Particle Statistics, Frustration, and Ground-state Energy
Masaki Oshikawa
Institute for Solid State Physics, Tokyo University
Mon, Feb. 10th 2014, 14:00-15:00
Salle Claude Itzykson, Bât. 774, Orme des Merisiers
We study the connections among particle statistics, frustration and ground-state energy in quantum many-particle systems. In the absence of interaction, the ground-state energy of bosons is always lower than that of fermions because of Bose-Einstein condensation and Pauli exclusion principle. In the presence of hard-core or other interaction, however, Bose-Einstein condensation is no longer perfect and thus the comparison is not trivial. Nevertheless, the ground-state energy of hard-core bosons is proved to be lower than that of spinless fermions, if all the hopping amplitudes are non-negative. The condition can be understood as the absence of frustration among hoppings. By introducing frustration among hoppings, the ground-state energy of bosons can be made higher than that of fermions, as proved rigorously in several examples. \ \ References: \ W. Nie, H. Katsura, and M. O., Phys. Rev. Lett. 111, 100402 (2013) and arXiv:1401.2090
Contact : Gregoire MISGUICH


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