# Tagged Questions

For questions about probability, probability theory, probability distributions, expected values and related matters. Purely mathematical questions should be asked on Math.SE.

1k views

### What are the odds of finding an electron a long way from an atom? As in metres away? [on hold]

Pretty self-explanatory, heard that there is a chance that you might find an electron on the other side of the universe, just wanted to know.
26 views

1k views

### Why is a Hermitian operator a “quantum random variable”?

To me, as a stupid mathematician, a random variable is a measurable function from some probability space $(\Omega, \sigma, \mu)$ to $(\Bbb{R}, B(\Bbb{R}))$. This makes sense. You have outcomes, events,...
1k views

### Feynman random walk

In Richard Feynman's lectures on physics, chapter six, part 3, he explains something called the random walk, in which, in a succession of trials, a system moves forward one step or backward by one ...
137 views

### Is it possible to build a logical theory in QM based on quantum logic? [closed]

Quantum Probabilities as Bayesian Probability, Quantum probabilities as degrees of belief Above are two articles about quantum Bayesianism. I don't know why quantum Bayesianism use some results from ...
28 views

### Why is collision of electrons different from alpha particles in terms of probability amplitude?

In The Feynman lectures on physics volume 3, chapter 3, page 3-11, there is the following paragraph: An even more perplexing thing happens when we do the same kind of experiment by scattering ...
40 views

### Fermi-Dirac distribution - holes and electrons

The density of probability of an energy state $E$ being occupied by an electron is $$f(E,T)=\frac{1}{1+e^{\frac{E-E_F}{kT}}}$$ and the density of probability of an energy state being occupied by a ...
41 views

### Probability of measuring a pure qubit state after some unitary rotation [closed]

Suppose I have the prepared state $$|+\rangle = \frac{|0\rangle + |1\rangle}{\sqrt{2}}$$ and the unitary $Z_{\pi/2}$ which rotates a state in the Bloch sphere by $+\pi/2$ about the $z$-axis. As I ...
46 views

### probability of finding the system in the ground state [closed]

$\renewcommand{\ket}[1]{\left \lvert #1 \right \rangle}$ Assume that a quantum mechanical system is described by two orthonormal states $\ket{+}$ and $\ket{-}$, defined by the property of being ...
61 views

### Measurement of $L_z$ in a state which includes spin

I'm working through a problem on finding probabilities for measurements performed for quantities associated with one electron in three dimensions with spin. In that case we know that the state space ...
54 views

### What makes the probability distribution of a wavefunction in QM intrinsic? [closed]

I know that the usual interpretation of the wavefunction in QM is that it´s associated with a probability distribution of measurable quantities. Not a deterministic probability (like the probabilities ...
51 views