Condensed Matter Physics Seminar

Quantum spin models with frustrating exchange interactions are believed to support a variety of interesting ground states—e.g., valence bond crystals and spin liquids—that have no classical analogue and are best described in the language of fluctuating singlet pairs (valence bonds).But despite a rich abundance of theoretical proposals, there is still no definitive numerical approach that can be used to put these ideas on a firm footing. In this talk, I discuss elaborated resonating-valence-bond trial wavefunctions that go beyond the conventional ansatz in a number of ways. Example results are given for the square-lattice quantum Heisenberg model with frustrating next-nearest-neighbour interactions.