Transient nutation of dressed spin states of E′1 centers in a quartz crystal

Relaxation, decoherence, and steady-state population inversion in qubits doubly dressed by microwave and radiofrequency fields

“…In such a case the density matrix is The predicted frequencies of the Rabi oscillations between the doubly dressed states were confirmed experimentally [10,12,19] including the Bloch-Siegert effect [11,18,35]. The amplitude of the Rabi oscillations at each frequency is strongly dependent on the RF field phase.…”

“…The multiphoton transitions between the doubly dressed states in the coupled "qubit-bichromatic field" system have been observed in spectral and time-resolved experiments. Doubly dressed states of qubits have been studied in a wide range of physical objects, including, among others, electron and nuclear spins [10,11,13], quantum dots [14,15], superconducting qubits [16], and cold atoms [17]. The splitting of each peak of the initial Mollow triplet into three new ones has been demonstrated at the continuous-wave optical bichromatic excitation of two-level atoms [9].…”

Effective field and the Bloch-Siegert shift at bichromatic excitation of multiphoton EPR

“…In view of this circumstance, a multilevel dynamical quantum system with controllable properties can be created on the basis of the two-level system. Analysis of the dynamics of the dressed spin systems opens new perspectives for developing methods in order to narrow spectral lines, to separate overlapping spectra, and to increase the existence time of coherent spin states.In pulsed EPR experiments based on the simultaneous absorption or emission of several photons with noticeably different frequencies, e.g., microwave and RF radiation, two-and three-photon electron spin echo [1], two-photon nutation [7], as well as RF-fieldinduced transparency [3] and nutation on dressed states [4,5], were observed. Owing to the small amplitude of the effective field (effective Rabi frequency) of multiphoton transitions, as well as to the presence of inhomogeneous line broadening in real systems, difficulties remain both in direct observation of the dynamics of these transitions and in its quantitative interpretation on the basis of adequate theoretical approaches.…”

“…In pulsed EPR experiments based on the simultaneous absorption or emission of several photons with noticeably different frequencies, e.g., microwave and RF radiation, two-and three-photon electron spin echo [1], two-photon nutation [7], as well as RF-fieldinduced transparency [3] and nutation on dressed states [4,5], were observed. Owing to the small amplitude of the effective field (effective Rabi frequency) of multiphoton transitions, as well as to the presence of inhomogeneous line broadening in real systems, difficulties remain both in direct observation of the dynamics of these transitions and in its quantitative interpretation on the basis of adequate theoretical approaches.…”

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In view of the possibilities for changing the energy states of the quantum state with external electromagnetic fields and its interaction with the environment, interest in studying the dynamics of multiphoton processes in nonlinear optics, NMR and EPR, has increased recently [1][2][3][4][5][6][7][8]. In two-level spin systems, there are no real intermediate levels, and "dressed" spin systems formed by external electromagnetic fields can serve as intermediate levels.

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