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Everything posted by swansont
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No, not to arbitrary precision. Not exactly sure what you mean here. Physicists have no problem approximating things, so something can be treated as being at rest despite all of the caveats we’ve mentioned.
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You don’t know what the momentum is, so saying it’s zero isn’t strictly possible, though this might be unimportant for certain problems.
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Classically, yes. It loses some meaning in QM, considering the Heisenberg Uncertainty Principle
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hijack from Help Required: Dodgy Claim by the CO2 Coalition?
swansont replied to guidoLamoto's topic in Trash Can
! Moderator Note Rule 2.12 “We expect arguments to be made in good faith. Honest discussions, backed up by evidence when necessary. Example of tactics that are not in good faith include misrepresentation, arguments based on distraction, attempts to omit or ignore information, advancing an ideology or agenda at the expense of the science being discussed, general appeals to science being flawed or dogmatic, conspiracies, and trolling.” Unsubstantiated claims and referring to science as religion are hallmarks of bad faith arguments -
Help Required: Dodgy Claim by the CO2 Coalition?
swansont replied to exchemist's topic in Climate Science
At first glance it looks like no more than the expected exponential reduction in intensity with concentration of the absorber predicted by the Beer-Lambert law. Has anyone come across this being used as a counterargument to climate change science, is the implication true that further increases should have a proportionately lesser effect and what relevance does that have to the models used to predict climate change? The radiative forcing is logarithmic in the concentration, i.e. you get a certain effect from doubling the concentration. I’m not sure of the exact number in recent literature, but it’s a few watts each time you double. So each added molecule indeed has a smaller effect. I haven’t seen this as a counterargument, but dishonesty abounds in such discussions. It’s incorporated in the models, so anyone claiming otherwise is pulling a fast one -
The wavelength is h/p, so yes, the wavelength tends to infinity as the momentum tends to zero. It can’t actually happen but can be applied as a thought experiment. There are some quantum implications to having zero momentum, and being in the rest frame is a useful approach to certain problems. The spin is not part of this; that’s a separate property. p is the linear momentum.
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“The evolution of the individual quantum states in a superposition are accurately described by an appropriate wave equation such as (eg for Dirac fermions) the Dirac equation.” I have no interest in this because my experience with superposition is with the expression of the eigenstates, and not the wave equation or how the wave function was determined. There’s no common ground for me, and so I have no comment. IOW aψ1+bψ2 doesn’t really rely on the wave equation, so I’m not sure where you were going with your post
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How does this happen? How was the superposition created in the first place? Does it even make sense to talk about the second law for such a system?
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There is no outgoing neutron
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Sure. But the superposition also includes the low-entropy state, so the average of the two (weighted by their amplitudes) is less than the entropy of the final state, so there’s no conflict with the 2nd law.
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What, precisely, is the problem?
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Yes. There’s no violation of the law when you have a superposition.
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So in what way is 1/137 “about 1”? What is your source that this is 0.998 of the experimental value?
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You did read that, but perhaps you saw that it was disputed and no example was given to support the assertion. In this example, half the energy is in each state.
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! Moderator Note Threads merged
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To add to Genady’s response: you don’t know the exact trajectory, so the photon passes through both slits and interferes with itself
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A stepper motor might be (part of) the solution..
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No, because each state has an amplitude, and the probabilities of being in the states add to 1.
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Do you have an example? Quantum states I can think of will have an energy, and you need to add energy to put a system in the ground state into a superposition of energy eigenstates (unless they’re degenerate)
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Light emiting diodes LEDs compared to laser diodes ?
swansont replied to Externet's topic in Engineering
In my experience yes. I’ve used commercially-available systems that lasted around 1.5 years or so; generally the failure was degradation of the anti-reflection coating, and the laser wouldn’t stay at the desired frequency, but they would still lase. If it’s a homemade system, it’s critical that the electronics prevent the laser from seeing voltage spikes. Those will destroy a laser diode. -
! Moderator Note The description of the sandbox: This forum is provided for members to test BB code, learn how to use the various forum functions, and generally get to grips with the system IOW it’s not for discussion. Do not expect anyone to respond.
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But you are, apparently, a word-salad smith. A neutron contains mass energy of this amount. But where is the “pure energy” that you claim it contains? How much is there? What is the evidence it exists?
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We prefer to discuss only one proposal per topic, so let's focus on your first "theory" What evidence is there of "pure energy"? Has it ever been observed? If not, how would one do so? If this energy can be converted to mass, why haven't we seen a violation of E=mc^2? One glaring problem here is that you have no mathematical framework for your idea, so that nothing can be quantified. That's a fatal shortcoming for a physics proposal.
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Fluctuating magnetic fields cause heart attacks and strokes to double!
swansont replied to LaraKnowles's topic in Physics
The length of the day is very different from what it was hundreds of millions of years ago, the length of the year isn’t constant, the orbit of the moon changes, the magnetic poles flip on occasion. Cellular functions can’t be too dependent on such external influences.