Warped Passages - Lisa Randall [251]
† Or “supergluons” in the UK.
* The neutrinos are named after the charged leptons with which they directly interact through the weak force.
* I am describing the symmetry in terms of the consequences of a transformation, but, as always, symmetry is a property of the static system. That is, the system possesses symmetry, even if I don’t actually make the transformation.
* A cookie consisting of a sandwich of two round wafers with “creme” in between.
* This runs counter to American marketing terminology, which calls small things big.
* Recall that quantum mechanics and special relativity make energies and distances interchangeable. For readability, I’ll talk in terms of energies now, but processes involving high energies are the same as processes involving short distances.
* This is a modified version of Murray Gell-Mann’s term, the “totalitarian principle,” but I think that “anarchic principle” is a closer approximation to the physics to which it’s applied.
* Remember that the uncertainty principle relates uncertainty in length to the inverse of the uncertainty in momentum.
* Howard Georgi and S.L. Glashow, “Unity of all elementary-particle forces,” Physical Review Letters, vol. 32, pp. 438–441 (1974).
* This is known as the desert hypothesis.
* Remember that virtual particles’ masses are not the same as the masses of true physical particles.
* Pierre Ramond, Julius Wess Bruno Zumino, Sergio Ferrara, and others in Europe; and, independently, Y.A. Gol’fand, E.P. Likhtman, D.V. Volkov, and V.P. Akulov in the Soviet Union.
* The universe contains dark energy (energy that is not carried by any matter), that constitutes 70 % of the total energy in the universe. Though it might explain dark matter, neither supersymmetry (nor any other theory) explains dark energy.
* Keep in mind that the quantum mechanical relations tell us that while the Planck scale length is minuscule, the Planck scale energy is enormous.
* In actuality it is a virtual photon—not a real physical photon—that is exchanged.
* In fact, compactification on a Calabi-Yau manifold preserved just the right amount of supersymmetry for the theory to reproduce features of the Standard Model. Too much supersymmetry, and you couldn’t have left-handed particles that had different interactions from right-handed ones.
* D. Gross, J. Harvey, E. Martinec, and R. Rohm, “Heterotic string theory (I): The free heterotic string,” Nuclear Physics B, vol. 256, pp. 253–84 (1985).
† Joseph Polchinski, String Theory, Vol. 1: An Introduction to the Bosonic String (Cambridge: Cambridge University Press, 1998).
* Although we can do perturbation theory when the coupling is very weak, or when there is a weakly coupled dual description of a theory with strong interactions, we have no way of using perturbation theory when the interaction strength is in the middle—that is, about 1. That means that even when there is a dual description, we don’t have a complete solution to the theory.
* Really it is a bound state of D0 branes.
* Francis Bacon, On Scientific Inquiry.
* John Ellis, Costas Kounnas, and Dmitri Nanopoulos had also considered related ideas in string theory earlier on.
* K. Square in the story. KK particles are also known as Kaluza-Klein modes, where “modes” refers to their quantized momenta.
* This is our usual counting of spacetime dimensions. Our previous discussion of Flatland in Chapter 1 preceded relativity, so we only counted spacial dimensions there.
* Remember, we have assumed no branes; this limit will change in the following chapters.
* Physicists post their papers on a website that begins with “xxx”: check out xxx.lanl.gov. Internet filters have occasionally forbidden access to this site as well.
* For brevity, I’ll refer to them collectively as “ADD.”
* Nima Arkani-Hamed, Savas Dimopoulos, Gia Dvali, “The hierarchy problem and new dimensions at a millimeter,” Physics Letters B, vol. 429, pp. 263–72 (1998).
* Remember the Planck scale length is tiny, but the Planck scale