Timeline for Expectation values of $x$, $y$, $z$ in hydrogen?
Current License: CC BY-SA 3.0
11 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 21, 2016 at 22:47 | history | edited | Qmechanic♦ | CC BY-SA 3.0 |
deleted 1 character in body; edited tags; edited title
|
| Oct 21, 2016 at 7:18 | comment | added | knzhou | Again, it is possible for $\langle x \rangle$ to be zero and for $\langle f(x) \rangle$ to be nonzero. | |
| Oct 21, 2016 at 7:17 | comment | added | Prasad Mani | But it is a good bet that for a large number of measurements of the spatial co-ordinates (expectation values), i would get $0$ which contradicts(?) $\langle r \rangle$ | |
| Oct 21, 2016 at 7:15 | comment | added | knzhou | If you make a measurement, you've completely changed the state! And just because $\langle x \rangle = 0$ does not mean you'll always measure zero... Also, you measure $x$, not $\langle x \rangle$. A lot of this sounds very confused. | |
| Oct 21, 2016 at 7:14 | comment | added | Prasad Mani | But it does tell me that if i happen to measure $\langle x \rangle$ , $\langle y \rangle$ and $\langle z \rangle$ simultaneously, i get $0$ for all three meaning the spatial co-ordinates ($x,y,z$) is on an average $0$ but the average of the magnitude of the distance of electron from the nucleus $\langle r \rangle$ is not ? | |
| Oct 21, 2016 at 7:12 | comment | added | knzhou | The point is that $\langle x \rangle = 0$ really doesn't tell you anything about whether $\langle f(x) \rangle = 0$. It's not a coincidence, it follows from symmetry, but it has little to do with $\langle r \rangle$. | |
| Oct 21, 2016 at 7:10 | comment | added | Prasad Mani | Yes, i know that the value of $\langle x^2 \rangle$ is non zero; my question is that whether the $\langle x \rangle$ is just mathematical and should be treated as coincidental/irrelevant to the $\langle r\rangle$ ? | |
| Oct 21, 2016 at 7:08 | comment | added | knzhou | It is possible for $\langle x \rangle$ to be zero but $\langle x^2 \rangle$ to be nonzero. For example, consider $x = \pm 1$ with equal probability. | |
| Oct 21, 2016 at 7:04 | answer | added | John Rennie | timeline score: 3 | |
| Oct 21, 2016 at 7:03 | comment | added | Prasad Mani | I could see how my question is related to the answer to this question, but i want to understand what it means physically | |
| Oct 21, 2016 at 6:51 | history | asked | Prasad Mani | CC BY-SA 3.0 |