Probing the Correlated Spin-Dynamics of Ultracold Atoms: Magnetic and Polaronic Properties

Georgios Koutentakis , Hamburg University
In this talk I will go through two topics relevant for ultracold experiments with spinor atoms. First I will outline the main facets of ferromagnetism emerging in one-dimensional systems. Here, by exploring the dynamics of few-body systems [1, 2], we were able to expose and characterize the underlying ferromagnetic (Hund) and antiferromagnetic (Anderson) spin-exchange mechanisms. The competition of these spin-interactions under certain conditions results in the system exhibiting distinctly ferromagnetic behavior. Our results provide a generalization to the well-enstablished Stoner model of ferromagnetism and might be relevant for studies in higher dimensional setups. Subsequently, I will analyze the dynamics of the Bose polaron in one-dimension exhibiting the phenomenon of the temporal orthogonality catastrophe [3] and provide spectroscopic means for its identification [3, 4]. This phenomenon is manifested when strong repulsive bath-impurity interactions are switched on in a rapid manner, resulting to a rapid evolution of the system state towards a configuration orthogonal to the initial one. The occurrence of the temporal orthogonality catastrophe signifies the dynamical decay of the Bose polaron and the tendency of the system to an eigenstate thermalized state. [1] G. M. Koutentakis, S. I. Mistakidis, and P. Schmelcher, New J. Phys. 21, 053005 (2019). [2] G. M. Koutentakis, S. I. Mistakidis, and P. Schmelcher, New J. Phys. 22, 063058 (2020). [3] S. I. Mistakidis, G. C. Katsimiga, G. M. Koutentakis, Th. Busch, and P. Schmelcher, Phys. Rev. Lett. 122, 183001 (2019). [4] S. I. Mistakidis, G. C. Katsimiga, G. M. Koutentakis, Th. Busch, and P. Schmelcher, Phys. Rev. Research 2, 033380 (2020).
Many-Body Theory
29 Sep 2021, 14:15
Institut für Theoretische Physik, Online

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