[2] It was first applied to cosmology by Lee Smolin in his book The Life of the Cosmos (1997), and was first used in the context of string theory by Leonard Susskind.
If there is no structure in the space of vacua, the problem of finding one with a sufficiently small cosmological constant is NP complete.
[9] Weinberg attempted to predict the magnitude of the cosmological constant based on probabilistic arguments.
is the "anthropic selection function", determined by the number of "observers" that would occur in the universe with parameters
Technical criticisms of these proposals have pointed out that:[citation needed][year needed] Tegmark et al. have recently considered these objections and proposed a simplified anthropic scenario for axion dark matter in which they argue that the first two of these problems do not apply.
have tried is that they "predict" a cosmological constant that is too large by a factor of 10–1000 orders of magnitude (depending on one's assumptions) and hence suggest that the cosmic acceleration should be much more rapid than is observed.
[citation needed] The existence, meaning, and scientific relevance of the anthropic landscape, however, remain controversial.
[further explanation needed] Andrei Linde, Sir Martin Rees and Leonard Susskind advocate it as a solution to the cosmological constant problem.
[citation needed] The string landscape ideas can be applied to the notion of weak scale supersymmetry and the Little Hierarchy problem.
For string vacua which include the MSSM (Minimal Supersymmetric Standard Model) as the low energy effective field theory, all values of SUSY breaking fields are expected to be equally likely on the landscape.
This led Douglas[16] and others to propose that the SUSY breaking scale is distributed as a power law in the landscape
Next, one may impose the Agrawal, Barr, Donoghue, Seckel (ABDS) anthropic requirement[17] that the derived weak scale lie within a factor of a few of our measured value (lest nuclei as needed for life as we know it become unstable (the atomic principle)).
Combining these effects with a mild power-law draw to large soft SUSY breaking terms, one may calculate the Higgs boson and superparticle masses expected from the landscape.
[18] The Higgs mass probability distribution peaks around 125 GeV while sparticles (with the exception of light higgsinos) tend to lie well beyond current LHC search limits.
David Gross suggests[citation needed] that the idea is inherently unscientific, unfalsifiable or premature.
[19] The authors of two physics blogs, Lubos Motl and Peter Woit, are opposed to this use of the anthropic principle.[why?