Nuclear level mixing-induced interference in FeCO₃

Abstract

We present a detailed description and a consistent explanation of the transparency observed in the Mössbauer absorption spectra at a nuclear level mixing in FeCO3. We develop a model for scattering in this nuclear Λ system in a Maxwell–Schrödinger approach, taking into account multiple scattering and polarization effects. It is shown that the level mixing scheme not only yields an expected Stark splitting, but, due to the unequal relaxation rates and transition strengths, an additional interference term is present. Therefore, this scheme is equivalent to the Λ scheme considered for EIT in quantum optics. The interference in the absorption of the gamma radiation can be destructive, leading to a partial transparency, but can also be constructive. Both types of interference are present in the observed spectra.

Magnetic and structural properties of FeCO3 at high pressures

“…The electromagnetically induced transparency phenomenon via unusual nuclear-level anticrossing scheme discovered in siderite for gamma rays makes it prospective for applications in the field of nuclear quantum optics [3,4]. In addition, iron bearing carbonates are considered to play an important role in the deep carbon cycle of the Earth, attracting significant interest to studies of physical properties of such compounds under variation of thermodynamics parameters [5,6].…”

Towards more relaxed conditions for a gamma‐ray laser: Methods to realize induced transparency for nuclear resonant gamma radiation

“…The left part of Fig. 7 shows a close-up of the experimental spectra at the temperature where the levels cross, again in the perpendicular and parallel geometries [31]. In Fig.…”

“…ciable effect, it is necessary to have unequal relaxation rates: the decay rate, Γ 31 , of the coherence ρ 31 , must be much faster than the decay rate, Γ 21 , of the coherence ρ 21 , which becomes long-lived compared to the coherence ρ 31 .…”

“…Fig. 9 shows the new fits in the parallel and perpendicular geometry [31], although it has to be mentioned that the fits are still not perfect. This is possibly due to some distribution of the hyperfine fields related to impurities, which leads to a distribution in isomer shifts as well as in quadrupole interactions, as has been mentioned before.…”

“…The absorber was prepared from the mineral siderite, which is FeCO 3 in which 57 Fe occurs with its natural abundance, hence nonenriched. More information on the absorber can be found in [30] and [31]. The effective thickness parameter β, a dimensionless quantity, defined by β = N 0 fσ 0 d, where N 0 is the number of resonant nuclei/cm 3 , f is the recoilfree fraction, σ 0 is the maximum cross-section evaluated on resonance, and d is the actual thickness of the sample (e.g.…”