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In this work bound states for the Aharonov-Casher problem are considered. According to Hagens work on the exact equivalence between spin-1/2 Aharonov-Bohm and Aharonov-Casher effects, is known that the $boldsymbol{ abla}cdotmathbf{E}$ term cannot be neglected in the Hamiltonian if the spin of particle is considered. This term leads to the existence of a singular potential at the origin. By modeling the problem by boundary conditions at the origin which arises by the self-adjoint extension of the Hamiltonian, we derive for the first time an expression for the bound state energy of the Aharonov-Casher problem. As an application, we consider the Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the expression for the harmonic oscillator energies and compare it with the expression obtained in the case without singularity. At the end, an approach for determination of the self-adjoint extension parameter is given. In our approach, the parameter is obtained essentially in terms of physics of the problem.
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We propose the Aharonov-Casher (AC) effect for four entangled spin-half particles carrying magnetic moments in the presence of impenetrable line charge. The four particle state undergoes AC phase shift in two causually disconnected region which can show up in the correlations between different spin states of distant particles. This correlation can violate Bells inequality, thus displaying the non-locality for four particle entangled states in an objective way. Also, we have suggested how to control the AC phase shift locally at two distant locations to test Bells inequality. We belive that although the single particle AC effect may not be non-local but the entangled state AC effect is a non-local one.
We propose an experiment that would produce and measure a large Aharonov-Casher (A-C) phase in a solid-state system under macroscopic motion. A diamond crystal is mounted on a spinning disk in the presence of a uniform electric field. Internal magnetic states of a single NV defect, replacing interferometer trajectories, are coherently controlled by microwave pulses. The A-C phase shift is manifested as a relative phase, of up to 17 radians, between components of a superposition of magnetic substates, which is two orders of magnitude larger than that measured in any other atom-scale quantum system.
Ring structures fabricated from HgTe/HgCdTe quantum wells have been used to study Aharonov-Bohm type conductance oscillations as a function of Rashba spin-orbit splitting strength. We observe non-monotonic phase changes indicating that an additional phase factor modifies the electron wave function. We associate these observations with the Aharonov-Casher effect. This is confirmed by comparison with numerical calculations of the magneto-conductance for a multichannel ring structure within the Landauer-Buttiker formalism.
The Floydian trajectory method of quantum mechanics and the appearance of microstates of the Schr{o}dinger equation are reviewed and contrasted with the Bohm interpretation of quantum mechanics. The kinematic equation of Floydian trajectories is analysed in detail and a new definition of the variational derivative of kinetic energy with respect to total energy is proposed for which Floydian trajectories have an explicit time dependence with a frequency equal to the beat frequency between adjacent pairs of energy eigenstates in the case of bound systems. In the case of unbound systems, Floydian and Bohmian trajectories are found to be related by a local transformation of time which is determined by the quantum potential.
In a recent Letter, Bergsten and co-authors have studied the resistance oscillations with gate voltage and magnetic field in arrays of semiconductor rings and interpreted the oscillatory magnetic field dependence as Altshuler-Aronov-Spivak (AAS) oscillations and oscillatory dependence on gate voltage as the Aharonov-Casher (AC) effect. This Comment shows that Bergsten and co-authors incorrectly identified AAS effect as a source of resistance oscillations in magnetic field, that spin relaxation in their experimental setting is strong enough to destroy oscillatory effects of spin origin, and that the oscillations are caused by changes in carrier density and the Fermi energy by gate, and are unrelated to spin.
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