arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.02332cond-mat.str-elcond-mat.supr-conhep-th
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费米表面拓扑对费米临界性的影响:Tomonaga-Luttinger液体的实例研究

Fermionic criticality is shaped by Fermi surface topology: a case study of the Tomonaga-Luttinger liquid

Anirban Mukherjee, Siddhartha Patra, Siddhartha Lal

摘要:

我们对一维费米子哈伯德模型进行了酉重整化群(URG)研究.该方法产生了一系列的有效哈密顿量和多体本征态,这些本征态在从紫外到红外的张量网络中以全息方式排列。URG被实现为一个量子线路,从而得到了纠缠全息映射(EHM)张量网络描述。一个拓扑$Θ$ -项的投影希尔伯特空间的自由度在费米表面示出的RG流的性质,无论是无间隙的Tomonaga-Luttinger液体或有间隙的量子液相。这导致在一个非微扰版本的Berezenskiii-Kosterlitz-无干扰(BKT)RG相图,揭示了一条线的中间耦合稳定的不动点,而RG流的性质周围的临界点是相同的,从弱耦合RG分析。这与多粒子纠缠中的相变相吻合,因为纠缠熵RG流显示出取决于拓扑$Θ$项的值的临界和有间隙的阶段的不同特征。我们证明了Ryu-Takyanagi熵约束的多体本征态组成的EHM网络,具体的关系的全息对偶原则。熵束缚的尺度也区分了有隙和无隙的阶段,这意味着在临界点上产生了非常不同的全息时空。最后,我们把费米面看作是与高能电子态耦合的量子杂质。设计了一个思想实验来研究杂质分离产生的纠缠熵,并提出了通过研究量子噪声和全计数统计的高阶累积量来测量纠缠熵的方法。

英文摘要:

We perform a unitary renormalization group (URG) study of the 1D fermionic Hubbard model. The formalism generates a family of effective Hamiltonians and many-body eigenstates arranged holographically across the tensor network from UV to IR. The URG is realized as a quantum circuit, leading to the entanglement holographic mapping (EHM) tensor network description. A topological $Θ$-term of the projected Hilbert space of the degrees of freedom at the Fermi surface are shown to govern the nature of RG flow towards either the gapless Tomonaga-Luttinger liquid or gapped quantum liquid phases. This results in a nonperturbative version of the Berezenskii-Kosterlitz-Thouless (BKT) RG phase diagram, revealing a line of intermediate coupling stable fixed points, while the nature of RG flow around the critical point is identical to that obtained from the weak-coupling RG analysis. This coincides with a phase transition in the many-particle entanglement, as the entanglement entropy RG flow shows distinct features for the critical and gapped phases depending on the value of the topological $Θ$-term. We demonstrate the Ryu-Takyanagi entropy bound for the many-body eigenstates comprising the EHM network, concretizing the relation to the holographic duality principle. The scaling of the entropy bound also distinguishes the gapped and gapless phases, implying the generation of very different holographic spacetimes across the critical point. Finally, we treat the Fermi surface as a quantum impurity coupled to the high energy electronic states. A thought-experiment is devised in order to study entanglement entropy generated by isolating the impurity, and propose ways by which to measure it by studying the quantum noise and higher order cumulants of the full counting statistics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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