What is Bohmian mechanics: Definition and 69 Discussions
The de Broglie–Bohm theory, also known as the pilot wave theory, Bohmian mechanics, Bohm's interpretation, and the causal interpretation, is an interpretation of quantum mechanics. In addition to the wavefunction, it also postulates an actual configuration of particles exists even when unobserved. The evolution over time of the configuration of all particles is defined by a guiding equation. The evolution of the wave function over time is given by the Schrödinger equation. The theory is named after Louis de Broglie (1892–1987) and David Bohm (1917–1992).
The theory is deterministic and explicitly nonlocal: the velocity of any one particle depends on the value of the guiding equation, which depends on the configuration of the system given by its wave function; the latter depends on the boundary conditions of the system, which, in principle, may be the entire universe.
The theory results in a measurement formalism, analogous to thermodynamics for classical mechanics, that yields the standard quantum formalism generally associated with the Copenhagen interpretation. The theory's explicit non-locality resolves the "measurement problem", which is conventionally delegated to the topic of interpretations of quantum mechanics in the Copenhagen interpretation.
The Born rule in Broglie–Bohm theory is not a basic law. Rather, in this theory, the link between the probability density and the wave function has the status of a hypothesis, called the "quantum equilibrium hypothesis", which is additional to the basic principles governing the wave function.
The theory was historically developed in the 1920s by de Broglie, who, in 1927, was persuaded to abandon it in favour of the then-mainstream Copenhagen interpretation. David Bohm, dissatisfied with the prevailing orthodoxy, rediscovered de Broglie's pilot-wave theory in 1952. Bohm's suggestions were not then widely received, partly due to reasons unrelated to their content, such as Bohm's youthful communist affiliations. De Broglie–Bohm theory was widely deemed unacceptable by mainstream theorists, mostly because of its explicit non-locality. Bell's theorem (1964) was inspired by Bell's discovery of Bohm's work; he wondered whether the theory's obvious nonlocality could be eliminated. Since the 1990s, there has been renewed interest in formulating extensions to de Broglie–Bohm theory, attempting to reconcile it with special relativity and quantum field theory, besides other features such as spin or curved spatial geometries.The Stanford Encyclopedia of Philosophy article on quantum decoherence groups "approaches to quantum mechanics" into five groups, of which "pilot-wave theories" are one (the others are the Copenhagen interpretation, objective collapse theories, many-worlds interpretations and modal interpretations).
There are several equivalent mathematical formulations of the theory, and it is known by a number of names. The de Broglie wave has a macroscopic analogy termed Faraday wave.
I once conjectured that Bohmian mechanics arrived at an unfortunate point in time, when interest in QFT overshadowed potential opportunities offered by Bohmian mechanics:
One of those opportunities was the analysis of non-locality, later done by Bell, and the reason why I brought up Bohmian...
I was recently trying to understand how Bohmian Mechanics could model quantum theory. In an old lecture of Sidney Coleman's called "Quantum Theory with the Gloves off" available here:
https://www.damtp.cam.ac.uk/user/ho/Coleman.pdf
He shows with a "physicist's proof" that QM predicts truly...
I have been reading about ontologies in quantum physics recently and I came across Bohmian mechanics. If I understood it correctly BM endorses Particle ontology. Particle ontology claims that point-like particles that move continuously in time are the fundamental building blocks.
I know some...
Collapse theories (like GRW) only need extremely few collapses to reproduce macroscopic observations, and actually must limit themselves to extremely view collapses to avoid being experimentally distinguishable with current technology from standard QM. Being too generous with world splitting in...
I read in the article in Quanta magazine about an experiment with oil droplets that dooms Bohmian Mechanics, but I didn't understand why. Does anyone knows this experiment and why it dooms Bohmian Mechanics?
The article is in the link...
Hi.
In an Elitzur–Vaidman bomb tester, will the guiding wave be different in a situation with a live bomb compared to one with only a dud? And if yes, how does the bomb interact with the guiding wave? Because usually it is described as a pointlike device that only explodes when hit by the...
I recently read @Demystifier's paper entitled, Bohmian Mechanics for Instrumentalists and I found it quite interesting. There is a danger that I am guilty of a certain amount of confirmation bias, as I find that deterministic interpretations are more closely aligned to my own logical reasoning...
Regarding the paper Bohmian mechanics for instrumentalists
I like the ideas put forward in the paper because it provides a basis for an intuitive and logical explanation of quantum mechanics. I have many questions about it, but I will start with 3.
Question 1:
In this interpretation, what is...
[Moderator's note: Thread spun off from previous thread due to topic change.]
Thanks! I am working on understanding why non-local effects violate the special theory of relativity. I am not there yet, but maybe when I finally get there I will leave the BM train.
If I recall correctly it was in Adam Becker's book "What is Real?" where I read that late in life de Broglie took up again the pilot wave theory that he had introduced at Solvay in 1927 and that Bohm had done so much work on in the interim.
Did de Broglie make any contributions to pilot wave...
I have a free particle with a Gaussian wave function ##\psi(x,0) = N \exp\left(-\frac{x^2}{2}\right)##. After time evolution with ##H=\frac{p^2}{2}##, the wave function is given by ##\psi(x,t)=N\left(\frac{1}{1+i t}\right)^{3/2} \exp \left(-\frac{x^2}{2 (1+i t)}\right)##. The time evolution of a...
Title says it all. There's a new biography of David Bohm from Springer:
https://www.springer.com/gp/book/9783030227142
I thought some here might be interested in it.
Hi,
I'm reading Demystifier's article about an interpretation of quantum mechanics. One concept that seems important for this interpretation is that of what is perceptible by us human beings compared to what is not (non-perceptible).
Demystifier says: A perception by a naked eye is direct, a...
David Deutsch, a theoretical physicist, talks about David Bohm in his book "the Fabric of Reality":
"[w]orking out what Bohm’s invisible wave will do requires the same computations as working out what trillions of shadow photons will do. Some parts of the wave describe us, the observers...
Hello everyone!
Recently I saw this paper: https://arxiv.org/pdf/1304.4801.pdf ("Any nonlocal model assuming “local parts” conflicts with relativity " by Antoine Suarez).
He mentions standard experimental configuration with beam-splitters and detectors. Then he distinguishes possible models...
With respect to the following posts from a now closed thread,
https://www.physicsforums.com/threads/copenhagen-restriction-on-knowledge-or-restriction-on-ontology.968982/post-6169047...
I know that in some Bohmian papers (like https://arxiv.org/pdf/quant-ph/0303156.pdf), electron-positron pair creation and annihilation is modeled by different methods like stochastic jumps in the configuration space. My question is, is there any Bohmian approach to reproduce all of the...
In https://arxiv.org/pdf/quant-ph/0203049.pdf, which is in the realm of Bohmian mechanics, Antony Valentini claims that by having a "non-equilibrium" particle with arbitrarily accurate "known" position, we can measure another particle's position with arbitrary precision, violating Heisenberg's...
Hi all,
I've been looking at de Broglie-Bohm theory and more recent attempts at Bohm-like models that are relativistic and attempt to reproduce QFT. What I'm not clear on (non-expert) is how the vacuum is modeled in these cases? If we have a set of infinite quantum harmonic oscillators...
Look at the paper in the link below:
https://link.springer.com/content/pdf/10.1007%2Fs10701-016-0026-7.pdf
It introduces a pilot-wave model on a discrete spacetime lattice. However, the pilot-wave model is not deterministic; the motion of quantum particles is described by a |Ψ|^2-distributed...
A free electron, or any other quantum particle, has an uncertain position/momentum, according to Heisenberg uncertainty principle. The squared amplitude of the wavefunction determines the probability of finding the electron at any point of the space. Accordingly, atomic orbitals are attributed...
Does Bohmian mechanics have a mathematically well-defined initial-value problem with unique solution for given initial data?
The right hand side of the guiding equation has singularities at all configuration space positions where ##\psi## vanishes. Thus the particle dynamics breaks down.
Thus...
Hi all,
In 'Bohmian mechanics,' (BM) velocities are given by the 'guiding equation' as explained, for instance, in this article of the Stanford Encyclopedia of Philosophy https://plato.stanford.edu/entries/qm-bohm/#DefiEquaBohmMech
These velocities can, in principle, be greater than c. This...
I am looking for good references / clarifications on the subject.
First of all, my question is concerned only with mathematical formulation of something that sort of plays the role of the Feynman path integral of the "standard" QFT. It is not concerned with the physical or philosophical...
All the literature on the quantum eraser that I've seen is grounded in the Copenhagen interpretation of quantum mechanics. It's very easy to understand the experiment in those terms.
Do you know how quantum eraser experiments are interpreted by the de Broglie–Bohm theory? What is erased in this...
Bohmian mechanics requires a preferred reference frame. But String theory doesn't have any preferred frames, so isn't BM incompatible with ST?? Maybe it would be compatible with other theories of quantum gravity that permit a preferred frame (LQG, CDT)...
Bohmian mechanics claims that although it is deterministic, randomness emerges from the fact that we cannot know the initial conditions of the particle due to Heisenberg's uncertainty principle. However this experiment can put that to the test and determine whether randomness in quantum...
I always think about entanglement as pure conservation of energy and conservation of angular momentum. In fact I see that only conservation of energy is non-local, and that quantum objects have nothing to do with non-locality, for example you can entangle 2 atoms that have never interacted with...
Could you, please, give me reference to any paper or talk by Paul Dirac where he expresses his views about or give comments to the de Broglie-Bohm theory (Bohmian mechanics)?
stevendaryl, vanhees71, Demystifier, atty and others well verse in Bohmian mechanics and know the ins and outs or the basic. Some questions I'd like to ask.
1. What would happen if Bohmian Mechanic is not inherently random, for instance.. if the trajectories or initial conditions were...
I recently read this article about recent experiments which seems to be resurrecting the idea of a Bohm-deBroglie interpretation of quantum mechanics over the Copenhagen one. Is this legit, or pseudo-science hype?
https://www.wired.com/2014/06/the-new-quantum-reality/
Within the context of the de Broglie-Bohm pilot-wave theory, can anyone explain what the pilot wave is in physical terms? I’m having a hard time understanding how, for example, the pilot wave influences the trajectory of a photon in the double-slit experiment. Are we dealing with...
http://motls.blogspot.com/2014/05/measure-for-measure-debaters-love-to.html?m=1
According to lubos, bohmian mechanics is certainly wrong because "its basic classical object – the guiding wave – is in principle unobservable because a change of it should in principle impact things at a distance...
It is well known that wave particle duality was also observed with large particles up to 10000 amu:
Abstract of Paper : https://arxiv.org/abs/1310.8343
Doesn't that make pilot wave theory a more logical interpretation? For example it is easier than the whole material becoming a wave...
Are the physical properties of a particle spread out through the wave function in bohmian mechanics?
This is from wikipedia
"Also, unlike in classical mechanics, physical properties (e.g., mass, charge) are spread out over the wavefunction in de Broglie–Bohm theory, not localized at the position...
One of the favourite themes for threads which create long discussions here is on Bohmian mechanics. Unfortunately, most of them operated under the assumption that the reader is familiar with the intricacies of this ... interpretation? theory? I do not wish to rehash all that has been written on...
How does BH deal with the destruction of interference in the double slit experiment when a detector is placed at the slits? If the wave function never collapses, then shouldn't the particle still follow the path? Does the measuring device change the shape of the wave function so that it doesn't...
Reading this paper, I found their reference to a blog article by Reinhard Werner, one of the leaders in quantum information theory, on Bohmian mechanics, with sharp comments and questions such as the following:
At the end he poses http://www.itp.uni-hannover.de/~werner/Bohm.html , for which...
There is a paper by Arnold Neumaier, where it is argued that Bohmian mechanics, is simply wrong, because it doesn't predict all the results that we observe from experiment. See here.
Neumaier wrote down his argument for a particle in the ground state of a harmonic oscillator, but there's...
A yet unverified experiment may mean a paradigm shift in QM:
http://advances.sciencemag.org/content/2/2/e1501466.full
http://futurism.com/new-evidence-could-break-the-standard-view-of-quantum-mechanics/
What do you make of this?
I entered in physicsforums archive search the wildcards "bohmian why electrons don't lose energy atom" but only got one hit that isn't related to it. In Bohmian mechanics, electron is localized and has trajectory.. why can't it lose energy as it rotates around the nucleus? What wildcard words...
Equation (8) defines the conditional wave function of a microscopic physical system in terms of the wave function of the universe and the true positions of the particles in the environment (= the universe except the microscopic system). Such a definition is essential for the interpretation of...
Hi there.
I have been studying on Bell Inequalities and hidden variables problem for quite some time now however my general knowledge on the problem of superluminal communication is superficial at best. I know that non of the standing interpretations (Everett, Copenhagen, Bohmian, QBist etc.)...
Yes, the title of this thread has sounded the crackpot alarm! Anyway, I'm curious for your thoughts and suggested readings...
As background, I've learned that Neo-Lorentzian Ether Theory is a valid alternate for Einstein's Special Relativity. This ether is undetectable, but does in imply a...