In this letter, we analyze the effects of light intensity on reflective ghost imaging with thermal source. We find that the brightness of reflective ghost image can be changed by modulating the light intensity of the source and the splitting ratio of the beam splitter. The signal-to-noise ratio will be improved by increasing the light intensity of the source. More important, we can obtain the reflective ghost image with high image quality by adopting a low light intensity signal beam and a high light intensity reference beam, which is better than the classical optical imaging, because it can reduce the effects of light on the object.

利用弱测量技术研究两量子比特的量子关联动力学演化和转移。有纠缠突然死亡现象产生的非最大纠缠初态经前选择测量操作后，在演化过程中不但能够提高量子关联强度，而且能够缩短甚至消除量子比特纠缠的突然死亡区域；而对于演化中无纠缠突然死亡的非最大纠缠初态，弱测量操作则会降低量子比特间关联强度。对初始处于最大纠缠态的粒子，弱测量操作不能增强粒子间的纠缠但可以优化量子关联中的量子失谐。弱测量在实现量子关联转移时的破坏极小，能够延迟纠缠的衰减，并可使量子纠缠的转移时间提前。另外腔场与量子比特间的耦合强度与系统耗散率的关系决定纠缠原子在腔中动力学演化，表现为马尔可夫和非马尔可夫过程。

考虑初始处于纠缠态的两原子,分别以一定的速率依次通过高Q粒子数场,利用negativity度量纠缠的方法,研究了两原子之间的纠缠演化与原子初态和光场状态的关系,并与两原子同时在腔场时的情况做了比较。发现:当粒子数场为真空场时,两种模型下双原子纠缠度均做周期性演化;当粒子数场为非真空场时,双原子纠缠度都会出现纠缠猝死现象。并进一步研究了该现象随初始纠缠参量θ、粒子数n的变化关系以及与环境(腔场)的纠缠转移问题。