Stefan Teufel - Bohmian Mechanics
Why Physics Stack Exchange recommends it
Physics Stack Exchange answerers point people to it as a reference when explaining how Bohmian mechanics sidesteps the measurement problem and handles many-particle wave functions.
Recommended by 1 people across 1 different months, 2018 to 2024.
What it is
A 44-minute conference talk by mathematician Stefan Teufel on Bohmian mechanics, given at the 'Quantum Theory without Observers III' workshop at ZiF Bielefeld in April 2013. It presents the formulation of the theory and its mathematical structure.
What people said
Recommends Luke · 2018-08 · Physics Stack Exchange · on “Does Bohmian mechanics really solve the measurement problem?”
Bohmian mechanics cannot have a measurement problem : The word measurement does not figure in its formulation at all. It could be wrong, it could predict the wrong things, but it's actually quite correct, as one can show that for subsystems (!), Bohmian mechanics gives the same predictions as the textbook quantum mechanics . (Short comment to the other answer by akhmeteli: The "measurement problem" is not the same as "the collapse must be explained". The first one is the missing clarity and well-definedness of a theory that basically says "when we measure, something happens" without a clear equation for that. The second must be done in an approximate way since it's an effect that happens in
Cites doublefelix · 2022-12 · Physics Stack Exchange · on “Who caused first collapse of wave function?”
Your question, stated rhetorically, is itself the measurement problem. John Bell said it in a really nice way: "What exactly qualifies some physical systems to play the role of 'measurer'? Was the wavefunction of the world waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer, for some better qualified system... with a PhD?" The quote is from his 1990 article [LINK] in Physics Today . As such, there is no consensus about what the solution is, thus one could call it unsolved, though I should mention that there are solution(s) proposed. One thing that is largely agreed upon, though, is that this "cut" should no
Cites Lukas Nullmeier · 2024-09 · Physics Stack Exchange · on “Why is the wavefunction of a set of non-interacting particles a product of the individual wavefunctions of each particle in the set?”
The many particle wave function is not a product In general, the many particle wave function is not a product of single particle wave functions. In the simplest case, the $n$ -particle wave function is an element of $L^2((\mathbb R^3)^n, \mathbb C)$ . I.e., the wave function is represented by a function \begin{align} (x_1, \dots, x_n) \mapsto \Psi(x_1, \dots, x_n) \end{align} Given a number of one-particle wave functions we can construct a many particle wave function by defining $$ \Psi(x_1, \dots, x_n) := \phi_1(x_1) \cdots \phi_n(x_n)\,. $$ However, not every many particle wave function can be written in this way. Mathematically, this can also be expressed as follows. We have $$ L^2((\math