Controllable finite-momenta dynamical quasicondensation in the periodically driven one-dimensional Fermi-Hubbard model
Controllable finite-momenta dynamical quasicondensation in the periodically driven one-dimensional Fermi-Hubbard model
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DOI：
10.1103/physreva.101.033604
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发表时间：
2019-06
影响因子：
2.9
通讯作者：
M. W. Cook;S. Clark
中科院分区：
文献类型：
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作者：
M. W. Cook;S. Clark
在Hubbard模型的强相互作用极限下，局域双占位形式的有效硬核玻色子激发，称为doublons，由于能量守恒，它是长寿命的。利用含时密度矩阵重整化群，我们数值研究了一维空间中由空间受限带绝缘态突然膨胀引起的双光子动力学。通过分析多体状态内的自然轨道的占领标度，我们表明，doublons动态quascondensate在带边缘，与自发出现的eta-quascondensate一致。在此基础上，我们研究了在膨胀过程中周期性驱动系统的效果。Floquet分析表明，双跳和双排斥被驱动强烈重整化，打破了哈伯德模型的eta-SU（2）对称性。对驱动膨胀动力学的数值模拟表明，驱动振幅可以控制双光子准凝聚态的动量。这些结果指出了工程非平衡凝聚体在费米冷原子实验的新途径，并可能相关的驱动固态系统。
In the strongly interacting limit of the Hubbard model localized double-occupancies form effective hard-core bosonic excitations, called a doublons, which are long-lived due to energy conservation. Using time-dependent density-matrix renormalisation group we investigate numerically the dynamics of doublons arising from the sudden expansion of a spatially confined band-insulating state in one spatial dimension. By analysing the occupation scaling of the natural orbitals within the many-body state, we show that doublons dynamically quasicondense at the band edges, consistent with the spontaneous emergence of an eta-quasicondensate. Building on this, we study the effect of periodically driving the system during the expansion. Floquet analysis reveals that doublon-hopping and doublon-repulsion are strongly renormalised by the drive, breaking the eta-SU(2) symmetry of the Hubbard model. Numerical simulation of the driven expansion dynamics demonstrate that the momentum in which doublons quasicondense can be controlled by the driving amplitude. These results point to new pathways for engineering non-equilibrium condensates in fermionic cold-atom experiments and are potentially relevant to driven solid-state systems.