Recent content by greypilgrim

https://onlinelibrary.wiley.com/doi/abs/10.1002/piuz.201501412 But it's behind a paywall. But isn't ##A_1 B_1+A_1 B_2+A_2 B_1-A_2 B_2=A_1 (B_1+B_2)+A_2 (B_1-B_2)=\pm 2## assuming a single experiment?

It's "Physik unserer Zeit", 6/2015 (46), "Endspiel für den lokalen Realismus".

I can, but it's in German.

Thanks! The article I was reading proved that ##\langle A_1 B_1 \rangle+\langle A_1 B_2 \rangle+\langle A_2 B_1 \rangle-\langle A_2 B_2 \rangle\le 2## by using ##A_1 B_1+A_1 B_2+A_2 B_1-A_2 B_2=A_1 (B_1+B_2)+A_2 (B_1-B_2)=\pm 2## which only makes sense if all four values are defined, even if...

Hi. I can calculate the expectation values in the Bell (or in this case, CHSH) inequality and show that they violate it for entangled particles. But I'm confused about how to calculate them for an actual sequence of measurements, which could look like this ("Paar" is for photon pair): How do...

I don't quite understand that part. Assuming we work in SI units and have a value for ##c## obtained by direct measurement, now we build a field theory consistent with SR. So you're saying from this one measurement value ##c## we then can derive BOTH ##\varepsilon_0## AND ##\mu_0##? The...

Hi. The numerical value of the speed of light ##c## pops out as propagation speed of the wave solutions to Maxwell's equations. It seems like everywhere else we need to plug in ##c## as a parameter. Why is that? Is there a way to "derive" the numerical value of ##c## in other theories, that...

Hi. I've seen single slit diffraction being brought up as an example of the uncertainty principle: Narrowing the slit restricts the particles more in one dimension, which means the momentum in this dimension is more uncertain, which results in a more spread-out diffraction pattern. I've even...

Hi. If I drop an inelastic body, its potential energy first gets converted to kinetic, then to deformation energy. We use conservation of energy without taking into account the kinetic energy gain of the earth during the fall. However, at first sight conservation of momentum seems to be...

Hi. A plate capacitor is connected to a constant voltage source. The stored energy is $$W=\frac{1}{2}\cdot C\cdot U^2=\frac{1}{2}\cdot \varepsilon_0\frac{A}{d}\cdot U^2\propto\frac{1}{d}$$ if the voltage source remains connected when varying ##d##. So the energy decreases with increasing...

Hi. I was surprised when I first read that there's quite a couple of unsolved problems in classical electrodynamics, such as the Abraham–Lorentz force. I have a couple of questions about that: Do those difficulties only appear for exact point-like particles? Do they all vanish with continuous...

But if I use rice that has been in contact with room air for a while, wouldn't it already have absorbed enough water to be in equilibrium with the vapor pressure of the air? Why would it still lower the humidity of the air around the phone? Why is the humidity of the air next to the phone...

Does that mean I'd need rice from a sealed package? I reckon any rice that had been stored in contact with the ambient air would already have absorbed enough water to be in equilibrium with that vapor pressure again.

Well the rice isn't touching the water inside the phone, is it? And I'd surely dry off the water on the outside first before placing it in the rice.

Hi. The usual recommendation for a phone that got wet is not trying to turn it on again and place it in rice overnight as the rice will absorb humidity. But is there any advantage over leaving it in a big, maybe ventilated room (and maybe placing it upright)? If a water molecule leaving the...