STUDY ON COHERENT-ELECTRON-OSCILLATION DEVICES USING COUPLED-QUANTUM-STRUCTURES

为了实现用于信息处理的新型光电子量子硬件，我们研究了半导体量子结构中量子（原子和电子）波以及激光冷却原子和玻色-爱因斯坦凝聚体在激光场、电场和磁场等外部控制场存在下的相干动力学。得到的主要结果如下：(1)研究了位于等边三角形顶点的三耦合量子点中电子在旋转电场影响下的旋转模式。预测了两种旋转模式；一个是旋转的，电子的旋转方向与旋转电场的方向相同另一个是反旋转的电子的旋转方向与旋转电场的方向相反。(2)预测了当激光脉冲驱动其中一个量子阱中的亚能级跃迁时，耦合量子阱中的量子隧道效应会发生动力学控制。算例表明，采用适当的脉冲间隔和脉冲面积的短脉冲序列，即使在非共振状态之间也可以实现完全的隧道振荡。这种现象可以理解为时域的相位匹配。(3)研究了拉曼激光脉冲通过共同激发态进行光耦合的两种不同阱或同一阱的玻色-爱因斯坦凝聚体的原子居群动力学。对于大的原子间相互作用，在激光脉冲后，几乎所有最初处于其中一个陷阱（或其中一个内部状态）的原子要么完全转移到另一个状态，要么保持在最初占据的状态。最终，原子（居群）永远不会同时分布到两种凝析态。

IN ORDER TO IMPLEMENT THE NEW OPTO-ELECTRONICS QUANTUM HARDWARES FOR INFORMATION PROCESSING, WE HAVE INVESTIGATED THE COHERENT-DYNAMICS OF THE QUANTUM (ATOM AND ELECTRON) WAVE IN THE SEMICONDUCTOR QUANTUM STRUCTURES AS WELL AS LASER-COOLED ATOMS AND THE BOSE-EINSTEIN CONDENSATES IN THE PRESENCE OF EXTERNAL CONTROL FIELDS SUCH AS LASER FIELD, ELECTRIC FIELD, AND MAGNETIC FIELD.THE MAIN RESULTS OBTAINED ARE AS FOLLOWS :(1) WE HAVE STUDIED THE ROTATIONAL MODE OF THE ELECTRONS IN THREE-COUPLED QUANTUM DOTS, WHICH ARE LOCATED AT THE APEXES OF AN EQUILATERAL TRIANGLE, UNDER THE INFLUENCE OF A ROTATIONAL ELECTRIC FIELD.TWO ROTATIONAL MODES ARE PREDICTED ; ONE IS THE COROTATIONAL ONE WHERE THE ELECTRONS ROTATE THE SAME DIRECTION AS THE ROTATING ELECTRIC FIELD AND THE OTHER IS THE COUNTER-ROTATIONAL ONE WHERE THE ELECTRONS ROTATE THE OPPOSITE DIRECTION TO THE ROTATING ELECTRIC FIELD.(2) DYNAMICAL CONTROL OF QUANTUM TUNNELING IN A COUPLED QUANTUM WELL HAS BEEN PREDICTED TO OCCUR WHEN LASER PULSES DRIVE SUBLEVEL TRANSITIONS IN ONE OF THE WELLS.IT WAS SHOWN FOR AN EXAMPLE THAT COMPLETE TUNNELING OSCILLATIONS CAN BE REALIZED, EVEN BETWEEN THE NONRESONANT STATES, BY MEANS OF A TRAIN OF SHORT PULSES WITH APPROPRIATE PULSE INTERVAL AND PULSE AREA.THIS PHENOMENON CAN BE UNDERSTOOD AS THE PHASE MATCHING IN TIME-DOMAIN.(3) WE HAVE INVESTIGATED ATOMIC POPULATION DYNAMICS OF TWO BOSE-EINSTEIN CONDENSATES THAT ARE IN DIFFERENT TRAPS OR IN THE SAME TRAP AND ARE OPTICALLY COUPLED THROUGH A COMMON EXCITED STATE BY RAMAN LASER PULSES.FOR LARGE INTERATOMIC INTERACTIONS, ALMOST ALL OF THE ATOMS THAT ARE INITIALLY IN ONE OF THE TRAPS (OR ONE OF THE INTERNAL STATES) ARE EITHER COMPLETELY TRANSFERRED INTO THE OTHER STATE OR STAY IN THE INITIALLY OCCUPIED STATE AFTER THE LASER PULSES.EVENTUALLY, THE ATOMS (POPULATIONS) ARE NEVER DISTRIBUTED TO BOTH CONDENSATE STATES AT THE SAME TIME.