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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Does Quantum Collapse occur? [on hold]

Collapses, Quantum Jumps, and the Born interpretation. In my mind they are all the same. But some serious physicists (Schlosshauer, for example) claim there is no evidence for the existence of ...
6
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3answers
124 views

How to understand the motion of a particle in Quantum Mechanics?

In Classical Mechanics when we talk about the motion of a particle it is the same as talking about the idea of trajectory. The fact is that in Classical Mechanics, a particle has a definite position ...
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0answers
33 views

A real 'two line' (non-interference pattern) when observed

I have seen many interference patterns from double slit experiments but I have never seen a real 'two line' pattern when observed. Does this actually exist or is it only a conclusion? if there is an ...
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0answers
59 views

Using the double slit experiment to prove or disprove the de Broglie-Bohm pilot wave theory

Probably a dumb question... If you have a double slit experiment with a second experiment (single or double slit) at 90 degrees intersecting the path of the first experiment, would the interference ...
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3answers
83 views

Does Bell's theorem exclude local hidden variables as explanation for radioactive decay?

Often it is said that Bell's theorem (and the observed violations thereof) rules out local hidden variable theories as the explanation for the seeming non-determinism found in quantum mechanics. I'm ...
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0answers
48 views

Can string theory and the Penrose interpretation coexist?

Is it possible for string theory to coexist with the Penrose interpretation of quantum mechanics? Does string theory require the many worlds interpretation?
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1answer
25 views

What trajectory do particles follow in the two-slit experiment in Bohm-de Broglie theory

In Bohm de Broglie interpretation of QM particles have trajectories; in the classic two-slit experiment what trajectories do they follow, and how is the interferance pattern interpreted? Are ...
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1answer
80 views

Does QFT prevent preparation of an entangled particle pair as in EPR experiment?

This is the claim Tommasini makes in Reality, Measurement and Locality in Quantum Field Theory:"Two spin $1/2$ particles, A and B, are created in coincidence in a spin-singlet state, and are detected ...
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0answers
20 views

Can the rate of branching in the many worlds interpretation be influenced?

If I understand correctly, in the many worlds interpretation, worlds branch when irreversible interactions occur, and that these interactions occur on very low-levels. Since they occur on such low ...
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0answers
128 views

What is the Copenhagen interpretation of quantum field theory?

I am most interested in interpretational differences due to the fact that quantum field theory is relativistic while quantum mechanics is not. By "Copenhagen interpretation" I mean a minimal ...
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1answer
45 views

Quantum force and classical limit

Today my physicist friend told me about Bohmian mechanics as an alternative way of looking at QM. He told me that in Bohmian mechanics the wave function gives rise to another fundamental force (the ...
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2answers
866 views

Which theory explains the path of a photon in Young's double-slit experiment?

In Young's double-slit experiment, we know that a photon goes through either one of the slits but we don't know which one, and it ends up on a screen. I want to know which theory can predict to the ...
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3answers
475 views

Why doesn't Many-Worlds interpretation talk about many worlds?

I was reading this interpretation from this site, where these lines are noteworthy enough to talk for the fact that this interpretation doesn't actually talk about many-worlds: These are the "many ...
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0answers
38 views

Mathematical formalism for the Many World's Interpretation of Quantum Mechanics

A short question: is there a mathematical formalism underlying the Many Worlds Interpretation, that is published in the literature, in much the same way, but on a presumably smaller scale, as String ...
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2answers
105 views

Does the many worlds interpretation eliminate the spooky action at a distance paradox? [closed]

I'm sorry if this is a stupid question. I'm a novice at physics. I have read the article about entanglement and EPR paradox. The spin of two particles is measured when they are very far apart, and ...
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1answer
46 views

Particle position and speed [duplicate]

If I understand correctly, particle is something at a point of time, where you can tell it's position, but what if particle is moving, then you can tell it's speed. From what I understand wave is NOT ...
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2answers
61 views

Spectral lines on a detector

How can it be possible for a single electron to go through 2 slits at the same time and create 2 spectral lines on a detector. What is wrong with that theory, but at the same time produce results as ...
2
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1answer
134 views

Flaws of Broglie–Bohm pilot wave theory?

I recently learned about an oil drop experiment that showed how a classical object can produce quantum like behavior because its assisted by a pilot wave. How has this not gained more attention? What ...
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1answer
111 views

Does quantum theory obey locality?

Bell's inequality together with the Aspect experiment shows that that we cannot have local realism. But does quantum theory obey locality? and if not how can locality be violated but not special ...
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4answers
182 views

What really is a particle?

In Classical Mechanics we consider particles as things whose internal structure for the purpose of studying some phenomenon might be neglected. In that setting we associate particles to points and ...
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4answers
193 views

Does quantum mechanics imply that particles have no trajectories?

In Classical Mechanics we describe the evolution of a particle giving its trajectory. This is quite natural because it seems a particle must be somewhere and must have some state of motion. In Quantum ...
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2answers
120 views

How does this youtube video demonstrate quantum entanglement? [closed]

The following is an experiment that shows "spooky action at a distance" of quantum entanglement; that is, when we measure some properties of two entangled photons, we find that measuring property of ...
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0answers
59 views

Are there any event-based interpretations of quantum physics? [closed]

Are there any interpretations of quantum physics where we have a combination of probabilities and objective realizations of these probabilities on a very low level. The first part of my question is ...
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0answers
57 views

Interpretations of Quantum Mechanics and Locality

I have read these posts here: Why do people still talk about bohmian mechanics/hidden variables Disproof of Bell’s Theorem What combinations of realism, non-locality, and contextuality are ruled ...
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0answers
26 views

Entanglement and the boundaries of fiction

If entanglement is just a correlation from when the particles were in proximity, and there is no causality between the two, can the state of one particle be changed after being measured, and that ...
3
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3answers
103 views

Physical meaning of quantum interpretations [closed]

Do interpretations of quantum mechanics have physical meaning? An argument for no would be the fact that no matter the interpretation, one gets the same measurements. They also do not follow logical ...
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1answer
48 views

If the only observer dies, could observer 2 ever have see a different result?

My layman's understanding of QFT is that once a system is observed, any future observation will always yield the same result. Would this hold true if the original-and-only observer, without any ...
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0answers
72 views

What does Bell's theorem rule out?

What exactly did Bell's theorem rule out? Did it rule out "locality", so we must give up and think of Copenhagen or maybe some realism theories (Bohmian for example)? ... That's how I understand ...
3
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1answer
220 views

Has this experiment really demonstrated wave-function collapse?

My question is: why did the following experiment claim that it had demonstrated the wave-function collapse? http://www.nature.com/ncomms/2015/150324/ncomms7665/full/ncomms7665.html I would have no ...
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1answer
54 views

Relational Interpretation of Quantum Mechanics and Universal Wave Function

Why is there no universal wave function for a relational interpretation of quantum mechanics? "Quantum mechanics is a theory about the physical description of physical systems relative to other ...
0
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1answer
58 views

Are The Quantum Assumptions of MBT Theory Correct?

I've become very interested in Tom Campbell's MBT Theory (Plenty of YouTube videos). I can't explain it all here because it takes a book (The one he's written). It's based on the virtual reality ...
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1answer
103 views

Immortality within the multiple worlds interpretation of quantum mechanics [closed]

I understand the multiple worlds interpretation of quantum mechanics as follows: Any time an event happens, all of the possible outcomes take place ("split the universe") If I then think about a ...
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2answers
102 views

multiverse fabric of reality

Source-"fabric of reality"- author d. deutsch - his contention, as I understand it, is that quantum interference is caused by "almost, but not identical quite quantum entities" , e.g. electrons, from ...
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1answer
66 views

Are there nonlinear models of quantum mechanics which forbid superluminal signaling?

What would a nonlinear model of quantum mechanics which forbids superluminal signaling look like? Of course, a nonlinear $\psi$-ontic theory with entangled states could have superluminal effects upon ...
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2answers
68 views

Books on Quantum Measurement

I have been trying to understand clearly the concept of non locality, hidden variables, quantum measurement etc through research papers. I also read Quantum Theory and measurment by Wheeler and Zurek ...
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0answers
39 views

How can a spinor represent an “epistemic” state?

I have read a lot of stuff on the seemingly endless debate on ontology/epistemology of the quantum state $\psi$. But I always wonder: how can a spinor be considered epistemic when $\psi$ really ...
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0answers
20 views

Does quantum complementarity inherently require ensembles?

If there are two complementary observables, $P$ and $Q$, it does superficially appear as if the only kind of empirical evidence we can get for complementarity has to come from statistical data from an ...
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3answers
188 views

How do probabilities emerge in the many-worlds interpretation?

My understanding is that at each quantized unit of time that a split occurs, every possible recombination of particles occurs in the 'objective' universe. If this is the case, what relevance to ...
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0answers
52 views

finetuned quantum experiments by Murch lab, do any have dynamics outside of basic QM formalism/ axioms?

a series of very finetuned quantum experiments have been reported by the Murch lab eg in 2 articles in Nature & analysis there,[1][2][3] some leading to dramatic accounts in the media.[4] do ...
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2answers
143 views

Does Bell's theorem rule out the possiblity that measurements are completely determined by events in the past light cone?

I'm studying Bell's theorem and the CHSH inequality for some time. Now it's clear to me that one cannot reproduce the correlations predicted by quantum mechanics by assuming that particles carry ...
92
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3answers
15k views

How come some people are claiming that the Big Bang never happened?

A news story is going viral on social media networks claiming that two physicists have found a way to eliminate the Big Bang singularity, or in layman's terms (as claimed by many sensationalist news ...
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3answers
439 views

Can existing quantum computers be considered evidence for parallel universes?

In this video ( http://www.youtube.com/watch?v=bJpIclDmi2M ) Max Tegmark , a MIT cosmologist says that if we build a quantum computing successfully it will be a evidence that Parallel Universes ...
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9answers
2k views

“Reality” of EM waves vs. wavefunction of individual photons - why not treat the wave function as equally “Real”?

In thinking how to ask this question (somewhat) succinctly, I keep coming back to a Microwave Oven. A Microwave Oven has a grid of holes over the window specifically designed to be smaller in ...
3
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0answers
127 views

Is it possible to travel between worlds in the many worlds interpretation of quantum theory? [closed]

In the Many Worlds Interpretation (MWI) of quantum mechanics, all possible outcomes of a measurement occur, and each possible outcome corresponds to a distinct "world" or universe. Is it possible to ...
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3answers
333 views

How does De Broglie–Bohm theory or pilot wave theory explain the results of the Stern–Gerlach experiment?

The Copehagen interpretation of QM explains the Stern–Gerlach experiment by asserting that a particle is in a superposition of states and doesn't have a definite spin until measured. However, the de ...
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1answer
157 views

What is the significance of Planck's constant in De Broglie–Bohm theory or Pilot-wave theory?

In standard QM, Planck's constant seems to be a constant that describes the smallest quanta of energy in some way. Does De Broglie–Bohm theory have an alternate interpretation of that constant and ...
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0answers
42 views

Born-like measuring rule in classical experiments

this 2011 paper "Born's rule from measurements of classical signals by threshold detectors which are properly calibrated" by Khrennikov investigates the theoretical possibility of Born-like ...
4
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1answer
148 views

What specifically is incorrect about the Dirac Sea interpretation?

So taking the square root of $E^2 = (m_oc^2)^2 + p^2c^2$ yields two solutions. The Dirac Sea treats the negative solution as an infinite space of electrons with negative energy. All the observable ...
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1answer
45 views

Bypassing complementarity with cumulative weak measurements?

Consider the standard double slit experiment with one photon at a time. Now, replace the photographic plate (or fine resolution single photon detector screen) with a converging lens, and move the ...
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2answers
141 views

What does density operator being same for two sytems tells us?

Yesterday I asked a question. I got it that if a density operator is given as $$\rho=\sum_{i=1}^{i=k}p_i|\psi_i\rangle \langle\psi_i| \tag{1}$$ then it means that the system is one of the states ...