PeterDonis's latest activity
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PeterDonis reacted to PAllen's post in the thread High School Anyone come across this new YouTube channel? with
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It can become vaster per unit of stuff, everywhere. There are different metrics you can put on an infinite spacetime, and only some have... -
PeterDonis replied to the thread Graduate Does PSG require a lattice and a fundamental Hamiltonian?.Can you give a reference? This is a very specialized area of physics that you're talking about, and whatever background you can give...
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PeterDonis replied to the thread Undergrad Question about increasing laser power.The OP question has been sufficiently addressed. Thread closed. Thanks to all who participated.
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PeterDonis replied to the thread Undergrad Question about increasing laser power.You can't eliminate the laws of physics, because then we have no basis for giving any answer at all. We can't answer questions that...
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PeterDonis reacted to .Scott's post in the thread Undergrad Question about increasing laser power with Like.
You're not going to generate a laser with "infinite energy". And, if you do, those safety goggles won't do you any good. When you ask...
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PeterDonis reacted to FactChecker's post in the thread Undergrad Question about increasing laser power with Like.
You are asking if we do impossible things, can impossible things happen. Yes.
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PeterDonis replied to the thread High School Anyone come across this new YouTube channel?.This illustrates why we don't normally accept YouTube videos as valid references, and require textbooks or peer-reviewed papers.
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PeterDonis replied to the thread Undergrad Bell's theorem and measurements not done.Yes, that was Bell's point when he formulated the theorem: reality violates the Bell inequalities, so at least one of the assumptions...
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PeterDonis reacted to Nugatory's post in the thread Undergrad Bell's theorem and measurements not done with Like.
It is clearly valid to assign values to unmeasured properties of large objects and it was something of a surprise that unmeasured...
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PeterDonis reacted to Nugatory's post in the thread Undergrad Bell's theorem and measurements not done with Like.
To evaluate that we have to look at the detailed construct of the real non-idealized experiment This would be an example of the fair...
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PeterDonis reacted to Nugatory's post in the thread Undergrad Bell's theorem and measurements not done with Like.
It’s a proof by contradiction argument. The calculation is correct if the realism and locality assumptions hold; we do the experiment...
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PeterDonis replied to the thread Undergrad Question about increasing laser power.He didn't say the mirrors, he said "the ionized gas, crystal, or semiconductor" that's pumping energy into the beam. No real mirror is...
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PeterDonis reacted to .Scott's post in the thread Undergrad Question about increasing laser power with Like.
There are two kinds of lasers, continuous wave (CW) and pulse. Since you're thinking of CW, that is what I will address. Most CW...
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PeterDonis replied to the thread Undergrad Photons and free quantum particles.It isn't. It's a quantum field. Light from an ordinary lamp isn't going to exhibit any useful quantum effects; it's well described by...
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PeterDonis replied to the thread Graduate Singularity Theorems.Extremal doesn't always mean maximal. An example is a free-fall geodesic orbit around a planet; its proper time is extremal but not...