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Jul
15
comment How can molecule of a few angstroms absorb visible light of a few hundred nanometers?
About shortening classical antennas - typically, ceramic "chip" antennas can be used to reduce the quarter-wave antenna size due to their much higher dielectric constant. You can pack a copper antenna into a size one tenth of the quarter-wave (in vacuum). There are obviously other drawbacks with these though.
Jul
12
answered Collision Resolution System Adding Velocity Into System
Jul
3
reviewed Approve suggested edit on Why do the planets' orbital distances fall on an exponential curve?
Jul
2
comment How does buoyancy work?
Right, I was reading your question which basically makes sense, but in your first comment I lost track of what it is you have a problem with in the first place :) By the way, this visualization is nice (click to enable Buoyancy visualization): phet.colorado.edu/sims/density-and-buoyancy/buoyancy_en.html
Apr
5
awarded  Yearling
Mar
29
awarded  Popular Question
Mar
25
comment Simultaneous Charging and Discharging Capacitor
i think a drawing of what you're actually asking is the way to go for stuff like this. but, it sounds like at least you're misunderstanding how a capacitor works. there are no separate charge or discharge "ports", you can think of the capacitor just like a re-chargeable battery in this context. you hook it up to a power line and it will absorb energy if the power voltage is high and release energy if the power voltage is low. very simplified... so, the process you describe is the standard process for all "storage buffers" (or UPS, uninterruptible power supplies).
Feb
26
answered Can a simulated Universe simulate Special Relativity
Feb
17
comment Why doesn't everything expand when the universe expands?
yes, seems like exactly the same question...
Feb
13
comment What low-level process drives a frequency-doubling crystal?
Thanks, and +1 for the link to the non-linear optics lectures as well. When you write that the crystal is pumped by a strong laser field, would you say that the doubling process can't happen without a macroscopic amount of photons in the process? Or it's more like you use the strong laser field to get a usable signal in practice?
Feb
12
revised What low-level process drives a frequency-doubling crystal?
added a supplement to the primary question
Feb
12
comment What low-level process drives a frequency-doubling crystal?
Thanks, yeah I have a bunch of other processes I'd like to understand at this level once we're done with this one ;) What's also interesting is what the "entropic getaway" is for this situation - I assume there are strict demands on the incoming photon kinematic properties (since in general you can't make nice high-energy photons out of chaotic heat photons).
Feb
11
asked What low-level process drives a frequency-doubling crystal?
Feb
9
awarded  Custodian
Feb
9
reviewed Approve suggested edit on What are the correct initial conditions for the moon (in a simulation)?
Feb
6
comment What is the point of path integral for boson and fermion?
are you really asking about the difference between quantum mechanics and QFT? and what book?
Jan
21
comment Why do electromagnetic waves oscillate?
Right - well for that you don't actually need to invoke any very low-level descriptions, you just need to consider the concept of energy and the de Broglie relation between energy and frequency. An emitted physical photon oscillates at a certain frequency (has an energy) related to the loss of energy at the source. A simplified description would say that a certain bound electron in an atom itself oscillates at frequency f1, falls to f2, and emits a photon of f=f1-f2, as an example. The frequency of oscillation in essence is the definition of energy.
Jan
17
comment Why are two independent sources incoherent?
Maybe the more leading question is the reverse: why would independent sources be coherent (or correlated)?
Jan
17
answered Why do electromagnetic waves oscillate?
Dec
4
answered How does interference move energy from destructive to constructive regions?