Seminarium Fizyki Materii Skondensowanej

In systems of indistinguishable particles, the 1- and 2-body N-representability problems are of tantamount importance since their solution potentially offers an exponential computational advantage in determining the ground state (energy) over solving the N-particle Schroedinger equation. For fermions, this has already been thoroughly investigated and is know as Coulson's Challenge in Quantum Chemistry. The talk addresses the question of N-representability for systems of lattice hardcore bosons. A result on the maximal possible occupation number will be given which resembles a new 'Pauli principle' for hardcore bosons. In addition, the possibility of (fractional) Bose-Einstein condensation in a one-dimensional model system will be discussed.