Collapse Definition and 466 Threads

Hi, I am very new to this, but I can't help to ask the question to which I cannot find the answer on google. Was the process of investigating of wave collapse - split into sections - to identify which section produces the collapse? I am a web programmer and sometimes this is a method I employ...

Solving 1D Dirac equation there are 2 matrixs, and from those we get the space probability and current. If that current reflects the spin state, could happen than the EM fields from the matter acting as potentials, drives the spin to up or down, and when it reaches the north os south pole in...

I'm diving into the RQM and one thing still puzzles me. I have hard time understanding this: Taking the model system discussed above, if O′ has full information on the S+O system, it will know the Hamiltonians of both S and O, including the interaction Hamiltonian. Thus, the system will evolve...

If we consider quantum wavefunction-collapse, when we end up in a world-thread with a specific value of the measurement outcome, has information got lost?

Hi. As far as I know, during the unitary evolution of quantum states, conservation laws are respected. Obviously this can't be true for the measurement process, if we only look at the system and exclude the observer. Now the simple explanation I've heard about this is that in quantum mechanics...

Considering Bell’s theorem and the expected correlations between entangled particles or photons. In a measurement setup e.g. Like Alain Aspect‘s with 2 entangled photons. If we could make a setup that guarantees that the measurement on both photons is done at exactly the same moment, what...

Here is a presentation on the discovery of two colliding neutron stars and the resulting phenomena such as gravity waves, gamma ray bursts, and synthesis of high atomic number elements. The author is a theoretical physicist who is involved in the research. He says that the neutron stars most...

I'm trying to understand equation 209 on page 81 here: https://arxiv.org/pdf/1204.4325.pdf Here's what I understand so far: - We are to imagine a system in a superposition of |X> and |X'>, where these describe distinct particle configurations. - On the RHS of the eqn, the first term is...

Hey guys! New to the forums so unsure if this is exactly the right place to present this idea I have. I hope that you will find it interesting. I am all too familiar with claims of quantum consciousness woo. I am also aware that the role of 'wave function collapse', if such a thing even...

If MWI and collapse-theory are both possible interpretations of QM, then both of them are not a fact, right? If MWI is a fact then collapse isn't and vice versa, you could say the least. So, shut up and calculate, i.e. the minimal interpretation, makes no inference about the realness of these...

Hello: I am looking for a formula that can help me determine the collapse and deformation strengths of plastic tubing. I have been scouring the internet for this information and i have yet to find a satsifactory formula. I have found a formula that seems pretty wide spread ~ however it gives me...

I saw a paper on an experiment where a pump beam first went through a double-slit, then was downconverted with BBO. Recently a friend with a PhD in quantum physics said the downconversion will cause the pump's wavefunction to collapse and the implication for this experiment is that the pump...

Why can't absolute time be used to describe events? Previously I tried to describe entanglement collapse on this forum in terms of absolute time, but I was told more or less this was not valid. I don't understand why. If the proper time that we use is based on the fact that the speed of light...

It is often claimed in these forums and beyond that collapse in QM is completely unnecessary for one of several reasons. To be explicitly clear, collapse seen purely as a probability theoretical concept of conditional updating - i.e. treating the wavefunction as an epistemic object - isn't...

Electrons passing through a double slit is in a superposition of passing through the left slit and the right slit, thereby producing an interference pattern on the screen. But when a detector is placed to detect which slit the electrons pass through, the interference pattern is destroyed. How...

This thread is to look at the notion of wave function collapse and relativity of simultaneity. The other thread I started on QFT has helped to clarify a lot, so hopefully this one can do the same. I may have this all wrong, but I will outline my question and hopefully someone can point out...

Summary: In the past, physicists talked of the phenomenon of "wave function collapse" very freely, whereas now there seems to be some reservation about it. Why? In reading older popular physics literature, physicists used to talk about "wave function collapse" freely and more often...

A double slit experiment, is taking place. There are detectors, placed inside both of the slits. On the first run if a particle travels through one of the slits, the detector registers, that it has detected a particle, but doesn't specify which slit it has traveled through(to the conscious...

OK, so I'm trying to work out a few ideas regarding locality. I've studied at the undergrad level in the past (including quantum), but with professors that slaved away at proving math constructs and never bothered to indulge in clarifying the context of any concepts, so I'm pretty weak here...

Hello. I'd just like to check a some points concerning the two kinds of singularities that Penrose and Hawking describe in this paper. https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.1970.0021 The Singularities of Gravitational Collapse and Cosmology. 1. According to the Cosmic...

Homework Statement I have a simple cylindrical pressure vessel with thickness 100m and inner radius 254mm,.the cylnder has flat head closed ends but these are thickness 30mm. I need to calculate the pressure that would cause the vessel to collapse given material properties E=207Gpa, poissons...

One sees "Collapse" language all the time, and yet it seems there's a very simple argument that shows that it's not necessary. Suppose we measure ##\hat A## twice, at an earlier and at a later time, then the joint probability density for the measurement results being ##u## and ##v##...

Hi everyone! Sorry for the bad english! So, just a quick doubt... Does things collapse from a wave of probability into a quantum field or is the wave in the quantum field the probabilistic wave itself? An example to make it clearer: Suppose we have an atom, it enters an atom interferometer, it...

I have a basic question about magnetic fields, but the answer will help me better understand quantum collapse issues. If the current in a wire is instantaneously shut off, what happens to the magnetic field that was present when the current was flowing? To be more specific: Wire...

This is more a terminology than a conceptual question. I am proof-reading a paper (by a non-native speaker) in which the statement occurs: " the solution of the Navier–Stokes equation collapses within a finite time into simple nonlinear waves" Is this a possible phrasing? I am familiar with...

First post and I am not a scientist - just a curious soul. What stops a neutron star/magnetar from collapsing further into a black hole?

Is anyone did experiment on wave function collapse in double slit experiment. Could you please share information about that, and also share research paper about that experiment. What kind of observation done here, what kind of equipment used for that?

Why does microcausal QFT obeying the linked-cluster theorem imply there cannot be any instantaneous collapse? Is this the strongest argument against instantaneous collapse?Is linked-cluster the same concept as cluster decomposition?I found this discussion on cluster decomposition and EPR...

Is MWI equivalent to a superposition of possible Collapse-worlds? That is, is it equal to a superposition of the possible scenario's given by Collapse Interpretation? Is it imparative that the "worlds" given by MWI all ontologically exist?

The official NIST report on the collapse of building 7 on 9/11 states that the thermal expansion of a floor beam due to the fires disrupted a support column on the thirteenth floor, and that is what ultimately caused the building to collapse. Is this the sole cause or could there have been other...

Firstly i would like to say that i am not advocating the need for a conscious observer to collapse the wave function but i just want to know whether the methodology behind this experiment would prove or disprove this idea. The experiment would be similar to the quantum eraser experiment except...

I don't really know where my brain is taking me on this one. I was wondering a couple things.. You set up everything for a Slit Experiment. You shoot an atom and observed it before the slit, then somehow collected the particle. It loops back and shoots it out again, this time with the particle...

The dramatic collapse of a bridge in Italy with many fatalities has been the big item of news all over Europe. https://www.theguardian.com/world/2018/aug/15/genoa-bridge-collapse-death-toll-italy-minister-calls-resignations and many other reports. I just wonder if the qualified people here...

Because I understand that for unitary evolution, MWI is required, which suggests that for different interpretations, there may not be unitary evolution?

In his book "the black hole war" Susskind writes that in quantum mechanics information cannot be lost because it is unitary. As collapse is not unitary does he say that collapse never occurs?

When a layman like myself hears the term 'Wave function collapse' is brings to mind physical things. A wave of some sort physically getting smaller or shrinking. Obviously that's not what it is but it does sound like it. In reality, if I have it right it's just a fancy way of saying a...

Hello everyone. I am trying to solve a problem whose statement reads as follows: Neutron stars have radii of ##\sim 10## km. If we assume that before the collapse the nucleus of the white dwarf precursor has a mass equal to that of Chandrasekhar, estimate the energy generated in the collapse...

Hi everyone, I'm kind of new in the QM world and I'm having difficulties understanding the superposition and the measurement principles together with the have function collapse. This is how I understand these principles: Superposition: While not measuring, the particle is in a superpsotion of...

I would like to get your ideas on what Australian professor at ANU David Chalmers' proposes that consciousness arises out of certain configurations of complex states (Integrated information theory) and then the existence of that consciousness collapses the wave function. Specifically, why isn't...

Having in mind the idea that "information is not lost" (referring to the black hole information paradox), is not the same rule violated in the wave function collapse? I.e. during the decoherence process information is not lost as this process of entanglement of some object with its environment...

When core collapse occurs, a ~10000km diameter core of the star collapses into neutron star or a black hole. Let's look at NS case here: the resulting neutron star is on the order of 20 km across. And this happens in a few seconds. The upper layers of the star cannot immediately fall onto the...

The other day I was pondering what happens at/near absolute zero so I did some googling and found articles talking about how it has been demonstrate that as you near absolute zero, the quantum effect start to have an increased range. However, is seems that perhaps the quantum effects only get...

I want to make a comment on the Oppenheimer Snyder collapse, and before doing so want to read the original Oppenheimer Snyder paper. All I have been able to find is the paper "On continued gravitational contraction" in the Sept '39 Physical Review, but I get the impression that to most people...

Suppose you have an experiment that measures the property of an atom as a whole, maybe you can put it through a double-slit or measure its spin, whatever. Presumably that will collapse the wavefunction that you used to describe the atom in that experiment. Would this entail that in the process...

I routinely read that in quantum theory, measurement 'collapses' the wave function. I am unlikely (a geneticist, not a physicist) to understand this very well, but I think my central question is not entirely naive. Whatever the measurement 'collapse' effect really means, I don't understand...

"The pedestrian bridge in Miami that collapsed Thursday had only been put in place on Saturday under a process that allowed for installation of large sections — but that experts said left it vulnerable to collapse until it was complete." From...

Leonard Susskind said "everything that ever fell in, to make the black hole, [..] [is] all contained in [...] progressively thinner and thinner shells that approach the horizon asymptotically, never quite getting there" and from the perspective of someone outside the black hole "a shell, called...

Hi. My question is a general one but I will use an infinite well as an example. Without knowing details of the exact wavefunction I presume it can exist as a linear superposition of an infinite number of energy eigenstates ? Without knowing the exact wavefunction ; does that mean that when the...

A charged particle is passed through a beam splitter and progresses down two divergent paths. How does the charge field document this? Does the field recognize both components? Only one? And once the field is detected, defining which path was taken, does the field alter it's nature through...

I read in Griffith's quantum mechanics that in a particular system, the second time measurement of the position (say) would yield the same result (the same collapse or the same spike)given that the measurement is done quickly (since it soon spreads out). I don't understand how quick this is...