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A philosophically consistent axiomatic approach to classical and quantum mechanics is given. The approach realizes a strong formal implementation of Bohr's correspondence principle. In all instances, classical and quantum concepts are fully parallel: the same general theory has a classical realization and a quantum realization. Extending the ''probability via expectation'' approach of Whittle to noncommuting quantities, this paper defines quantities, ensembles, and experiments as mathematical concepts and shows how to model complementarity, uncertainty, probability, nonlocality and dynamics in these terms. The approach carries no connotation of unlimited repeatability; hence it can be applied to unique systems such as the universe. Consistent experiments provide an elegant solution to the reality problem, confirming the insistence of the orthodox Copenhagen interpretation on that there is nothing but ensembles, while avoiding its elusive reality picture. The weak law of large numbers explains the emergence of classical properties for macroscopic systems.

We report on the magneto-optical study of spin polarized energetic fine structures for exciton complex in single CdSe quantum dot (QD) by using micro- photoluminescence (micro-PL) spectroscopy. The zero-field splitting of exciton luminescence peak arisen from the anisotropic exchange interaction of carriers in the QDs was observed. The g-factors for exciton and negatively-charged exciton, i.e. trion in a single QD were determined by fitting the magnetic field dependence of the corresponding PL peaks. By exciting the single QD with circularly polarized light of σ- and σ+ polarization, the spin-up and spin-down trions were selectively generated. The ratio, τ/τ_sf, of the exciton lifetime and the time constants for the spin-flipping process of trion in a single QD was estimated to be 0.13, which implies a long spin-lifetime in single CdSe QD.

The superfine structure of Bose-Einstein condensate of alkali atoms due to the spin coupling have been investigated in the mean field approximation. In the limit of large number of atoms, we obtained the analytical solution for the fully condensed states and the states with one-atom excited. It was found that the energy of the one-atom excited state could be smaller than the energy of the fully condensed state, even two states have similar total spin.

This article reviews steady-state spin densities and spin currents in materials with strong spin-orbit interactions. These phenomena are intimately related to spin precession due to spin-orbit coupling, which has no equivalent in the steady state of charge distributions. The focus will initially be on effects originating from the band structure. In this case, spin densities arise in an electric field because a component of each spin is conserved during precession. Spin currents arise because a component of each spin is continually precessing. These two phenomena are due to independent contributions to the steady-state density matrix, and scattering between the conserved and precessing spin distributions has important consequences for spin dynamics and spin-related effects in general. In the latter part of the article, extrinsic effects such as skew scattering and side jump will be discussed, and it will be shown that these effects are also modified considerably by spin precession. Theoretical and experimental progress in all areas will be reviewed.

We show that the electron–positron annihilation process ending with the creation of two gamma photons (with right- and left-hand circular helicity) can be explained in terms of the current loop model. We first show that both electron and positron (which are spin 1/2 particles) carry an intrinsic flux quantum of ±Φ₀/2 even in the absence of an external magnetic field. By using the conservation of the magnetic flux quanta for collisions, we then argue that photon also carries a magnetic flux quantum of ±Φ₀ = ±(hc/e) with itself along the propagation direction, where the (+) sign corresponds to the right-hand helicity and (-) one to the left-hand one.

We present tilted-field experiments on a bilayer electron system at ν_T = 1 with negligible tunneling and demonstrate that the spin degree of freedom plays a decisive role in the ground-state phase diagram of the system. We observe that the phase boundary separating the incompressible quantum Hall state and a compressible state at d/ℓ_B = 1.90 (d: interlayer distance, ℓ_B: magnetic length) in a perpendicular field shifts to higher densities with tilt until it saturates at d/ℓ_B = 2.33. We develop a model describing the energies of the competing phases and show that the observed shift of the phase boundary reflects the spin-polarization dependence of the Coulomb and Zeeman energies of the compressible state. A new phase diagram as a function of d/ℓ_B and the Zeeman energy is established and its implications as to the nature of the phase transition are discussed.

We develop a quantum theory to deal with the coherent magnon excitation in monolayer magnetic nanodots induced by a circularly polarized light. In our theoretical model, the exchange interaction, the magnetic dipole interaction and the light-matter interaction are all taken into account and an effective dynamic equations governing the magnon excitation is derived by a continuum approximation. Our theoretical model shows that the helicity of light and the magnetic dipole interaction govern the magnon excitation and result in the occurrence of various patterns for the spin z-component distribution. We present a scheme to manipulate the single-mode magnon excitation by properly tuning the light frequency.

The configurations, electronic and spin of the FeO–HCNO clusters are calculated at the PW91 level. The results show that the Fe atom of FeO molecule prefers to interact with the O and N atoms of HCNO molecule and the corresponding FeO–HCNO cluster possesses highest kinetic stability. For this lowest-energy FeO–HCNO clusters, the 2p3d orbitals of O and N atoms obtain more electrons than the 2s orbital of the two atoms loss. In the isomer (6) which O atoms occur at the same ends of the FeO and HCNO fragments, it leads to increase the dipole moment. As for the axisymmetric isomer (1), the total spin is zero due to upward spin is perfectly offset by the downward spin.

In this review, we present the recent discovery and confirmation of a new negative molecular ion, the ${\text{CH}}_4^{-}$ anion. The experimental identification of this high-spin exciplex was difficult because it overlaps with the negative oxygen ion commonly present as a contaminant in vacuum systems and with the same mass-spectrometric signature. Born–Oppenheimer molecular dynamics (BOMD) simulations finally reveal that this anion is a quartet ($S=3/2$) metastable species, which leads to the formation of a molecular (${\text{CH}}_2:H_2{)}^{-}$ excited complex.