PeterDonis's latest activity
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PeterDonis replied to the thread I Question about discussions around quantum interpretations.I think you have it somewhat backwards. In a typical quantum experiment, we prepare a system, it goes through some kind of process, and... -
PeterDonis reacted to Orodruin's post in the thread I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime? with
Like.
I believe that is intrinsically applying the Levi-Civita connection as the geodesics of the Levi-Civita connection are the paths that... -
PeterDonis reacted to Nugatory's post in the thread I Synchronizing clocks in an inertial frame if light is anisotropic with Like.
Does that force us to deal with clock synchronization? Start with a source of light signals and a mirror, move the mirror around until...
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PeterDonis reacted to Nugatory's post in the thread I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime? with Like.
When @geordief wrote that he was still under the misunderstanding that “I think parallel transport relies on these tangent planes [that...
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PeterDonis replied to the thread I Gauss' law seems to imply instantaneous electric field propagation.Moderator's note: Posts from the second thread the OP started on the same topic have been moved to this thread. @Bob44 there is no need...
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PeterDonis replied to the thread I Synchronizing clocks in an inertial frame if light is anisotropic.I don't think distance itself is something in people's heads. But definitions of units of distance are. As you note, the SI definition...
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PeterDonis reacted to PAllen's post in the thread I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime? with Like.
Note, there are other ways to define intrinsic curvature constants. For example, consider the area of a small circle on the surface of a...
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PeterDonis replied to the thread I Schrödinger equation and classical wave equation."I've heard" is not a valid reference. If you can give us references to actual textbooks or peer-reviewed papers that make statements...
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PeterDonis replied to the thread I Schrödinger equation and classical wave equation.Again, there's a lot in your post #1, and I'm not sure which question you're talking about. I only confirmed that ##\Psi## is a...
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PeterDonis reacted to Nugatory's post in the thread I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime? with Like.
They aren't "on" the sphere anywhere. There is a mapping from each point on the surface of the sphere to a two-dimensional vector space...
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PeterDonis replied to the thread I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?.The mathematical sphere is a model. It's not anything in reality. We often use models to make predictions about reality, but that...
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PeterDonis replied to the thread I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?.They are mathematical abstractions that rely on the fact that, locally, the sphere looks flat (the effects of its curvature get smaller...
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PeterDonis replied to the thread I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?.No, they aren't. Tangent spaces do not rely on any embedding. People often visualize tangent spaces using such an embedding, but that's...
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PeterDonis reacted to pervect's post in the thread I Synchronizing clocks in an inertial frame if light is anisotropic with Like.
I'd like to expand on my earlier point. Suppose we have some frame in which Newton's laws work. Two equal masses moving in opposite...
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PeterDonis replied to the thread I Question about discussions around quantum interpretations.Robert Leighton was a physicist and coauthor of the Feynman lectures. His son Ralph Leighton was not, nor did he ever claim to be...