Timeline for Formalization (and meaning) of "Heisenberg Cut"
Current License: CC BY-SA 4.0
9 events
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| S Feb 9 at 1:26 | history | suggested | Kasiéobì ùdumágà | CC BY-SA 4.0 |
Very minor grammar corrections
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| Feb 8 at 23:37 | review | Suggested edits | |||
| S Feb 9 at 1:26 | |||||
| Feb 1, 2011 at 18:37 | comment | added | Roy Simpson | @Tim van Beek : As far as I know traditional AQFT is as you describe. My question, based on earlier (and now later) input from Peter, was whether QM formalisation had moved on from there. For me, Peter's reference below to POVM's alone suggests that it has. | |
| Feb 1, 2011 at 16:29 | comment | added | Peter Morgan | @Tim van Beek Agreed that a state is something mathematically rather different in AQFT than it is in classical deterministic mechanics. I suppose, however, that "the expectation value of an observable x in a state y is..." would make reasonable sense to Boltzmann or Maxwell. For AQFT, though not for QG, there's also the shared conceptual starting points of Minkowski space or curved space-time. I guess I see all this as constant evolution of concepts, not of clean breaks that disconnect us from earlier Physicists. Sorry my way of approaching your phrasing annoyed. | |
| Feb 1, 2011 at 16:15 | comment | added | Tim van Beek | @Peter Morgan: The "state" in AQFT is an appropriate state of a net of operator algebras, it is not a state in the sense of pre-QM physics. The measurement process itself is not formalized in AQFT, AQFT stops with the statement "the expectation value of an observable x in a state y is...", which is a purely quantum concept. Of course the concepts of states and measurements did exist in pre-QM physics, but AQFT is not a "quantized" classical theory like e.g. Lagrangian QFT. There is no a priori given classical theory. | |
| Feb 1, 2011 at 16:12 | comment | added | Tim van Beek | @Roy: I'd draw the line and say that everything that phycisists calculate in QM with a formalized, mathematical framework does not have any connection to any concept like the Heisenberg cut. This concept is addressed, however, by people working on the philosophical interpretation of QM like Omnes. | |
| Feb 1, 2011 at 16:02 | comment | added | Peter Morgan | I suppose "without any reference to concepts of classical physics" is a little too strong, since AQFT does have a concept of states and measurements, which did exist classically before QM, albeit without the issue of measurement incompatibilty. | |
| Feb 1, 2011 at 14:21 | comment | added | Roy Simpson | Would you say that this concept has a formalisation in some other variant of QM? After all Lubos is claiming that it can be calculated: a formula or set of axioms is what answers this question affirmatively; it is answered negatively by saying something like "QM has no such formalisation and here is the proof that none can exist..." | |
| Feb 1, 2011 at 14:05 | history | answered | Tim van Beek | CC BY-SA 2.5 |