Corpus ID: 235166196

Off-Diagonal Long-Range Order Implies Vanishing Charge Gap

@inproceedings{Tasaki2021OffDiagonalLO,
  title={Off-Diagonal Long-Range Order Implies Vanishing Charge Gap},
  author={H. Tasaki and Haruki Watanabe},
  year={2021}
}
For a large class of quantum many-body systems with U(1) symmetry, we prove a general inequality that relates the (off-diagonal) long-range order with the charge gap. For a system of bosons or fermions on a lattice or in continuum, the inequality implies that a ground state with off-diagonal long-range order inevitably has vanishing charge gap, and hence is characterized by nonzero charge susceptibility. For a quantum spin system, the inequality implies that a ground state within a… Expand
1 Citations
Mott Insulator-like Bose-Einstein Condensation in a Tight-Binding System of Interacting Bosons with a Flat Band
Hosho Katsura, 2, 3 Naoki Kawashima, Satoshi Morita, Akinori Tanaka, and Hal Tasaki Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, JapanExpand

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