On Wednesday, April 15, 2020 at 11:59:00 PM UTC-6, Brent wrote: > > > > On 4/15/2020 10:37 PM, Alan Grayson wrote: > > > > On Wednesday, April 15, 2020 at 10:49:45 AM UTC-6, smitra wrote: >> >> On 15-04-2020 04:20, Alan Grayson wrote: >> > On Tuesday, April 14, 2020 at 4:28:23 PM UTC-6, Bruce wrote: >> > >> >> On Wed, Apr 15, 2020 at 2:07 AM Jason Resch <[email protected]> >> >> wrote: >> >> >> >>> There has been controversy [1] in the meaning/interpretation of >> >>> the Time-Energy uncertainty relation in quantum mechanics, but >> >>> relatively none regarding the meaning of the position-momentum >> >>> uncertainty. >> >>> >> >>> However, can these not be viewed equivalently in terms of a >> >>> 4-dimensional space time? >> >>> >> >>> For example, I have seen some describe mass/energy as momentum >> >>> through time. Massless particles don't age, and have no momentum >> >>> through time. >> >>> >> >>> Similarly, cannot a point-in-time measurement be viewed as a >> >>> measurement of position in the time dimension? >> >>> >> >>> In my view, you can go from the position-momentum uncertainty to >> >>> the time-energy uncertainty simply by flipping the time-space >> >>> orientation. Is this valid? Is there something I am missing? >> >> >> >> You are missing the fact that energy is bounded below, whereas >> >> momentum can take on any value between plus and minus infinity. Time >> >> is not an operator in quantum mechanics. >> >> >> >> Bruce >> > >> > Isn't there a valid interpretation/ application of the time-energy >> > uncertainty relation in the context of emission of radiation? If so, >> > what is it? TIA, AG >> > >> The rigorous versions of these interpretations involve having some >> physical object included in the system that serves as a clock. So, if >> you actually perform a measurement involving time, then the measured >> time is represented by a physical clock. So, by including a quantum >> mechanical description of a simplified model clock, you then do get an >> observable for the measured time, despite the fact that there is no >> observable that allows you to measure the parameter t in the Schrodinger >> equation. >> >> Saibal >> > > Can you give a concrete example where the time-energy form of the UP can > be applied to? I once had an example, but can't recall what it was. TIA, AG > > > It's used all the time in interpreting collision spectra in particle > physics. A sharp resonant line in the energy spectrum implies the > generation of a long live particle, while a broad line implies a short > lifetime. > > Brent >
If time isn't an operator, why does this work? And I'm not sure how to interpret it physically. If one waits some time t, and measures in some interval t, t + delta t, do we get a spread of energies? And of what? TIA, AG -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/2986747a-b89f-4854-bfe4-c75d16ef90c0%40googlegroups.com.
