The present study highlights free Induction Decay, Spin Echo
Signals, Pure Superradiance, and Rabi Oscillations from Spin Triplet States in
Zero-Constant Magnetic Field.
Anisotropic dynamics of the spin-triplet states (STSs) in single
crystals with the zero fields splitting (ZFS) of their levels by the axially
asymmetric Hamiltonian is investigated in zero constant magnetic fields (ZF)
under the action of the canonically oriented varying magnetic fields. The
equations of motion for single transition operators (STOs) corresponding to the
definite transition of ZFS are derived. The obtained equations written in terms
of one averaged equation for STO vector appeared to be a particular case (for
STS) of the universal equation of Feynman et al, which is valid for any kind of
perturbation affecting only two levels of any quantum mechanical system. As
well as that, our equation is analogous to the Bloch equation without decay for
the usual magnetization components of the Zeeman system in a constant magnetic
field and a transverse to its varying field. However, the motion of the
observable macroscopic sample magnetization, which follows from our equations,
has quite a different character than that of the motion of the STO vector.
Here, in terms of this magnetization the signals of the free induction decay,
of the two-pulse spin echo, the parameters of the pure superradiance and Rabi
oscillations are calculated in ZF. Rabi oscillations observable both in the
frequency domain and in the time domain are investigated classically in the
linear approximation. At that, a variety of two-level systems (spin
transitions, magnons, atoms, molecules, excitons and so on) can act as
emitters. The “fork” effect is predicted for normal decay at the decreasing of
the value of the spin-photon coupling, in contrast to the known “fork” effect
of normal frequencies with increasing spin-photon coupling.
Author
(s) Details
Nathalie
P. Fokina
Institute 'Talgha', Georgian Technical University, 0186 Tbilisi,
Georgia.
Maia O.
Elizbarashvili
Vladimir Chavchanidze Institute of Cybernetics, Georgian Technical
University, 0186 Tbilisi, Georgia.
Please see the book here:- https://doi.org/10.9734/bpi/srnta/v4/2077
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