons) follow the same rules as humans, planets and other 3-dimensional objects? So does that mean electrons and other quantum objects pop ...
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1answer
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Is the MWI symmetric in time?

Reading the blog of Sean Carroll (I recognize he isn't the only voice) has made me more sympathetic to the notion of many worlds, but reading Susskind (also not the only voice) has made me think that ...
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2answers
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Why does the effect of measuring an entangled particle is not apparent when examining only one particle? [closed]

As far as I understand, the Bell test experiments show that observations (measurements) of entangled particles have an effect on one another. This effect is apparent when examining the results of ...
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2answers
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What counts as a measurement?

In quantum mechanics, an elementary particle does not have a well defined position until a measurement is performed on it (right?). Such a "measurement" is any sort of interaction with other ...
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8answers
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Why is the application of probability in QM fundamentally different from application of probability in other areas?

Why is the application of probability in quantum mechanics (QM) fundamentally different from its application in other areas? QM applies probability according to the same probability axioms as in other ...
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8answers
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Is the Copenhagen interpretation falsifiable?

According to the Copenhagen interpretation, physical systems generally do not have definite properties prior to being measured. The Schrödinger's cat is both dead and alive, until an observation is ...
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1answer
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Probability of finding a particle in a superposition

In QM, is it possible to ask what the probability of finding a particle in a superposition will be? Once a particle is in a superposition, it is possible to find out the probability that it will be ...
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1answer
195 views

Is it possible to reproduce the energy spectrum of quantum chaos using classical cellular automata?

Is it possible to reproduce the energy spectrum of quantum chaos using classical cellular automata? It's hardly impressive to reproduce harmonic oscillators.
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1answer
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What is the meaning of “extradistant” in this context?

This the context. In his book The Outer Limits of Reason Noson Yanofsky says: There are, however, disadvantages to hidden variables that have kept most physicists away. For example, the equations ...
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3answers
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Are bubble chamber tracks inconsistent with quantum mechanics?

I am reading the book How Is Quantum Field Theory Possible? by Sunny Auyang, and he raises an interesting point in chapter 4 (p. 23): L. E. Ballentine argued that the projection postulate leads to ...
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Why can't GRW theory be easily tested?

To me it seems that no matter if GRW theory is true, there would already be a lot of observations and evidence for/against it, since it will in quite simple situations make different predictions from ...
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3answers
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Does the Uncertainty Principle really rule out the existence of definite trajectory of electrons?

Excerpt from my textbook It is impossible to determine simultaneously, the exact position and exact momentum (or velocity) of an electron. It rules out the existence of definite trajectories ...
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2answers
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What are non-local hidden variables?

It is said that Bell's Inequality basically denies all possible local hidden variables theories as solutions to entanglement but what does a non-local hidden variable theory mean and how does it get ...
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2answers
232 views

Does the quantum eraser double slit experiment disprove many worlds interpretation?

The quantum eraser double slit experiment shows that interference pattern is destroyed not by interacting with the quantum particle, but rather by getting which path information. In this experiment ...
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1answer
520 views

Is the trajectory of a quantum particle a well defined concept and how does this depend on the interpretation of quantum mechanics?

A common statement about quantum physics is that the "trajectory" of a particle is no longer a well defined concept because of the uncertainty relations for position and momentum. If one interprets ...
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1answer
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Is the Born rule indeed wrong?

This is a question about the validity of a preprint, arXiv:quant-ph/0509089, which claims that the "Copenhagen Interpretation of QM is incorrect" (same title, authored by Guang-Liang Li and Victor O.K....
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1answer
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Interpretation of the wave function in newtonian spacetime

A Newtonian spacetime is a quintuple $(M, \mathcal{O}, \mathcal{A}, \nabla, t)$ where $(M, \mathcal{O}, \mathcal{A}, \nabla)$ is a 4 dimensional differentiable manifold with a torsion free connection, ...
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3answers
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Einselection locality in decoherence theory

Consider two polarity-wise entangled photons A and B in an EPR experiment. The process of measuring the polarization of photon A by Alice is described by the decoherence of the 2-photons system ...
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1answer
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Bosons in Bohmian mechanics

I would like to know if even bosons in the same quantum state, like in a BEC, can be discerned (by their positions) in Bohm's mechanics.
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1answer
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Why does MWI need decoherence theory and how can these models be combined?

As far as I understood decoherence theory, it explains, why we are not able to measure superposition of macroscopic objects in some specific basis, which turns out to be the position-basis in most ...
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1answer
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What's the basic ontology of QFT?

I've been studying QFT for almost a year now but am still fairly unclear on the basic ontology of the theory. Here's what I'd consider the "basic ontology" of non-relativistic quantum mechanics: A ...
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1answer
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How to understand the transition amplitude in the Copenhagen interpretation

In Chapter 8 of Townsend's A Modern Approach to Quantum Mechanics, he states that the expression $\langle x', t' | x_0, t_0 \rangle$ gives the amplitude for a particle that is at position $x_0$ to at ...
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0answers
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Scan Quantum mechanics: Status of current research

I recently stumbled on a new interpretation of Quantum mechanics, called Scan Quantum Mechanics, given by Beatriz Gato-Rivera. She suggests a quantity called quantum inertia, which divides the ...
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1answer
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Interpreting wave-particle duality due to wave crests [closed]

I have been thinking a lot about the double slit experiment and am wondering whether any theorist has ever considered the following interpretation for wave-particle duality: Could the reason we ...
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6answers
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Is the wave function objective or subjective?

Here is a question I am curious about. Is the wave function objective or subjective, or is such a question meaningless? Conventionally, subjectivity is as follows: if a quantity is subjective then ...
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2answers
86 views

Is reality really epistemological in its complete sense?

Taking the case of Schrodinger's cat, if the measurement of the cat is not yet done, then I don't know whether the cat is dead or alive. Epistemologically speaking, since I don't know about the ...
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Loschmidt's paradox in Bohmian Mechanics

In Bohmian mechanics, the position of the particles must have a random distribution given by $\rho = |\Psi|^2$, where $\Psi$ is the wave function, in order to be compatible with Born rule in standard ...
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Why is this Pilot-wave model on a discrete spacetime is stochastic? [duplicate]

In Gluza & Kosek (2015) (DOI 10.1007/s10701-016-0026-7; paper available at Springer (NB: PDF)) It introduces a pilot-wave model on a discrete spacetime lattice. However, the pilot-wave model is ...
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1answer
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What is the physical meaning of the zeroness of the antidiagonal of the matrix representation of $\textbf{n}\cdot\textbf{S}$ operator?

I encountered a problem where I had to use $\textbf{n}\cdot{\textbf{S}}$. It was found to be: What does it mean physically, that the antidiagonal of this matrix is 0, for any $\textbf{n}$?
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1answer
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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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Measurement problem: Origin of probabilities in Many-Worlds Interpretation

As far as I can tell there appears to be an active group of academics (including the likes of Sean Carrol) who believe in the Many-Worlds Interpretation of quantum mechanics, but feel that the origin ...
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Why is the Copenhagen interpretation of quantum physics the most widely accepted one?

I've been digging a lot into quantum physics in the last few weeks. I didn't care much about the maths, just about what empirically happens to get a conceptual idea about quantum phenomena. The most ...
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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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Implication of Born's rule on the superposition principle

BACKGROUND Born's rule quantifies the interference pattern of a single quantum particle going through two possibles paths A and B as $P = |A|^2 + |B|^2 + ⟨A|B⟩ + ⟨B|A⟩$. The standard interpretation ...
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1answer
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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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Quantum Bayesianism (QBism) and the double slit experiment

How is the following experimental fact interpreted in Quantum Bayesianism (QBism)? In a double slit experiment we measure position directly after the slits. Because of that the interference pattern on ...
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1answer
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MWI universal wave function question?

In MWI, there is only one wave function in the universe ( the universal wave function). So say if I detected a particle and its wave function decoheres, since the universal wave function never ...
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10answers
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On a measurement level, is quantum mechanics a deterministic theory or a probability theory?

Quantum mechanics is a non-commutative probability theory. As such, it fundamentally behaves differently from classical probability theories. This manifests itself most pronouncedly in the uncertainty ...
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14answers
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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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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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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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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 ...