Magnetic strong coupling in a spin-photon system and transition to classical regime

I. Chiorescu (1) , N. Groll (1) , Sylvain Bertaina (2) , T. Mori , S. Miyashita (3)

1 NHMFL - National High Magnetic Field Laboratory
2 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
3 Department of Physics

We study the energy level structure of the Tavis-Cumming model applied to an ensemble of independent magnetic spins s =1/ 2 coupled to a variable number of photons. Rabi splittings are calculated and their distribution is analyzed as a function of photon number n max and spin system size N. A sharp transition in the distribution of the Rabi frequency is found at n max N. The width of the Rabi frequency spectrum diverges as N at this point. For increased number of photons n max N, the Rabi frequencies converge to a value proportional to n max. This behavior is interpreted as analogous to the classical spin-resonance mechanism where the photon is treated as a classical field and one resonance peak is expected. We also present experimental data demonstrating cooperative, magnetic strong coupling between a spin system and photons, measured at room temperature. This points toward quantum computing implementation with magnetic spins, using cavity quantum-electrodynamics techniques.

Mots clés: numbers: 4250Ct; 7145d; 7545j; 6460i

Domaines: Electrons fortement corrélés [cond-mat.str-el]

I. Chiorescu, N. Groll, Sylvain Bertaina, T. Mori, S. Miyashita. Magnetic strong coupling in a spin-photon system and transition to classical regime. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2010, 82 (2), ⟨10.1103/PhysRevB.82.024413⟩. ⟨hal-01699804⟩