BB84
@BB84@mander.xyz
- Submitted 6 days ago to science_memes@mander.xyz | 4 comments
- Comment on 👁️ 🌹 💨 💨 3 weeks ago:
While it is true that space time dilation can cause red/blueshift, that is a distinct from the doppler effect which is the primary effect here.
(dilation plays only a small role: without time dilation our answer going from 700nm to 350nm would be 0.5c instead of the 0.6c calculated below)
- Comment on 👁️ 🌹 💨 💨 3 weeks ago:
One ton of TNT is 1E9 calories which is 4 gigajoules. So 0.2 petajoules should be only 50 kilotons of TNT?
- Comment on 👁️ 🌹 💨 💨 3 weeks ago:
chonk rose 😳
- Comment on 👁️ 🌹 💨 💨 3 weeks ago:
Kinetic energy or total energy? Assuming the rose weight 10 grams I get that much total energy, but only 0.225PJ is kinetic.
- Submitted 3 weeks ago to science_memes@mander.xyz | 32 comments
- Comment on Lots of 429s and broken images from mander.xyz 5 weeks ago:
Image upload fails often as well.
- Comment on vibe check 1 month ago:
Phonon Spectroscopy
- Comment on the final boss after you clear Donald Knuth 1 month ago:
As always, relevant Wikipedia links:
en.m.wikipedia.org/wiki/Al-Khwarizmi en.m.wikipedia.org/wiki/Donald_Knuth en.m.wikipedia.org/wiki/Algorithm
- Submitted 1 month ago to science_memes@mander.xyz | 87 comments
- Comment on what if the shop is empty? 1 month ago:
- Submitted 1 month ago to science_memes@mander.xyz | 16 comments
- Comment on Analysis 1 month ago:
And “choose”, of course.
- Comment on I don’t understand quantum physics 1 month ago:
You should upload this as a post!
- Comment on I don’t understand quantum physics 1 month ago:
Yeah maybe shift the X scale by 40 IQ points and it would be accurate.
- Comment on I don’t understand quantum physics 1 month ago:
Waves are underrated in pop-sci context. Even classical waves you can make with household items like strings can have counterintuitive and cool behaviors!
- Submitted 1 month ago to science_memes@mander.xyz | 28 comments
- Comment on calculate the transmission coefficient 2 months ago:
Imagine you release a ball from the top of a hill and it rolls down. The taller the hill, the faster the ball will get, the more energy it will have. If the hill is X unit high, the ball get X units of energy.
From conservation of energy, a ball with X units of energy can roll up a hill of height X before coming to a stop. If such ball is rolling on the ground and there is a hill (a “barrier”) of height greater than X in front of it, the ball will climb up X units, stop, and roll back down the same side. But if the hill is less than X tall, then the ball will roll over to the other side of the hill.
What I describe above is classical physics. It’s very intuitive and describe everyday life very well: you can try rolling balls at home too.
You can think of the wall the girl built in the meme as a kind of hill too. If you throw an electron at the wall, it gets repelled by the electrons of the atoms of the wall (in the same way the ball gets “repelled” away from the hilltop by gravity along with the slope of the hill). In classical physics, you can calculate how much energy an electron should need to surmount this repellent force and pass through the wall. This would be the height of the girl’s hill.
But it turns out that even electrons with lower energy can still sometimes pass through the wall. This is the phenomenon of Quantum Tunneling (because the particle cross through the hill without going over the hilltop: it used a tunnel). I can tell you it is a feature of the wavelike behavior of particles as quantum mechanics describe, but if you ask “why do particles have wavelike behavior” then you’ll have to see @model_tar_gz@lemmy.world ‘s answer.
The joke in the meme is that the girl thinks she is safe because she has a wall. But considering quantum effects, there can still be particles (knives) that tunnel through and hit her.
- Comment on calculate the transmission coefficient 2 months ago:
The red curve is real part of Psi 😉.
- Comment on calculate the transmission coefficient 2 months ago:
The x axis is position. The y axis is energy. The blue box is a potential energy barrier. The red curve shows the wavefunction of a particle at a certain energy level coming in and tunneling through the wall. (the wavefunction actually live on a different y-scale from this plot and is only superimposed here for illustrative purpose, so don’t read into the amplitude of the oscillatory part).
more info: en.m.wikipedia.org/wiki/Quantum_tunnelling
- Submitted 2 months ago to science_memes@mander.xyz | 11 comments