From the pseudogap metal to the Fermi liquid using ancilla qubits
From the pseudogap metal to the Fermi liquid using ancilla qubits
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DOI：
10.1103/physrevresearch.2.023172
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发表时间：
2020-01
期刊：
影响因子：
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通讯作者：
Ya-Hui Zhang;S. Sachdev
中科院分区：
文献类型：
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作者：
Ya-Hui Zhang;S. Sachdev
我们提出了空穴掺杂铜酸盐的一个新的部分子理论，描述了从小费米面的赝隙金属到大费米面的传统费米液体的演化。我们引入了每平方格点2个Ancilla量子比特，并利用它们得到了分数化费米液体对赝隙金属态的变分波函数。我们提出了铜酸盐的多层哈密顿子，电子驻留在“物理”层，Ancilla量子比特驻留在两个“隐藏”层：通过正则变换可以将隐藏层与物理层解耦，从而使隐藏层处于微不足道的有缝态。这个哈密顿量产生了一个浮现规范理论，它不仅描述了分馏的费米液体，而且还描述了传统的费米液体，以及可能的奇异中间相和临界点。分馏的费米液体有空穴，其准粒子重量只在“费米弧线”上大，费米自旋激发携带浮现规范场的电荷。
We propose a new parton theory of the hole-doped cuprates, describing the evolution from the pseudogap metal with small Fermi surfaces to the conventional Fermi liquid with a large Fermi surface. We introduce 2 ancilla qubits per square lattice site, and employ them to obtain a variational wavefunction of a fractionalized Fermi liquid for the pseudogap metal state. We propose a multi-layer Hamiltonion for the cuprates, with the electrons residing in the 'physical' layer, and the ancilla qubits in two 'hidden' layers: the hidden layers can be decoupled from the physical layer by a canonical transformation which leaves the hidden layers in a trivial gapped state. This Hamiltonian yields an emergent gauge theory which describes not only the fractionalized Fermi liquid, but also the conventional Fermi liquid, and possible exotic intermediate phases and critical points. The fractionalized Fermi liquid has hole pockets with quasiparticle weight which is large only on "Fermi arcs", and fermionic spinon excitations which carry charges of the emergent gauge fields.