论文标题
多体量子混乱在频道驱动的冷原子中
Many-body quantum chaos in stroboscopically-driven cold atoms
论文作者
论文摘要
在量子混沌系统中,已知频谱形式(SFF)定义为两级光谱相关函数的傅立叶变换,已知遵循随机矩阵理论(RMT),即“坡道”,然后在足够的较晚时间内进行“高原”。最近,我们称之为“ bump”的RMT行为的通用早期偏差被证明存在于随机量子电路中,并且旋转链作为多体量子混沌系统的玩具模型。在这里,我们证明了SFF中的“凸起式 - 板岩”行为的存在,用于许多范式和频道式驱动的1D冷原子模型:(i)Bose-hubbard模型,(ii)旋转$ -1/2 $ bose-hubbard模型,以及(iii)与condensate nontergegrable Spin-$ 1 $ Centensate与Condensate互动或condensal互动。我们发现,多体时间的缩放时间$ t _ {\ textrm {th}} $ - rmt-的发作和凸起振幅对原子数的变化比晶格大小的变化更敏感,而与超精细结构,对称性类别或驾驶协议的选择。此外,$ t _ {\ textrm {th}} $缩放和旋转原子数中的凸起振幅的增加比在1D光学晶格中相互作用的玻色子较慢,这表明了局部性的作用。我们获得了SFF的通用缩放函数,该功能暗示了量子混乱的冷原子系统中凸起政权的幂律行为,并提出了干涉测量方案。
In quantum chaotic systems, the spectral form factor (SFF), defined as the Fourier transform of the two-level spectral correlation function, is known to follow random matrix theory (RMT), namely a 'ramp' followed by a 'plateau' in sufficiently late times. Recently, a generic early-time deviation from the RMT behavior, which we call the 'bump', was shown to exist in random quantum circuits and spin chains as toy models for many-body quantum chaotic systems. Here we demonstrate the existence of the 'bump-ramp-plateau' behavior in the SFF for a number of paradigmatic and stroboscopically-driven 1D cold atom models: (i) Bose-Hubbard model, (ii) spin$-1/2$ Bose-Hubbard model, and (iii) nonintegrable spin-$1$ condensate with contact or dipolar interactions. We find that the scaling of the many-body Thouless time $t_{\textrm{Th}}$ -- the onset of RMT -- , and the bump amplitude are more sensitive to variations in atom number than the lattice size regardless of the hyperfine structure, the symmetry classes, or the choice of driving protocol. Moreover, $t_{\textrm{Th}}$ scaling and the increase of the bump amplitude in atom number are significantly slower in spinor gases than interacting bosons in 1D optical lattices, demonstrating the role of locality. We obtain universal scaling functions of SFF which suggest power-law behavior for the bump regime in quantum chaotic cold-atom systems, and propose an interference measurement protocol.