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advanced_tools:group_theory:desitter [2018/03/24 11:10] jakobadmin |
advanced_tools:group_theory:desitter [2018/03/24 11:10] (current) jakobadmin [FAQ] |
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-->It ist confusing what a "five-dimensional" group like $SO(4,1)$ has to say about our four-dimensional world. Does this mean deSitter theories predict a fifth dimension?# | -->It ist confusing what a "five-dimensional" group like $SO(4,1)$ has to say about our four-dimensional world. Does this mean deSitter theories predict a fifth dimension?# | ||
- | No, recall that an explicit representation of the [[the_standard_model:poincare_group|Poincare group]] is given by $(5 \times 5)$ matrices, too! This is, because the Lorentz group transformations are $(4 \times 4)$ matrices themselves and in oredr to describe translations, we need to make these matrices into $(5 \times 5)$ matrices. See, for example, chapter 4 "The Poincaré transformations" in [[http://www.springer.com/us/book/9783642154812|Symmetries and Group Theory in Particle Physics]] by Costa and Fogly. | + | No, recall that an explicit representation of the Poincare group is given by $(5 \times 5)$ matrices, too! This is, because the Lorentz group transformations are $(4 \times 4)$ matrices themselves and in oredr to describe translations, we need to make these matrices into $(5 \times 5)$ matrices. See, for example, chapter 4 "The Poincaré transformations" in [[http://www.springer.com/us/book/9783642154812|Symmetries and Group Theory in Particle Physics]] by Costa and Fogly. |
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