Micromagnets for novel qubits for quantum computation

One of the challenges in realizing scalable quantum computing is designing hardware that can store and manipulate quantum information at high rates. Superconducting qubits have a number of advantages, but their operational temperature is tens of mK[1]. In this work, we investigate an alternative platform for solid-state qubits based on magnons. The proposed magnetic qubit stores quantum information in the Kittel mode, which is a uniform magnon mode. The anharmonicity required to energetically isolate the qubit states is obtained through a magnetic anisotropy[2], which depends strongly on the boundary conditions (shape), strain and crystalline symmetries. The magnitude of these anisotropies can be quite large, allowing for a highly tunable system. We present calculations of the magnon spectrum in the presence of various forms of anisotropy, and analyze the dependence of non-linear magnon spectrum on the anisotropy strength. In particular, we apply our calculations to Yttrium Iron Garnet[3] and Barium Ferrite[4] materials.

1.P. Krantz, M. Kjaergaard, F. Yan, T. P. Orlando, S. Gustavsson, W. D. Oliver. Appl. Phys. Rev.1 June 2019; 6(2).

2.D. Stancil, A. Prabhakar. Spin Waves theory and Applications.

3.Vladimir Cherepanov, Igor Kolokolov, Victor L'vov. Physics Reports,Volume 229, Issue 3.

4.Robert C. Pullar,Hexagonal ferrites. Progress in Materials Science,Volume 57, Issue 7.