 | Rotating Bose-Einstein Condensate Superfluids are distinguished from normal fluids by their peculiar response to rotation: circulating flow in superfluid helium, a strongly coupled Bose liquid, can appear only as quantized vortices. The newly created Bose-Einstein condensates - clouds of millions of ultracold, weakly interacting alkali-metal atoms that occupy a single quantum state - offer the possibility of investigating superfluidity in the weak-coupling regime. An outstanding question is whether Bose-Einstein condensates exhibit a mesoscopic quantum analogue of the macroscopic vortices in superfluids, and what its experimental signature would be. Here we report calculations of the low-energy states of a rotating, weakly interacting Bose gas. We find a succession of transitions between stable vortex patterns of differing symmetries that are in general qualitative agreement with observations of rotating superfluid helium, a strong-coupling superfluid. Counterintuitively, the angular momentum per particle is not quantized. Some angular momenta are forbidden, corresponding to asymmetrical unstable states that provide a physical mechanism for the entry of vorticity into the condensate. |
 | Gyro Gripping On Inner And Outer Edge Since it has mass and spin an electron is like a gyro. It can spin with its orbit or against it and if we think of the electron gripping somehow on the fabric of space then this clip can be thought to demonstrate something of what is happening there, although it is known that an electron does not spin as an object in the everyday world spins. It's spin is properly described in quantum mechanical terms and requires the special mathematics of the theory, such as is found in the Schrödinger equation for the electron. For a car wheel on the road, the bottom of the wheel is momentarily stationary, the centre moves at the speed of the car and the top of the wheel moves at twice the speed of the car. For an electron, the maximum speed of any part of its wave system is the speed of light so the electron would move at half that speed, if the analogy with a wheel holds good here. Half the speed of light is a typical speed sometimes quoted for electrons. Also, the electron radiates particles of light, photons, which seems consistent with light being involved in an electron's translation from place to place. So, although the electron has a special representation in the mathematics of quantum theory, it shows signs of being related to what is known from the everyday world of objects. See the comments for this video also. July 26th, 2008 Please read the comments by cassietcassiet for this video and my responses to them. Here is some more on Clove Theory: In the study of these matters, nobody understands anything perfectly. People work towards a better understanding, with input from others, especially through experimental results, predictive mathematics and conceptual frameworks of theories that show what is happening in physical phenomena. Clove Theory explains the universe as a packing of spheres. Regarding the question of what is the nature of orbital angular momentum and spin, the electron is a wave system and in its spin there is no overall circulation of charge. As an analogy, a cable under tension with rods inserted in it can transmit spin, though the rods don't have overall circulation; they oscillate. But an orbital can be around a molecule -- the electron does circulate there. Still, there is only one type of magnetic field, however it is produced. Clove Theory suggests that an electron is a one-clove excess over the average density of the packing of cloves. Charge is from clove density and the electron's spin is in its circulating clove density wave. Mass is from the energy stored in the deformation of cloves, by the mass-energy relation. In an orbital there is angular momentum because of the translation of the one-clove excess of the electron in addition to the spin's density wave. |
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