Bootstrap model

In physics, the term bootstrap model is used for the class of theories that assume that very general consistency criteria are sufficient to determine the whole theory completely. In such theories, typically examples of quantum field theory, it is impossible to divide the objects and concepts to elementary and composite ones. See Geoffrey Chew.

The bootstrap principle makes for a logically correct, but conceptually difficult, form of argument. Bootstrap models were much discussed in the 60's and 70's and formed the basis of study of the analytic S-matrix. Although the S-matrix has fallen out of favour as a way of studying strong interactions, giving way to quantum chromodynamics, there are a number of important examples of theories which use general principles to derive specific results, starting from Einstein's 1905 paper on special relativity. Similarly the form of the general theory is almost entirely specified from general principles such as the cosmological principle, to the point where only the affine connection is an arbitrary assumption. Notably that is the part of the theory which Einstein himself tried to modify in his attempts at a unified field theory.

Likewise, the quantum logic interpretation of quantum theory as a language for discussing measurement results due to Von Neumann is a matter of applying general principles of measurement. Putting this together with special relativity leads to the Dirac equation, and ultimately to qed, and bootstrap principles were at the root of the claim that the only possible model for unification is string theory, although in the view of a number of physicists that claim is wrongly founded because string theory violates a vital general principle in that it is not background independent.

Bootstrapping can also be in reference to a method by which one can reach a higher level of understanding by building off of lower levels. For example, one can bootstrap your way to a solution to any quantum mechanical problem using the infinite square well as your start. This can be proven.^{[citation needed]}