Simply speaking, charge conjugation is a symmetry between particles and antiparticles, and so CP-symmetry was proposed in 1957 by Lev Landau as the true symmetry between matter and antimatter. In other words, a process in which all particles are exchanged with their antiparticles was assumed to be equivalent to the mirror image of the original process.
There's three ways to make antimatter. Flip it like a mirror. Switch the charges. Reverse time.
That page is about how CP-symmetry isn't actually true though. The real symmetry is CPT, which implies that to get antimatter you need to take the mirror image and reverse time.
Also, is rotating something in a 4d universe really the same as taking the mirror image in 3d? Shouldn't you also have to invert the fourth axis?
CPT symmetry gives you the entire correct physics back. CP gets you antimatter, but not the same physics. Because there are some processes in physics that can tell whether or not time is reversed, and if you reverse them they come out differently. But as long as we're talking matter to antimatter, CP is enough.
Here's why you need CPT symmetry to recreate normal physics.
The DownBottom meson oscillates between B-Dbar decaying into Bbar-D and vice versa.
The decay rate for the two transitions are different. Transforming from Bbar-D happens at a lower rate than turning back.
This means that when you play time forwards, the particle spends most of its time with a Down quark made of matter, and when you play time backward, it spends most of its time with the Down-bar quark made of antimatter. The particle has a preference for Down matching its arrow of time to the one we expect for matter, rather than antimatter, REGARDLESS OF which way time is running.
That means you can't reverse a reaction involving the DownBottom meson. Your reaction is most likely to launch it with the D in +T, but in -T you're most likely to get a Dbar back instead, which ruins your reaction's reversibility. To make THIS reaction behave normally, you can't just flip T. You also have to flip C and P.
Yes. This and that the world still exists is good evidence that this idea doesn't actually create antimatter. There's a few reasons it might not.
A) Magic. It's smart enough to not let you make antimatter. You get back normal matter.
B) Physics. We're wrong about it. Obviously, since OUR model of physics says things like incubators and magic don't exist, and entropy can't be reversed, and there isn't a fourth spatial dimension to rotate things into to make hammerspace with. So trying to apply real world physics to this one is an insta-disproof. The problem is we have to make a new theory that looks enough like our world that we can still have things like little girls and cakes in it.
C)
ACHEM. So assuming it behaves NORMALLY. As it rotates out of our dimension into the fourth, there's less of it IN our dimension. If that "less of it" means it interacts more and more weakly with our physics, then if it tries to come back in flipped, we have a grace period. If you try to bring your teacup back flipped as antimatter, it will experience an explosive knockback that abrades its leading edge where it begins to interact more and more with normal matter. This will make it topple and fall over the OTHER way, so matter objects only ever get pulled out of hammerspace facing the correct way and not being flipped into antimatter - because trying to pull it out flipped requires you to pull harder than the E=MC2 trying to blow it up back into hammerspace. And you ain't doing that.
That page is about how CP-symmetry isn't actually true though. The real symmetry is CPT, which implies that to get antimatter you need to take the mirror image and reverse time.
Also, is rotating something in a 4d universe really the same as taking the mirror image in 3d? Shouldn't you also have to invert the fourth axis?
Physics in PMAS are fundamentally different at a very deep level, there's a coherent explanation for this that involves a completely new set of laws that don't reveal themselves until we reach the quantum level, and we're witnessing the first grand work of the next Greg Egan.
Firn is handwaving some things with magic.
So which do we think is more likely? If the second, I'd expect our fourth dimension to be essentially "conceptual", no interaction with real physics and it's only accessible by magic. Rotating things using the fourth dimension does what you'd "expect". If the first, I think that I'm going to have to spend some time reading up on topology, compact dimensions, and the history of modern physics, so that I can formulate some appropriate hypotheses and come up with tests for them.
Paper isn't 2D, neither is the graphite you rubbed on it. If Cube reaches down into Flatland and grabs a d, and puts it back as a b, he made antimatter. And if Hypercube reaches down into Spaceland and grabs a teacup, and puts it back down as a mirror teacup, that teacup's made of antimatter now.
I think it has something to do with how each particle is rotated along the 4d axis. I don't know; I only have passing familiarity with multidimensional mechanics.
Jokes aside, given that Mami's been doing this for ages and Mitakihara's curriculum probably covered this, given how absurd it is, asking Mami about it probably really is the simplest way to resolve this.
Paper isn't 2D, neither is the graphite you rubbed on it. If Cube reach down into Flatland and grabs a d, and put it back as a b, I made antimatter. And if Hypercube reaches down into Spaceland and grabs a teacup, and puts it back down as a mirror teacup, that teacup's made of antimatter now.
Jokes aside, given that Mami's been doing this for ages and Mitakihara's curriculum probably covered this, given how absurd it is, asking Mami about it probably really is the simplest way to resolve this.
On the other hand, maybe she's aware of it and just carefully keeps the teacup unrotated. Hey, maybe that's how her nuclear bomb level Tiro in Rebellion works!
Because then they wouldn't rotate out of existence, they'd rotate into thin and exceedingly brittle plates that looked like a cross section of what they were. This has already been disconfirmed by Mami's teacup.
Because then they wouldn't rotate out of existence, they'd rotate into thin plates that looked like a cross section of what they were. This has already been disconfirmed by Mami's teacup.
Because then they wouldn't rotate out of existence, they'd rotate into thin and exceedingly brittle plates that looked like a cross section of what they were. This has already been disconfirmed by Mami's teacup.
If they were just rotating you'd still end up with a zero width cross-section. I'm not quite sure what that looks like in practice, but I don't think you'd get something that doesn't seem to interact with reality at all until reversed the way Mami's teacup trick works.
It's a fourth, flat (well, as flat as space-time gets) spatial dimension. It's a 100m hypersphere, yes. There was no noticeable atmospheric pressure, no, and moving it felt normal.
4. We'll get a sharp pain in our skulls if we try rotating anything in 4D. The incubators had to build in a safeguard after a (thankfully small) prehistoric anti-matter explosion they have since removed the evidence for.
A hypersphere doesn't have north and south poles for an axis like a regular sphere does. It has a center, like a circle does, and two equators, in the same way a circle has a circumference. It rotates in two mutually perpendicular ways at the same time, without either plane of rotation crossing or interfering with the other. What this means is we can store an arbitrary amount of kinetic energy in an off-plane rotation, by making a grief flywheel and spinning it up anabove us and parallel to us. The OTHER plane of rotation allows us to dip it down into reality wherever we like, and back up whenever we're done, without interfering with the flywheel rotation. We attach our hammer to it. Kinetic impactor, 100m range. Perfect stealth. Arbitrary force.
Ladies and gentlemen. I give you... THE BANHAMMER.
A hypersphere doesn't have north and south poles for an axis like a regular sphere does. It has a center, like a circle does, and two equators, in the same way a circle has a circumference. It rotates in two mutually perpendicular ways at the same time, without either plane of rotation crossing or interfering with the other. What this means is we can store an arbitrary amount of kinetic energy in an off-plane rotation, by making a grief flywheel and spinning it up anabove us and parallel to us. The OTHER plane of rotation allows us to dip it down into reality wherever we like, and back up whenever we're done, without interfering with the flywheel rotation. We attach our hammer to it. Kinetic impactor, 100m range. Perfect stealth. Arbitrary force.
Ladies and gentlemen. I give you... THE BANHAMMER.
