arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2108.04264cond-mat.mes-hallcond-mat.othercond-mat.quant-gascond-mat.stat-mech
收藏

从Fock态出发的非平衡标量场动力学:耦合到费米子的一维声子中热化的缺失

Non-equilibrium scalar field dynamics starting from Fock states: Absence of thermalization in one dimensional phonons coupled to fermions

Md Mursalin Islam, Rajdeep Sensarma

摘要:

从非高斯初始条件出发,利用Keldysh场论,提出了一种研究标量场非平衡动力学的新方法。我们用它来研究耦合到非相互作用的玻色子和费米子浴,从初始Fock状态的声子的动力学。我们发现,在一维中,耦合到费米子浴的长波长声子在低温和高温下都不会热化。在低温下,来自能量-动量守恒的约束导致粒子-空穴激发的带宽很窄,声子有效地看不到这个浴。另一方面,强的带边发散的粒子-空穴态密度导致一个无阻尼极化激元模式以上的粒子-空穴激发的带边的修饰声子。这些无阻尼模式有助于缺乏热化的长波长声子在高温下。在更高的维度中,这些约束和态密度的发散被削弱,并导致所有波长的热化。

英文摘要:

We propose a new method to study non-equilibrium dynamics of scalar fields starting from non-Gaussian initial conditions using Keldysh field theory. We use it to study dynamics of phonons coupled to non-interacting bosonic and fermionic baths, starting from initial Fock states. We find that in one dimension long wavelength phonons coupled to fermionic baths do not thermalize both at low and high bath-temperatures. At low temperature, constraints from energy-momentum conservation lead to a narrow bandwidth of particle-hole excitations and the phonons effectively do not see this bath. On the other hand, the strong band-edge divergence of the particle-hole density of states leads to an undamped polariton-like mode of the dressed phonons above the band edge of the particle-hole excitations. These undamped modes contribute to the lack of thermalization of long wavelength phonons at high temperatures. In higher dimensions, these constraints and the divergence of density of states are weakened and lead to thermalization at all wavelengths.

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。

↑