论文标题
超速费尔米体中时间依赖性杂质的多维光谱
Multidimensional Spectroscopy of Time-Dependent Impurities in Ultracold Fermions
论文作者
论文摘要
我们研究了沉浸在退化的费米气体中的沉重杂质的系统，其中杂质的内部自由度（伪传）在几个不同的时间通过一系列射频（RF）脉冲来操纵。采用功能性决定因素方法，我们对Ramsey Interference-Type对RF脉冲的响应进行了基本精确的计算。这些响应是脉冲之间的多个时间间隔的通用函数，并且可以被视为在时间域中系统的多维（MD）光谱。时间间隔的傅立叶变换给出了频域中的MD光谱，从而提供了有关通过交叉峰的多体相关性和放松的深刻信息，例如，在二维光谱中的非对角线峰。对于常规的一维吸收光谱，这些特征无法访问。我们的方案提供了一种新方法，以使用冷原子中的可访问工具来研究除线性响应方案以外的多体无量化物理。
We investigate the system of a heavy impurity immersed in a degenerated Fermi gas, where the impurity's internal degree of freedom (pseudospin) is manipulated by a series of radiofrequency (RF) pulses at several different times. Applying the functional determinant approach, we carry out an essentially exact calculation of the Ramsey-interference-type responses to the RF pulses. These responses are universal functions of the multiple time intervals between the pulses for all time and can be regarded as multidimensional (MD) spectroscopy of the system in the time domain. A Fourier transformation of the time intervals gives the MD spectroscopy in the frequency domain, providing insightful information on the many-body correlation and relaxation via the cross-peaks, e.g., the off-diagonal peaks in a two-dimensional spectrum. These features are inaccessible for the conventional, one-dimensional absorption spectrum. Our scheme provides a new method to investigate many-body nonequilibrium physics beyond the linear response regime with the accessible tools in cold atoms.
