## "Tunneling-induced restoration of classical degeneracy in quantum kagome ice"Professor Ying-Jer Kao
, National Taiwan University
[Host: Gia-Wei Chern]
ABSTRACT:
Quantum effect is expected to dictate the behavior of physical systems at low temperature. For quantum magnets with geometrical frustration, quantum fluctuation usually lifts the macroscopic classical degeneracy, and exotic quantum states emerge. However, how different types of quantum processes entangle wave functions in a constrained Hilbert space is not well understood. Here, we study the topological entanglement entropy (TEE) and the thermal entropy of a quantum ice model on a geometrically frustrated kagome lattice. We find that the system does not show a Z2 topological order down to extremely low temperature, yet continues to behave like a classical kagome ice with finite residual entropy. Our theoretical analysis indicates an intricate competition of off-diagonal and diagonal quantum processes leading to the quasi-degeneracy of states and effectively, the classical degeneracy is restored. |
Condensed Matter SeminarThursday, May 16, 2019 11:00 AM Physics Building, Room 313 Note special time. Note special room. |

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