Asymmetric double well, quantum

The purpose of this work is to demonstrate that the techniques of quantum control, which were developed originally to study atoms and molecules, can be applied to the solid state. Previous work considered a simple example, the asymmetric double quantum well (ADQW). Results for this system showed that both the wave paeket dynamics and the THz emission can be controlled with simple, experimentally feasible laser pulses. This work extends the previous results to superlattices and chirped superlattices. These systems are considerably more complicated, because their dynamic phase space is much larger. They also have potential applications as solid-state devices, such as ultrafast switches or detectors. 

Figure 11 Conduction subband of the asymmetric double quantum well.

Figure 5. Quantum dynamics for an asymmetric double well under coherent or thermal preparations. Vertical energy separation between the two wells (Ae) is 300 cm1, o> = 100...

This section considers a single asymmetric double-well potential. At low temperatures a quantum mechanical description is necessary, and only the lowest energy eigenstates will be relevant. If the energy asymmetry of the wells is not too great then it will be sufficient to describe the problem in terms of a two-state basis, where the two states are localized in each of the two wells of the potential. These two states compose the TLS. 

We propose an asymmetric double AlGaAs/GaAs quantum well strueture with a eommon continuum to generate a large cross-phase modulation (XPM). The basie idea is to combine resonant tuimeling induced constructive interference in eross-phase modulation (XPM) and tunneling-induced transparency (TIT). The band structure is shown in Fig. 11, whieh is designed with small electron decay rates, which can reduce the linear absorption effectively. A... 

The spin-boson model can be motivated in terms of the physical problan of a quantum particle (e.g., an electron, muon, or proton) tunneling in an asymmetric double well (Figure 11.4). The relevant energy scales are the asymmetry he, tunneling HAq, and thermal k T, which can be all comparable but are much smaller than the barrier height Eq. Under this circumstance, the dynamics of the quantum particle moving in the double well can be described by what we shall refer to as the subsystem Hamiltonian... 

---