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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11
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3answers
347 views

Can someone clarify whether the recent experiment closing all remaining loopholes to Bell's Theorem really shut the door on local realism for good?

I saw this recent article on Phys.org that purports to close all remaining loopholes that previous experiments on violations of Bell's inequality left open. My question is, does this really close the ...
8
votes
4answers
697 views

Does Dirac's argument against classical mechanics stand in contradiction to Bohm's theory?

In his book on Quantum Mechanics, P.A.M. Dirac talks about the stability of the atom as a means of demonstrating the need for quantum mechanics. He writes: The necessity for a departure from ...
1
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1answer
45 views

Hydrogen atom nodes and Bohmian trajectories

Wouldn't the fact that the solutions to the hydrogen atom orbital shape have nodes prove that the Bohmian interpretation is incorrect, since in that interpretation, the electrons would have a fixed ...
0
votes
2answers
120 views

Physical quantities have definite values?

I don't really know if this question has an anwser but I thought it was worth to try asking. My point here is the following: in Quantum Mechanics, to describe the states of a system we use a Hilbert ...
-2
votes
3answers
156 views

Has the double-slit experiment been performed with animals as the observers?

As the title says, has the double-slit experiment been performed with animals (not humans) as the observers? If yes, which animal was used and what was the result?
1
vote
1answer
68 views

Is contemporary physics interpreted in an instrumentalist way? [closed]

I'm a master student in theoretical physics and the reason why I choose this career is far more related to the "philosophical beauty" of physics, than to my personal ability or skills. This, in some ...
2
votes
4answers
421 views

Is quantum physics truly random or does it just appear that way because of Heisenberg uncertainty principle

The behavior of an electron (and other tiny things) is said to be probabilistic because we can't say where an election will be when we measure it, but only where it will probably be. As I understand ...
-2
votes
1answer
86 views

Does the uncertainity principle actually attack determinism? [closed]

It's not really clear to me how does QM attacks determinism. It sure attacks computability, which is a component of newtonian, naive determinism, but it's often claimed to destroy determinism itself ...
1
vote
2answers
221 views

Does the following experiment disprove the Copenhagen interpretation?

I have a question concerning the scientific experiment proposed in the following video, (25:00-29:00) titled the "EPR Thought Experiment", which bears resemblance to the quantum eraser experiment. ...
3
votes
3answers
155 views

Where are the worlds in many-worlds interpretation?

What does it mean in MWI for other universes to exist? Are they in some sector of spacetime beyond our cosmic horizon or is it more complicated? I'm not asking this on Philosophy SE because people ...
0
votes
2answers
71 views

Terminology for “measurable” and “hidden” realms in quantum physics

Please excuse if some of my terminology is vague, the whole point of this question is to clarify terminology. In quantum physics, one frequently encounters situations where there are some kind of two ...
2
votes
0answers
63 views

Is there a video of a double-slit experiment using walking oil droplets (aka dotwaves)?

I've heard there have been experiments with walking droplets in a double-slit setup, and I've seen videos of many of the other quantum phenomenons walking droplets can emulate, but I can't find one of ...
4
votes
1answer
111 views

In interpretations of QM where the wave function is real, what does that mean?

In a lot of interpretations of Quantum Mechanics they believe that the wave function is "real". But what does that mean? Are they saying that the wave function of an elementary particle ...
-2
votes
2answers
78 views

In quantum mechanics does the truth/accuracy of a measurement really matter?

Once John Wheeler said "the past has no meaning or existence unless it exist as a record in the present". So, in a experiment of delayed choice entanglement swapping, if we used a faulty detector to ...
3
votes
4answers
154 views

What limits causality in the many-worlds interpretation (MWI)?

It's widely held that it's either very difficult or impossible to affect the outcomes of experiments in other branches of the many-worlds. The reason given is usually something along the lines that ...
2
votes
3answers
203 views

Does the Copenhagen interpretation require Nature to solve NP problems instantaneously? [closed]

Let's say we have a quantum computer with two registers taking in $m$ and $n$ qubits respectively, with $m$, $n$ suitably large. Let $f:\{0,1\}^m \rightarrow \{0,1\}^n$ be a one-way function. Set up ...
8
votes
5answers
343 views

In the oil droplet experiments that suggest de Broglie’s pilot wave theory might be accurate, what does the fluid surface correspond to?

As a particle travels to a screen, it is traveling through 3-dimensional space. In the oil droplet experiment, there are only two dimensions of any importance—the droplet merely moves along the ...
6
votes
3answers
333 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 ...
0
votes
0answers
58 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 ...
0
votes
0answers
110 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 ...
0
votes
2answers
137 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 ...
0
votes
0answers
58 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?
0
votes
1answer
41 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 ...
5
votes
1answer
149 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 ...
0
votes
0answers
25 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 ...
21
votes
2answers
749 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 ...
1
vote
1answer
56 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 ...
4
votes
2answers
951 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 ...
5
votes
3answers
718 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 ...
1
vote
0answers
41 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 ...
0
votes
2answers
180 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 ...
0
votes
1answer
68 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 ...
0
votes
2answers
66 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 ...
4
votes
1answer
1k 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 ...
1
vote
1answer
136 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 ...
3
votes
4answers
229 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 ...
4
votes
4answers
334 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 ...
-1
votes
1answer
243 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 ...
0
votes
0answers
72 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 ...
3
votes
3answers
125 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 ...
0
votes
1answer
51 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 ...
0
votes
0answers
157 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 ...
6
votes
2answers
385 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? Experimental proof of nonlocal wavefunction collapse for a single particle using ...
0
votes
1answer
87 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
votes
1answer
93 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 ...
0
votes
1answer
123 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 ...
0
votes
2answers
128 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 ...
-1
votes
1answer
76 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 ...
0
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2answers
96 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 ...
1
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0answers
41 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 ...