Conformal Invariance and Multifractality at Anderson Transitions in Arbitrary Dimensions.

Multifractals arise in various systems across nature whose scaling behavior is characterized by a continuous spectrum of multifractal exponents Δ_{q}. In the context of Anderson transitions, the multifractality of critical wave functions is described by operators O_{q} with scaling dimensions Δ_{q} in a field-theory description of the transitions. The operators O_{q} satisfy the so-called Abelian fusion expressed as a simple operator product expansion. Assuming conformal invariance and Abelian fusion, we use the conformal bootstrap framework to derive a constraint that implies that the multifractal spectrum Δ_{q} (and its generalized form) must be quadratic in its arguments in any dimension d≥2.