Local origin of the pseudogap in the attractive Hubbard model
Local origin of the pseudogap in the attractive Hubbard model
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DOI：
10.1103/physrevb.92.014511
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发表时间：
2015-03
影响因子：
3.7
通讯作者：
R. Peters;J. Bauer
中科院分区：
文献类型：
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作者：
R. Peters;J. Bauer
我们为三维哈伯德模型所描述的吸引费米子的赝隙物理提供了一个新的视角。在超流体跃迁的临界温度T_c以上的温度下，单粒子谱函数中的赝隙通常用预形成的未凝聚对来解释。在这里，我们证明了赝隙物理的发生可以一致地理解为局部激发，在足够大的相互作用下导致准粒子峰的分裂。当量子力学跳变是非相干时，这种效应在中高温下变得突出。我们澄清了一个推测温度的存在，低于这个温度，预计会发生赝隙物理。我们的结果是基于动力学平均场理论计算和动量独立的自能近似三维哈伯德模型的物理。我们的预测可以用目前可用的温度和光谱技术在光学晶格中的超冷原子进行测试。
We provide a new perspective on the pseudogap physics for attractive fermions as described by the three-dimensional Hubbard model. The pseudogap in the single-particle spectral function, which occurs for temperatures above the critical temperature $T_c$ of the superfluid transition, is often interpreted in terms of preformed, uncondensed pairs. Here we show that the occurrence of pseudogap physics can be consistently understood in terms of local excitations which lead to a splitting of the quasiparticle peak for sufficiently large interaction. This effect becomes prominent at intermediate and high temperatures when the quantum mechanical hopping is incoherent. We clarify the existence of a conjectured temperature below which pseudogap physics is expected to occur. Our results are based on approximating the physics of the three-dimensional Hubbard model by dynamical mean field theory calculations and a momentum independent self-energy. Our predictions can be tested with ultracold atoms in optical lattices with currently available temperatures and spectroscopic techniques.