Title: Cavity Magnonics with Domain Walls in Insulating Ferromagnetic Wires
Abstract: Magnetic domain walls (DWs) are topological defects that exhibit robust low-energy modes that can be harnessed for classical and neuromorphic computing. The quantum nature of these modes, however, has been elusive thus far. In this talk, I will describe how to exploit the interaction between DWs and the extended magnons in ferromagnetic insulating wires to prepare and detect non classical DW quantum states [1]. First, we identify a coupling between the two entities originating from the DW Berry phase modification caused by the excited magnons. Then, using the language of cavity optomechanics [2], we show how to leverage this interaction for DW quantum state preparation via frequency up-conversion of the magnons. Furthermore, we demonstrate that magnons can mediate long-range entangling interactions between distant DWs which could facilitate the implementation of a universal set of quantum gates. Finally, we establish a magnonic input-output framework and show that the DW quantum states can be inferred from magnonic power spectrum measurements. Since such a scheme relies only on the intrinsic degrees of freedom of the ferromagnet, it can be naturally extended to ferrimagnets and antiferromagnets.
[1] Mircea Trif, Dalton Jones, and Yarsoslav Tserkovnyak, “Cavity magnonics with domain walls in insulating ferromagnetic wires” (to appear).
[2] Markus Aspelmeyer, Tobias J. Kippenberg, and Florian Marquardt, “Cavity optomechanics”, Rev. Mod. Phys. 86, 1391 (2014).