597 research outputs found
Quantum dynamics of a hydrogen-like atom in a time-dependent box: non-adiabatic regime
We consider a hydrogen atom confined in time-dependent trap created by a
spherical impenetrable box with time-dependent radius. For such model we study
the behavior of atomic electron under the (non-adiabatic) dynamical confinement
caused by the rapidly moving wall of the box. The expectation values of the
total and kinetic energy, average force, pressure and coordinate are analyzed
as a function of time for linearly expanding, contracting and harmonically
breathing boxes. It is shown that linearly extending box leads to de-excitation
of the atom, while the rapidly contracting box causes the creation of very high
pressure on the atom and transition of the atomic electron into the unbound
state. In harmonically breathing box diffusive excitation of atomic electron
may occur in analogy with that for atom in a microwave field
Interaction between spin and Abrikosov vortices in doped topological insulators
In the topological superconductor with the nematic superconductivity in
representation, it is possible to have different types of vortices. One is
associated with the vorticity in the particle-hole space and corresponds to the
Abrikosov vortex. Another type corresponds to the vorticity in the spin space
and is called spin vortex. We study the interaction of the Abrikosov vortex
with the spin vortices. We derive the free energy of the sample with the
Abrikosov and the strain-induced spin vortices using the Ginzburg-Landau
approach for the two-component superconducting order parameter. We calculate
the critical strain at which the spin vortex is formed. We show that the spin
vortex and the Abrikosov vortex attract to each other and, as a result, they
have a common core. We show that there are no zero-energy states (Majorana
fermions) localized near the common vortex core of the Abrikosov vortex and the
spin vortex of any type. Possible experimental realization is discussed
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