Temperature-Dependent Dynamics of Endohedral Fullerene Sc2@C80(CH2Ph) Studied by EPR Spectroscopy

Endohedral fullerenes are promising materials for the quantum information and quantum processing due to the unique properties of the electron-nuclear spin system well isolated from the environment inside the fullerene...

Релаксация электронного спина и резонансное охлаждение ядерных спинов в структурах GaAs : Mn

The behavior of the electron spin relaxation time in bulk GaAs layers doped with Mn was studied experimentally. We investigated the dependence of the degree of circular polarization of photoluminescence in transverse and longitudinal magnetic fields. An increase in the relaxation time of the electron spin is found from 25 ns at low pumping power to 400 ns at the threshold pumping power. The effect of resonant cooling of the nuclear spin system by optically oriented electron spins is demonstrated.

Fictitious spin-12 operators and correlations in quadrupole nuclear spin system

The Hamiltonian and the spin operators for a spin 3/2 are represented in the basis formed by the Kronecker productions of the [Formula: see text] Pauli matrices. This reformulation allows us to represent a spin 3/2 as a system of two coupled fictitious spins 1/2. Correlations between these fictitious spins are studied using well-developed methods. We investigate the temperature and field dependences of correlations, such as mutual information, classical correlations, entanglement, and geometric and quantum discords in the fictitious spin-1/2 system describing a nuclear spin 3/2 which is placed in magnetic and inhomogeneous electric fields. It is shown that the correlations between the fictitious spins demonstrate properties which differ from those of real two-spin systems. In contrast to real systems all the correlations between the fictitious spins do not vanish with increasing external magnetic field; at a high magnetic field the correlations tend to their limiting values. Classical correlations, quantum and geometric discords reveal a pronounced asymmetry relative to the measurements on subsystems (fictitious spins) even in a uniform magnetic field and at symmetrical EFG, [Formula: see text]. The correlations depend also on the distribution of external charges, on the parameter of symmetry [Formula: see text]. At [Formula: see text] quantum and geometric discords have finite values in a zero magnetic field. The proposed approach may be useful in analysis of properties of particles with larger angular momentum, can provide the way to discover new physical phenomenon of quantum correlations, and can be a useful tool for similar definitions of other physical quantities of complex systems.