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Everything posted by Bob_for_short

That's my problem  to make them inetract. I do not know how.

Temperatures at LHC collisons
Bob_for_short replied to nalxhal's topic in Modern and Theoretical Physics
Do those quarks have time to have several collisions to thermalize? If yes, then this quarkgluon plasma is as a whole at rest and it should decay in all directions equally. 
Award for discovery of bare particles
Bob_for_short posted a topic in Modern and Theoretical Physics
As you know, positrons were predicted theoretically. They were necessary part of the theory and thus were supposed to exist. Often they say that bare particles absorb infinities and this makes the theory work. Some say they are predicted by the theory. I wonder whether somebody has ever been awarded for discovery of bare particles as such? Or this important discovery was left out? 
Energy conservation in Electrodynamics
Bob_for_short replied to Bob_for_short's topic in Modern and Theoretical Physics
Yes, the incident wavetrain can get weaker if it is accompanied with the radiated wave and the resulting wave amplitude (=> energymomentum) becomes smaller. I just do not see it immediately. 
Energy conservation in Electrodynamics
Bob_for_short replied to Bob_for_short's topic in Modern and Theoretical Physics
EDIT: I can emit a halfperiod long wave from a radiotransmitter: [math]E(t)=E_0 sin(\Omega t), 0 < t < \pi/ \Omega [/math]. Then the final charge velocity will be clearly different from zero: [math]ma=F(t), v(t>\pi/ \Omega)=\int_{0}^{t}F(t')dt'=\frac{2qE_0}{m\Omega}[/math]. In addition, the charge itself radiates some new wave during acceleration period. The radiated energy is only a small fraction of [math]\frac{mv^2}{2}[/math]. What can guarantee that the total energy remains the same? 
Energy conservation in Electrodynamics
Bob_for_short replied to Bob_for_short's topic in Modern and Theoretical Physics
No, it is not Compton. Just a regular electrodynamics problem. How energy can change? Via destructive interference? How to show it? 
Let us suppose that we have a known electromagnetic wavetrain of finite size propagating in a certain direction. On its way there is a probe charge. This EMW is an external field for the charge. The EMW has a certain energymomentum (integral over the space). After action on the probe charge the wave continues its way away. In the end we have the energy of the initial wave (displaced somewhere), the kinetic energy of the charge (hopefully it starts moving), and the energy of the radiated EMF. Thus the total energy is not conserved, is it?

I submitted another note on unknown things in a well known domain; this time about the orbital momentum of particles in atoms. See http://www.science20.com/qed_reformulation_feasible/blog/unknown_physics_particle_orbital_momentum First I made a conceptual error when put R=0, but later on I gave a detailed derivation to show where the error was admitted and why this was an error (see here). Vladimir.

Explain Wave Function for a science starter
Bob_for_short replied to Dr Khan's topic in Quantum Theory
It's easy. Any meaningful picture contains many points  pixels, if you like. So one point (pixel) is not sufficient to describe the picture of a complex thing. But we may construct this picture point by point, OK? Each point belongs to the whole picture but is insufficient to represent it. Now, the wave function squared is the whole picture and each separate, elementary quantum mechanical "measurement" is a pixel of the whole picture. The wave function does not collapse while measurement. On the contrary, each "elementary" measurement is the information bit retrieval, if you like, necessary for description of a complex thing. 
I am skeptic about big bang but time is very observable thing. It cannot be separated from matter. Ask experimentalist who monitor parameters. They use clocks. Time, if you like, is a periodic process with a sufficiently short period to label different stages of the observed transient to the required by you accuracy. Using time is using at least two different in "periods" physical processes: one is "slow" (a phenomenon being observed) and the other is "quick" (used as a clock).

We do not have many wave functions but one sole (total) that represents the occupation numbers of different states (particles). Particles are just excited states of this wave function. If there is no particle, the wave function is in it ground state. On the other hand, the amplitudes of populations may be considered as "wave functions" of particular particles. It is these amplitudes that grow up and fade out in reactions. These amplitudes are responsible for probabilities of reactions. If a particular amplitude is equal to zero, it does not mean the total wave function is zero.

The prior wave functions fade out, the new one grows up. The easies way to see it is to consider the occupation numbers of different states. Occupation numbers change at a given total energy, momentum, angular momentum and maybe some other conserved quantities. Kind of balance equations.

I do not think so. For example, a decaying "particle" is first entire and after a while it decomposes into pieces. No friction is necessary to describe it.

Or deceleration of rotational motion of a twoatomic molecule ;)

See http://jayryablon.files.wordpress.com/2008/04/ohanianwhatisspin.pdf It represents spin as the energy flow of a wave packet of limited size around zaxis. However the spin does not depend on the packet size. Factually it is shown that a vector field has spin 1 and spinor field does 1/2. We knew this without wave packets.

Take a soccer ball and a rope and make a ring around the ball. Then add to the rope, say, 3 m extra and make a concentric ring around the ball. This longer ring will be at about 1 meter from the ball surface. In other words, the gap between the ball surface and the ring will be about 1 m. Now make the same procedure with the Earth. The gap will be the same  about 1 m!

Then you are unaware of the history of SR. It was a theoretical development by Lorentz, Poincaré, Einstein, Minkowski, etc., to describe the experimental data available at that moment. Read H. Poincaré who wrote articles and books, as well as gave presentations on this development and finally derived everything in his paper.

If you connect the primary and the secondary circuits, you will obtain two primary (parallel or antiparallel) circuits. Both need an external source of power supply to "operate". If there is no an external source, the current in wires will decay due to Ohm resistance, radiative losses, and the heat released in the transformer core.

Photon Polarization from Electrodynamic Potential ?
Bob_for_short replied to Widdekind's topic in Classical Physics
This is a graph of the electric force F(t) = q*E(t). Without a charge, there is no force to act on. If you speak of the field E source, it is far away, an antenna, for example. 
Photon Polarization from Electrodynamic Potential ?
Bob_for_short replied to Widdekind's topic in Classical Physics
V is written upside down and does not have a "" in the middle. 
Photon Polarization from Electrodynamic Potential ?
Bob_for_short replied to Widdekind's topic in Classical Physics
Such a field exists indeed next to a vibrating dipole (along its axis) but this variable field does not propagate too far  it decays rapidly with the distance and is called a "near field". Anyway it's an axial (radial) electric field E = grad(V). 
Fields in any understanding are some entities that carry energymomentum to be able to exchange it and be observable. Quasiparticles are described with specific quantum or classical fields. Each piece of matter has its own unique quasiparticles. In this sense their variety is enormous.

In solids there are quasiparticles with unique properties for different samples. They are studied and used in microelectronics.