纠缠态原子与相干光场作用的量子信息保真度

研究了初始处于纠缠态的双原子与相干光场的相互作用。结果表明,不同的失谐量和初始平均光子数使得系统、原子和光场的量子信息保真度发生改变。     

中性原子量子计算研究进展

相互作用可控、相干时间较长的中性单原子体系具备在1 mm2的面积上提供成千上万个量子比特的规模化集成的优势,是进行量子模拟、实现量子计算的有力候选者.近几年中性单原子体系在实验上取得了快速的发展,完成了包括50个单原子的确定性装载、二维和三维阵列中单个原子的寻址和操控、量子比特相干时间的延长、基于里德伯态的两比特量子门的实现和原子态的高效读出等,这些工作极大地推动了该体系在量子模拟和量子计算方面的应用.本文综述了该体系在量子计算方面的研究进展,并介绍了我们在其中所做的两个贡献:一是实现了"魔幻强度光阱",克服了光阱中原子退相干的首要因素,将原子相干时间提高了百倍,使得相干时间与比特操作时间的比值高达105;二是利用异核原子共振频率的差异建立了低串扰的异核单原子体系,并利用里德伯阻塞效应首次实现了异核两原子的量子受控非门和量子纠缠,将量子计算的实验研究拓展至异核领域.最后,分析了中性单原子体系在量子模拟和量子计算方面进一步发展面临的挑战与瓶颈.     

Doppler-free spectroscopy of rubidium atoms driven by a control laser

A scheme of Doppler-free spectroscopy is experimentally demonstrated with a co-propagating control laser locking to an atomic hyperfine transition, and the differential transmission of the probe and the reference laser is detected. Crossover resonances are eliminated by selecting the class of atoms with zero velocity in the direction of beam propagation. In addition, the sub-Doppler spectrum experiences optical gain compared to the conventional saturated-absorption spectrum as a result of optical pumping.     

Bohmian mechanics to high-order harmonic generation

This paper introduces Bohmian mechanics (BM) into the intense laser-atom physics to study high-order harmonic generation. In BM, the trajectories of atomic electron in an intense laser field can be obtained with the Bohm--Newton equation. The power spectrum with the trajectory of an atomic electron is calculated, which is found to be irregular. Next, the power spectrum associated with an atom ensemble from BM is considered, where the power spectrum becomes regular and consistent with that from quantum mechanics. Finally, the reason of the generation of the irregular spectrum is discussed.     

Production and guidance of pulsed atomic beams on chip

We demonstrated two experimental methods of producing and guiding pulsed atomic beams on chip. One is to trap atoms first in a U-type magneto-optical trap on the chip, then transfer them to the magnetic guide field and push them simultaneously by a continuous force from the power imbalance of the magneto-optical trap laser beams hence the pulsed cold atom beams are produced and move along the magnetic guide to the destination. The other is to trap atoms directly by a H-type magneto-optical trap, then push them to make them move along the magnetic guide field, thus high rate cold atom beams can be produced and guided on the chip.     

光腔衰荡技术与高灵敏吸收探测

腔衰荡光谱技术是一种新兴的主灵敏吸收光谱探测技术,已经被广泛地应用于原子、分子、团簇等吸收光谱的测量,且可实现10^-6－10^-14cm^-1量级吸收的测量,文章综述了腔衰荡光谱技术的发展及在吸收光谱探测上的应用。     

含原子运动的Jaynes-Cummings模型中的量子态保真度

研究了相干光场作用下的含原子运动的Jaynes-Cummings模型中体系量子态保真度,讨论了不同的原子初态条件下,原子的运动和场模结构对体系中的量子态保真度的影响。结果表明：在一定的条件下,原子运动的速度和场模结构参数可调制相互作用体系的量子态保真度。     

无耗散介观电感耦合电路的库仑阻塞和电荷的量子效应

基于介观电路中电荷应是量子化的这一基本事实,给出了介观电感耦合电路的量子理论和库仑阻塞条件,并讨论了该介观电感耦合电路的量子涨落. 关键词： 介观电路 电感耦合 电荷的不连续性 库仑阻塞 量子涨落     

Q变形非简谐振子广义奇偶相干态的高阶压缩特性

给出了Q变形的非简谐振子广义奇偶相干态的完备性证明,并且研究了它们的高阶压缩特性.结果表明,它们可组成一个完备的Hilbert空间,且均可呈现奇数阶压缩效应.     

两个正交子能级的V型三能级系统的粒子数振荡特性

研究了线偏振脉冲光场激发下,半导体量子点中两个正交子能级上的粒子数振荡特性.利用旋转波近似方法给出了共振激发和无衰减时粒子数运动方程的解析解.引入了该系统的等效跃迁偶极矩和等效脉冲面积，并给出了其关系表达式.理论分析表明，该体系中的子能级上粒子数振荡的振幅和频率都可以通过改变激发场的偏振角和系统的初态条件进行调控. 关键词： Rabi振荡 旋转波近似 三能级系统