THE INTERPRETATION OF QUANTUM MECHANICS There is an uneasiness in quantum mechanics arising from the fact that all the equations and functions describe reality as being a huge mixed overlap of every possible reality, with the different realities interferring with each other according to complex number (sort of) probabilities. Reality is described by a wavefunction of every possible reality in a superposition. It is only at the very last step when a single reality is selected from this superposition, sometimes called "wavefunction collapse". People don't really know what to make of this last step but it has to be done in order to get answers that look like the reality we see, and it has been interpreted in a number of different ways. A few (heavily paraphrased) examples are as follows.

2. Consciousness causes collapse. When the wavefunction touches a mind it collapses. (Wigner)

3. Decoherence. Most of the realities fade away, just leaving a few. Interaction with the environment hastens this process. (Gell-Mann, Hartle)

4. Transactional Interpretation. Advanced waves (backwards in time waves) cause most or all of the realities to cancel out. (Cramer)

5. There are hidden variables we can never measure, and there's always only one reality. The apparent many realities arise from our ignorance of the hidden variables. (Bohm)

6. Copenhagen Interpretation. Interaction with classical (i.e. big) things causes the wavefunction to collapse. The wavefunction has no actual existence but is rather a summary of our knowledge of the system. (Bohr)

7. GRW Interpretation. Occasionally a particle undergoes collapse spontaneously and the cascade collapses the whole system. (Ghirardi, Rimini, Weber)

8. Many Worlds Interpretation. Wavefunction collapse never happens. All the realities exist even at macroscopic levels. It just looks like its collapsed because we only see a thin branch of reality. (Everett)

9. When the difference between states in a quantum system exceeds one graviton (loosely the weight of a speck of dust) the wave function collapses. (Penrose)

10. Participatory Universe. The universe evolves as a wavefunction until it starts to contain observers, and then the observers collapse the wavefunction, creating both themselves and the classical looking universe around them. (Wheeler)

Pure Momentum and Time |

In the book "The End of Time" by Julian Barbour a solution to the (currently) indefinable notion of "Now" is proposed: That it is an illusion. This solution has been offered before, but Barbour supports his argument using Quantum Physics, arguing that the universe is ultimately described by the Wheeler-DeWitt equation, the fundamental quantum physical description of the universe. Such a universe is basically an infinite collection of every possible quantum mechanical configuration of mass-energy for every possible universe. Because the configurations are described using exact position and exact energy values, quantum mechanical complementarity (the Uncertainty Principal, the more you know about some things the less you can know about others) means that such a universe is totally static and contains no time (complement of energy) and no movement (momentum, complement of position). It presents a disjoint collection of space configurations with no organizing principal to stitch them together, like individual movie frames that never connect. I quite like this view, and certainly don't dismiss it out of hand. It should be pointed out though that the Wheeler-DeWitt equation is incomplete, insoluble and possibly wrong at a fundamental level. I wonder if perhaps this not the only way to view things. If it is possible to view the universe entirely in terms of position and energy, devoid of momentum and time, then I think the spirit of quantum mechanics suggests that it is also possible to do the reverse. After all, we can choose to perform measurements of either energy OR time, position OR momentum. So the complement to the static universe of pure position and energy would be

Our universe actually (at least to me) seems to be somewhere in between the two, just as the measurements we carry out are always part position and part momentum, part energy and part time. So the universe of pure position-energy and the universe of pure momentum-time represent the extreme poles of QM, with a continuum of mixed universes in between.

333 Forum. Discus philosophy, science, logic, politics, arts, games, etc

Quake 3 Arena Stuff (Including Q3A Related Programs)

Programs (3D Models Scanner etc)

Crank Rants (Speculations on Science/Math)

John Conway's Life - The Deep Cell

Links