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bio website motls.blogspot.com
location Czech Republic
age 40
visits member for 3 years, 8 months
seen 1 hour ago

Hi, I am a string theorist and a publicist.


Sep
5
comment What is R-symmetry with supersymmetric theory?
I noticed that you added a link - and you are aware - of the Wikipedia entry on that. What's wrong with that? I am unhappy to hear it was not useful because I started that Wikipedia page, too. ;-)
Sep
5
answered What is R-symmetry with supersymmetric theory?
Sep
5
revised Lie algebra - basis for adjoint matrix products in SU(N)?
added 194 characters in body
Sep
5
answered Lie algebra - basis for adjoint matrix products in SU(N)?
Sep
4
comment Derivation of formula of potential energy by a conservative force
Because if the kinetic energy increases, then the velocity - an increasing function of energy - increases as well (the velocity was positive, by assumption), and increasing velocity (acceleration to the right side) is achieved by a positive force, too.
Sep
4
comment Why does a wave actually diffract?
Well, waves are somewhat like diffusion, partly very different. They're different equations. Both have the Laplacian for spatial coordinates but the wave equation has the second derivative in time, while the diffusion has the first derivative in time. So the diffusion diffuses while the wave equation tends to preserve the wavelength.
Sep
4
awarded  electrons
Sep
3
comment Electron Charge is 150%?
But it is true that many of these empirical observations may be deduced by purely theoretical arguments, at least when we assume some of the empirical observations. Also, many worlds with wrong values of charges etc. wouldn't admit life so even without direct observations, one could prove many of the statements by the pure "anthropic" reasoning.
Sep
3
comment Electron Charge is 150%?
Well, indeed, helium's nucleus has charge $+2e$ and it attracts double electrons. But because the minimum atom with 1 electron exists, the minimum nucleus - the proton - has $+e$. There exist high-brow proofs that the electric charge ratios can't be irrational - linking things like magnetic monopoles and quantum gravity - but I am afraid that you don't have the background for those. Sometimes we just use the observations - nuclei with $e/2$ don't exist - for example.
Sep
3
revised Quartic terms as two particle interaction?
added 22 characters in body
Sep
3
comment Relative velocity of two cars
"And each time I try, I go with a different approach" - That's an interesting observation. Have you tried to calm down and observe yourself why your reasoning is so chaotic? Some other people learn the art of self-control so every time they try, they may repeatedly use the same correct approach that they previously identified to be correct.
Sep
3
answered Why group velocity represents energy or information transmission? What relation between phase velocity and special relativity
Sep
3
comment Why group velocity represents energy or information transmission? What relation between phase velocity and special relativity
Chris, but only if the whole wave is unphysical. If there are waves of a real physical medium or field that have been properly localized or assigned to the points, the group velocity is the same thing as the speed of the packets and be sure that the packets do spread information.
Sep
3
answered Independent components in a 4-vector representing massless fields
Sep
3
comment Why does a wave actually diffract?
Thanks for your interest. I might but I would probably fail to explain it if we couldn't rely on intrinsically mathematical thinking, anyway. Maybe I should have used a simpler, non-mathematical example, like spreading of fire. Imagine that the wavefront is like the beginning of fire that spreads. Fire will also spread in circles and around the corner, right?
Sep
3
comment Really Struggling in electronics. What to do?
Maybe I should have linked to en.wikipedia.org/wiki/Bipolar_junction_transistor - See also this 20-minute video youtube.com/watch?v=3YAmmUE-0jA - Or this 5-minute video youtube.com/watch?v=9CrcRabTQ0s
Sep
3
comment Really Struggling in electronics. What to do?
Why don't you find the concepts e.g. on Wikipedia? Like on pages such as en.wikipedia.org/wiki/Transistor
Sep
3
answered Why does a wave actually diffract?
Sep
3
comment Gravity in spacetime
Incidentally, the correct claim about "straightening of trajectories" is one that one may derive from the relativistic theory of gravity, general relativity, but the dynamics isn't trying to make the trajectories "parallel to other objects' trajectories". Instead, general relativity implies that the trajectories of freely falling bodies are straightest possible (geodesics) according to the local (generally curved) geometry of the spacetime.
Sep
3
comment Gravity in spacetime
But you have been given the answers several times in about 10+ comments here (starting with Danu's "No") so why do you keep on repeating the stuff that you want others to "confirm" your claims? Has there been any ambiguity about the conclusion that your proposition is incorrect? How many kilobytes of texts do you need to understand "No"?