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Theoretical calculation of electronic energy levels of an asymmetric InAs/InGaAs/GaAs quantum-dots-in-a-well (DWELL) structure for infrared photodetectors is performed in the framework of effective-mass envelope-function theory Our calculated results show that the electronic energy levels in quantum dots (QDs) increase when the asymmetry increases and the ground state energy increases faster than the excited state energies. Furthermore, the results also show that the electronic energy levels in QDs decrease as the size of QDs and the width of quantum well (QW) in the asymmetric DWELL structure increase. Additionally, the effects of asymmetry, the size of QDs and the width of QW on the response peak of asymmetry DWELL photodetectors are also discussed.

The Navier–Stokes equations for slip flow between two very closely spaced parallel plates are transformed to an ordinary differential equation based on the pressure gradient along the flow direction using a new similarity transformation. A powerful easy-to-use homotopy analysis method was used to obtain an analytical solution. The convergence theorem for the homotopy analysis method is presented. The solutions show that the second-order homotopy analysis method solution is accurate enough for the current problem.

We study the Bloch oscillations of two-component Bose–Einstein condensates trapped in spin-dependent optical lattices. The influence of the intercomponent atom interaction on the system is discussed in detail. Accelerated breakdown of the Bloch oscillations and revival phenomena are found respectively for the repulsive and attractive case. For both the cases, the system will finally be set in a quantum self-trapping state due to dynamical instability.

Radiation pressure and laser cooling of a moving three-level ladder-type atom in bichromatic travelling fields are considered. The dependence of the force on parameters such as detunings, Rabi frequencies and spontaneous decay rates is calculated numerically and shown graphically and analytical expressions for the force are obtained for some special parameter values. It is shown that the radiation pressure shows Doppler-shifted resonance peaks resulting respectively from one-photon and two-photon transitions. Using the present scheme, Doppler cooling of sodium exploiting the 3 2S1/2–32P3/2–32D5/2 cascade transitions is investigated. It is found that temperatures lower than the Doppler limit can be achieved.