Timeline for Is there a "position operator" for the "particle on a ring" quantum mechanics model?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 9, 2021 at 7:16 | comment | added | Robin Ekman | @ChiralAnomaly yes that's exactly what I'm wondering, if this is the appropriate limit/generalisation of the Newton-Wigner operator for this case. The characterisation of N-W has having localised eigenstates and a formulation in terms of detection probabilities $D(R)$ feel similar enough that this should be the case, morally speaking. | |
| May 6, 2021 at 12:44 | comment | added | Chiral Anomaly | @RobinEkman The Newton-Wigner position operator is an attempt to construct a position operator in relativistic QFT. I wrote another answer that elaborates on the situation in relativistic QFT. Here, I immediately specialized to nonrelativistic QFT (which is consistent with the question), where constructing a position operator for a single particle is not a problem. Maybe there is some sense in which the Newton-Wigner paradigm reduces to this one in the nonrelativistic limit, but I haven't checked that. | |
| May 6, 2021 at 4:06 | comment | added | Robin Ekman | This seems like it corresponds to constructing the Newton-Wigner position operator for this system. | |
| May 5, 2021 at 14:20 | comment | added | Yakk | "angular coordinate must have a discontinuity (2π jump) somewhere on the circle." Why not just use R mod 2 pi as your space? No discontinuity. I guess that doesn't fix the average problem, but the problem is no longer the discontinuity... but rather that your space doesn't have much of a notion of "average" anymore. Ok, I guess that fixes nothing. | |
| May 4, 2021 at 16:14 | vote | accept | Adrian | ||
| May 4, 2021 at 11:01 | comment | added | AccidentalTaylorExpansion | "To make things easier, here's a little QFT" I would've never thought to hear that sentence in my life. | |
| May 4, 2021 at 2:11 | history | answered | Chiral Anomaly | CC BY-SA 4.0 |