Friday, July 21, 2006

Universe mapping

The Chapter of Not Letting the Soul of a Man Be Snatched Away from Him: I, even I, am he who cometh forth from the Celestial Water (Akeb). He (Akeb) produced abundance for me, and hath the mastery there in the form of the River.

Papyri of Ani - evansville educ


In supersymmetric theories, every fundamental particle has a superpartner. If the vacuum state happens to be supersymmetric, this would mean superpartners would have the same mass as their ordinary partners, which is clearly ruled out by experiment. Hence, the vacuum must have broken supersymmetry. Either we assume the vacuum is degenerate and SUSY is broken spontaneously, or we add soft SUSY breaking terms which break SUSY explicitly, making it an approximate symmetry. The latter approach is often preferred.

To incorporate supersymmetry into particle physics, the Standard Model must be extended to include at least twice as many particles, since none of the particles in the Standard Model can be superpartners of each other, because they have incompatible masses and quantum numbers.

With the addition of the new particles, there are many possible new interactions. The simplest possible supersymmetric model consistent with the Standard Model is the Minimal Supersymmetric Standard Model (MSSM). However, the MSSM appears to be unnatural in a number of ways, and many physicists doubt that it will be the correct theory.

A possibility in some supersymmetric models is the existence of very heavy stable particles (such as neutralinos) which would be WIMPs (weakly interacting massive particles). These would be candidates for dark matter.
For more on Supersymmetry visit wikipedia

Evaluating extreme approaches
by Lubos Motl

Pic: Origin of the Universe
from plus maths org

In the context of quantum gravity, many of us more or less secretly believe another version of the bootstrap. I think that most of the real big shots in string theory are convinced that all of string theory is exactly the same thing as all consistent backgrounds of quantum gravity. By a consistent quantum theory of gravity, we mean e.g. a unitary S-matrix with some analytical conditions implied by locality or approximate locality, with gravitons in the spectrum that reproduce low-energy semiclassical general relativity, and with black hole microstates that protect the correct high-energy behavior of the scattering that can also be derived from a semi-classical description of general relativity, especially from the black hole physics.

The worldvolumes
are spacetimes of other string theories, and so on
The paradigm of multiple quantization is also closely related to another "big idea" that is probably the most favorite of mine in this whole list. Perturbative string theory shows that the fields in spacetime are not yet fundamental: they are described by states of a more fundamental theory that lives on the two-dimensional worldsheet. Now, the two-dimensional worldsheet is described by a two-dimensional gravitational conformal field theory. Although gravity can be more or less described by a local field theory in less than four dimensions - because it has no real physics in it - you could still argue that the right way to describe a gravitational theory should be in terms of string theory. The worldsheet should be a spacetime of another string theory. And perhaps, this step could continue infinitely many times.

More on black hole final state referencing by Plato
More on Evaluating extreme approaches by Lubos Motl
Quote of the Day:
The best way to make your dreams come true is to wake up.
Paul Valery more Famous Quotes

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