Posted: Apr 28, 2010 10:24 am
by newolder
twistor59 wrote:Newolder, is that picture actually a representation of the string landscape ? Is there any info on what the x, y and z axes are representing there ?

I simply searched google images on: string landscape : Results 1 - 21 of about 2,440,000 for string landscape. (0.13 seconds) 
I've linked that image to its blogosphere source but there's nothing there that answers your question. :(

This might help: The statistics of string/M theory vacua by Michael R. Douglas (Journal reference: JHEP0305:046,2003)
abstract wrote:We discuss systematic approaches to the classification of string/M theory vacua, and physical questions this might help us resolve. To this end, we initiate the study of ensembles of effective Lagrangians, which can be used to precisely study the predictive power of string theory, and in simple examples can lead to universality results. Using these ideas, we outline an approach to estimating the number of vacua of string/M theory which can realize the Standard Model.

Introduction wrote:... To explain our point, let us imagine the logically simplest possible discussion of “string phenomenology.” It would be to show that N different vacua of string/M theory lead to Standard Model-like physics, but with many different values of the couplings, uniformly distributed in the space of possible couplings (we will make this more precise in section 5). Now the basic number characterizing our observational knowledge of the Standard Model is the volume in coupling space consistent with observations, measured in natural units, O(1) for dimensionless couplings and O(Mnpl) for a coupling of mass dimension n. If we include as couplings the Higgs mass and the cosmological constant, this number is of order 10−120−40−10−9−9−50 ∼ 10−238, where we count as independent the probability for a model to realize the observed cosmological constant, Higgs mass, fine structure constant, electron and proton mass, and a product of all other Standard Model couplings (being generous in the assumed accuracy here). This is a very high precision, but suppose string/M theory led to 101000 vacua which matched the Standard Model gauge group and low energy spectrum. If so, it is likely that, in the absence of a selection principle, string/M theory would lead to no testable predictions at all.