论文标题
DMRG基础状态搜索的控制债券扩展，以单一站点的成本
Controlled bond expansion for DMRG ground state search at single-site costs
论文作者
论文摘要
使用对称性的DMRG基态搜索算法必须能够通过添加或更改对称扇区来扩展虚拟键空间，如果这些扇区降低了能量。传统的单站点DMRG不允许债券扩展；两站点DMRG确实如此，但计算成本要高得多。我们提出了一种受控的债券扩展（CBE）算法，该算法以单位成本以每次扫描得出两个站点的精度和收敛性。鉴于矩阵乘积状态$ψ$定义变异空间，CBE确定了正交空间的一部分，其重量很大，并在$hψ$中显示出明显的重量，并扩大了债券，仅包括这些债券。 CBE-DMRG不使用混合参数，并且是完全变化的。使用CBE-DMRG，我们表明宽度4缸上的Kondo-Heisenberg模型具有两个不同的阶段，其费米表面体积不同。
DMRG ground state search algorithms employing symmetries must be able to expand virtual bond spaces by adding or changing symmetry sectors if these lower the energy. Traditional single-site DMRG does not allow bond expansion; two-site DMRG does, but at much higher computational costs. We present a controlled bond expansion (CBE) algorithm that yields two-site accuracy and convergence per sweep, at single-site costs. Given a matrix product state $Ψ$ defining a variational space, CBE identifies parts of the orthogonal space carrying significant weight in $HΨ$ and expands bonds to include only these. CBE-DMRG uses no mixing parameters and is fully variational. Using CBE-DMRG, we show that the Kondo-Heisenberg model on a width 4 cylinder features two distinct phases differing in their Fermi surface volumes.
