PeterDonis's latest activity
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PeterDonis replied to the thread Graduate Topological constrains for the solutions of EFE.I don't see this claim being made in the lecture. I strongly suspect you are misinterpreting something. As I have already said in post... -
PeterDonis replied to the thread Graduate Topological constrains for the solutions of EFE.It's worth noting that this is not purely a topological restriction; the concept of a "maximally symmetric manifold" requires a metric...
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PeterDonis replied to the thread Graduate Topological constrains for the solutions of EFE.In technical language, he's talking about the possible global topology of the maximal analytic extension of a spacetime whose local...
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PeterDonis reacted to robphy's post in the thread Graduate What Exactly Is The Physical Content Of Maxwell's Equations? with
Like.
In my websearch for conventions in Geometric Algebra, I stumbled upon two vocal critics of GA (listed below). Since I am just learning... -
PeterDonis replied to the thread Graduate Topological constrains for the solutions of EFE.The topology constraint you refer to is global, not local. But the EFE is local. A global topological constraint cannot restrict the...
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PeterDonis replied to the thread Graduate What Exactly Is The Physical Content Of Maxwell's Equations?.Have you read Chapters 3 and 4 of Misner, Thorne, & Wheeler? That's where I first encountered the material that's briefly summarized in...
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PeterDonis replied to the thread Undergrad Raising and lowering indices using metric tensor.As zero, since what's inside the parentheses vanishes identically due to the symmetry of the inverse metric. Was that your point?
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PeterDonis replied to the thread Undergrad How do bar detectors work in gravitational wave detectors?.What have you read? Please give specific references.
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PeterDonis replied to the thread Undergrad 2D rotation and angular momentum uncertainty.No, when a quantum particle is confined to the ##x y## plane, its Hilbert space is restricted, and there aren't even any such operators...
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PeterDonis reacted to SiennaTheGr8's post in the thread Undergrad Raising and lowering indices using metric tensor with Like.
To be clear, the Kronecker delta is symmetric too.
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PeterDonis replied to the thread Undergrad Relativity, time, and quantum mechanics.Thread closed for moderation.
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PeterDonis replied to the thread Undergrad Relativity, time, and quantum mechanics.Which, as you've admitted, fail to achieve the purpose. So I don't understand why you are even talking about it. No, because ##\tau##...
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PeterDonis replied to the thread Undergrad Relativity, time, and quantum mechanics.Irrelevant if you are trying to analyze the bound state of an electron in a hydrogen atom. The first position measurement will ionize...
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PeterDonis replied to the thread Undergrad Relativity, time, and quantum mechanics.What pair of events? There aren't any well-defined events in the case under discussion, any more than there is a well-defined worldline...
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PeterDonis replied to the thread Graduate Feynman's bug (hot plate) in generality.That's correct. It also can't change the underlying global topological manifold--for example, it can't make a flat planar plate into a...