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

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 nmax and spin system size N. A sharp transition in the distribution of the Rabi frequency is found at nmax N. The width of the Rabi frequency spectrum diverges as N at this point. For increased number of photons nmax N, the Rabi frequencies converge to a value proportional to nmax. 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.

[1]  J. Cirac,et al.  Quantum State Transfer and Entanglement Distribution among Distant Nodes in a Quantum Network , 1996, quant-ph/9611017.

[2]  M. S. Skolnick,et al.  Vacuum rabi splitting in semiconductor microcavities with applied electric and magnetic fields , 1995 .

[3]  Brunel,et al.  DPPH as a Standard for High-Field EPR , 1997, Journal of magnetic resonance.

[4]  S. Girvin,et al.  Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics , 2004, Nature.

[5]  Stanley,et al.  Vacuum-field Rabi splitting in the presence of inhomogeneous broadening: Resolution of a homogeneous linewidth in an inhomogeneously broadened system. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[6]  K. Vahala,et al.  Observation of strong coupling between one atom and a monolithic microresonator , 2006, Nature.

[7]  E. Jaynes,et al.  Comparison of quantum and semiclassical radiation theories with application to the beam maser , 1962 .

[8]  D. Loss,et al.  Spin-electric coupling in molecular magnets. , 2008, Physical review letters.

[9]  G. Agarwal.  Vacuum-Field Rabi Splittings in Microwave Absorption by Rydberg Atoms in a Cavity , 1984 .

[10]  C. Piermarocchi,et al.  Microcavity polaritons in disordered exciton lattices , 2008, 0802.3184.

[11]  F. W. Cummings,et al.  Exact solution for spontaneous emission in the presence of N atoms , 1983 .

[12]  Carmichael,et al.  Anharmonicity of the vacuum Rabi peaks in a many-atom system. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[13]  J. Timonen,et al.  Exact solution of generalized Tavis - Cummings models in quantum optics , 1996 .

[14]  Jun Ye,et al.  Real-time cavity QED with single atoms , 1998, Technical Digest. Summaries of Papers Presented at the International Quantum Electronics Conference. Conference Edition. 1998 Technical Digest Series, Vol.7 (IEEE Cat. No.98CH36236).

[15]  Coherent manipulation of electron spins up to ambient temperatures in Cr5+ (S = 1/2) doped K3NbO8. , 2007, Physical review letters.

[16]  J. Raimond,et al.  Observation of Self-Induced Rabi Oscillations in Two-Level Atoms Excited Inside a Resonant Cavity: The Ringing Regime of Superradiance , 1983 .

[17]  Jens Koch,et al.  Nonlinear response of the vacuum Rabi resonance , 2008, 0807.2882.

[18]  N. Dalal,et al.  Entrapment of magnetic microcrystals for on-chip electron spin resonance studies , 2009, 0908.3038.

[19]  Joan P. Marler,et al.  Collective strong coupling with ion Coulomb crystals in an optical cavity , 2009, CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference.

[20]  R. Dicke.  Coherence in Spontaneous Radiation Processes , 1954 .

[21]  A. Wallraff,et al.  Climbing the Jaynes–Cummings ladder and observing its nonlinearity in a cavity QED system , 2008, Nature.

[22]  M. Flatt'e,et al.  Strong Field Interactions between a Nanomagnet and a Photonic Cavity , 2009, 0907.3926.