Description |
In some fortunate cases, a field of physics is characterised by a small parameter. Perturbative methods are then available, and may lead to spectacular successes such as in Quantum Electrodynamics. In the absence of a small parameter we are at a loss of methods other than direct numerical simulation.
A less intuitive alternative is to promote the system to d dimensions and solve the large d limit, usually a feasible task, and eventually expand around. This strategy has been used with success for strongly coupled electrons, atomic physics, gauge field theory, and most recently to the dynamics of liquids constituted of spherical particles.
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