PeterDonis's latest activity
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PeterDonis reacted to Orodruin's post in the thread I Is Zero Curvature Space Equivalent to Flat Space in General Relativity? with
Like.
”A space is flat if the Riemann curvature tensor is zero.” Of course it is, the curvature can be computed from the metric. (Assuming... -
PeterDonis replied to the thread I Question about discussions around quantum interpretations.Thread closed for moderation.
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PeterDonis reacted to Dale's post in the thread Insights The Block Universe - Refuting a Common Argument - Comments with Like.
@RUTA nowhere have I ever seen Peter Donis advocate for solipsism. Nor have I ever seen anyone else on PF do so during any block...
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PeterDonis reacted to PAllen's post in the thread Insights The Block Universe - Refuting a Common Argument - Comments with Like.
Observer dependent does not mean subjective. The latter implies it depends on state of mind (e.g. QM interpretations that attribute a...
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PeterDonis replied to the thread I Question about discussions around quantum interpretations.I don't think this is true. I believe robotic machines have been developed which can flip coins such that one side is more likely to...
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PeterDonis replied to the thread I Commutation of operators for particle in a box.In which case it's certainly not zero. So either way the OP's expectation of being able to find a common diagonalization for ##H## and...
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PeterDonis replied to the thread I Commutation of operators for particle in a box.I don't see why the potential is "troublesome"; it's a function of ##x## whose derivative won't in general be zero, so it won't commute...
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PeterDonis replied to the thread I Gravitational self-interaction: another attempt to replace Dark Matter.It is. On an initial read this paper looks like nothing more than handwaving. That's the general opinion that Deur's work was trying to...
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PeterDonis replied to the thread A Dirac's integral for the energy-momentum of the gravitational field.You're missing the point. I wasn't saying there was no reason to prefer the L-L pseudotensor to the Dirac pseudotensor; I think that's a...
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PeterDonis replied to the thread A Dirac's integral for the energy-momentum of the gravitational field.As far as I know, the same would be true if we lowered both indexes, so again, this is not a reason to prefer the form with two upper...
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PeterDonis replied to the thread A Dirac's integral for the energy-momentum of the gravitational field.You can't--at least, not if you're going to take the viewpoint of Dirac (and L-L, for that matter) that it's perfectly okay to write...
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PeterDonis replied to the thread A Dirac's integral for the energy-momentum of the gravitational field.I know you are. And you have not responded at all to my argument in post #13 for why that is not correct--why ##T_{\mu \nu}##, with two...
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PeterDonis replied to the thread A Dirac's integral for the energy-momentum of the gravitational field.Only if you think ##T^{\mu \nu}## represents what I've said it doesn't represent, and explained why. I can't remember if L-L use the...
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PeterDonis replied to the thread A Dirac's integral for the energy-momentum of the gravitational field.Well, let's see. $$ M^{\mu \nu} = g^{\mu \alpha} M_\alpha{}^\nu $$ Therefore, $$ M^{\mu \nu}_{,\nu} = \left( g^{\mu \alpha}...
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PeterDonis replied to the thread I Question about discussions around quantum interpretations.Yes, but now it's the state of atom plus environment, not just the state of the atom.