Borivoje Dakić
University of ViennaReconstruction of Quantum Particle Statistics: Bosons, Fermions, and Transtatistics

Identical quantum particles exhibit only two types of statistics: bosonic and fermionic. Theoretically, this restriction is commonly established through the symmetrization postulate or (anti)commutation constraints imposed on the algebra of creation and annihilation operators. The physical motivation for these axioms remains poorly understood, leading to various generalizations by modifying the mathematical formalism in somewhat arbitrary ways. In this talk, I will take an opposing route and show how to classify quantum particle statistics based on operationally well-motivated assumptions. Specifically, I will consider that a) the standard (complex) unitary dynamics defines the set of single-particle transformations, and b) phase transformations act locally in the space of multi-particle systems. In this way, a complete characterization, which includes bosons and fermions as basic statistics with minimal symmetry is being developed. Interestingly, we have discovered whole families of novel statistics (dubbed transtatistics) accompanied by hidden symmetries, generic degeneracy of ground states, and spontaneous symmetry breaking — effects that are (typically) absent in ordinary statistics.