Quasiadiabatic continuation of quantum states: The stability of topological ground-state degeneracy and emergent gauge invariance
Quasiadiabatic continuation of quantum states: The stability of topological ground-state degeneracy and emergent gauge invariance
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DOI：
10.1103/physrevb.72.045141
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发表时间：
2005-07-01
影响因子：
3.7
通讯作者：
Wen, XG
中科院分区：
文献类型：
--
作者：
Hastings, MB;Wen, XG
我们为量子多体系统定义了量子态的准绝热延续。当哈密顿量有间隙，或者具有足够小的低能量状态密度，从而远离量子相变时，连续是有效的。这种延续将局部算子带入局部算子，同时近似保留基态期望值。我们将此延续应用于与物质耦合的规范理论问题，并提出周长定律与“零定律”的区别来识别限制。我们还将延拓应用于具有新兴规范理论的局部玻色子模型。我们证明局部规范不变性是拓扑性的，并且不能被连续或离散规范组中的玻色子模型中的任何局部扰动所破坏。我们证明，新兴离散规范理论中的基态简并性是玻色子模型的鲁棒特性，并且我们认为连续情况下局部规范不变性的鲁棒性保护了无间隙规范玻色子。
We define for quantum many-body systems a quasiadiabatic continuation of quantum states. The continuation is valid when the Hamiltonian has a gap, or else has a sufficiently small low-energy density of states, and thus is away from a quantum phase transition. This continuation takes local operators into local operators, while approximately preserving the ground-state expectation values. We apply this continuation to the problem of gauge theories coupled to matter, and propose the distinction of perimeter law versus "zero law" to identify confinement. We also apply the continuation to local bosonic models with emergent gauge theories. We show that local gauge invariance is topological and cannot be broken by any local perturbations in the bosonic models in either continuous or discrete gauge groups. We show that the ground-state degeneracy in emergent discrete gauge theories is a robust property of the bosonic model, and we argue that the robustness of local gauge invariance in the continuous case protects the gapless gauge boson.