四模光力学、腔隧穿诱导透明和热光交叉克尔效应的研究

发布时间：2018-07-08 15:12

本文选题：耗散控制设计 + 后选择弱测量　；参考：《吉林大学》2017年博士论文

【摘要】：量子关联虽然导致量子态的各种创新的应用,但是也对环境噪音的反应非常敏感。在常规的量子信息处理和各种量子技术中,量子态的制备需要隔绝外界的噪音。虽然在这个方向上的努力已经导致了单粒子或少粒子量子态的精确制备和控制,但是对于复杂的量子系统的制备和控制依然困难。在这种主流的研究思路之外,两种非常规的量子态制备和量子信息处理方式在最近的十年内开始得到更多人的关注。一是耗散控制设计的观念,一是弱作用过程的研究。耗散控制设计考虑把系统外的环境也看作一种资源,用来设计稳定的量子态。虽然有噪音的影响,我们依然可以通过耗散通路的设计,获得纯的纠缠态和具有高度量子关联的量子态。这些年,这个领域的基本想法和关键机制已经被广泛的讨论,并且取得了显著的成功。在弱作用过程下,作用的时间短暂,作用的强度非常弱,导致量子态的变化也非常小,但是也使得耗散过程可以被忽略,使得制备的量子态纯度很高。一种弱作用过程加后选择的想法最近得到了很多关注,称为后选择弱测量。这种观念可以看成是在传统的标准测量方案的基础上加上后选择。但是到了今天,这种观念已经突破了测量的范畴,成为量子态制备和精密测量的一个重要方案。在本论文中,我们对耗散控制设计在光力学系统中的应用做了非常有意义的探讨,我们利用腔和遂穿诱导透明设计了两种性能良好的量子器件,并且对热态的后选择问题做了开创性的研究。通过这些研究,可以看出耗散控制设计和后选择弱测量尤其非常独特的量子系统制备和控制的优点。光力学系统已经成为了实验量子光学领域的一个热点领域,也激发了许多原创性的理论研究。由于力学振子系统是一个宏观系统,所以它所能产生的量子关联对于我们理解各种量子基础问题尤为重要。在光力学系统中产生纠缠甚至强纠缠引起了很多人的关注。在本文中,我们用耗散控制设计的观念讨论了一个四模光力学系统的稳态纠缠问题。基于以前的文章中讨论问题的思路,我们首次把耗散控制设计的思想用到常温下的光力系统。在已有的工作中,光力学系统的两体纠缠的对数负性在零温时小于0.7,在常温时根本没有。王颖丹等人的工作给出产生强纠缠的方法,但是他们的工作是在零温下讨论的。我们发现,该系统在常温下也可以获得显著的纠缠,这与以前的光力学纠缠的工作是非常不同的。而且纠缠随着温度升高的变化方式也和以前的研究区别很大。同时,这个系统也是量子力学无关子空间的一个典型案例。随后我们利用同样的四模光力学系统讨论了不同波长的相干光转移的问题。在不同的频率光之间转移信息是量子网络中的基本问题。在现有的方案中,基于光力学系统的量子态转移如果要获得高的转换效率,需要两个目标腔模的驱动光的强度较大,同时也要求两个腔模的耗散几乎相等。这一方面不利于调控,过强的驱动光会导致力学振子的加热,破坏转换效率,另一方面对于两个腔的设计要求较高。我们首次提出了蓝带边驱动的耗散控制设计的想法。虽然多了一个控制模式,却可以使得相干光转移的耦合强度极大的降低,并且两个目标腔的耗散可以非常不同。尤为重要的,在这里我们揭示了模式消除的想法,可以用到许多其他的量子控制问题中。腔既可以增大也可以减少量子系统的耗散,同时可以极大的增强光与量子系统的耦合强度。而隧穿诱导透明就是设计一个共同的耗散通道,使得两个临近的量子态模式发生干涉,导致透明现象。在本文中,我们同时用这两种方法设计了两种量子器件,都是作用于中红外区的,一种可以延迟光传播的时间,另一种可以对两种频率的光进行开关控制。这两种设计都已经申请专利。后选择弱测量从一出现就引起了广泛的争议,但是其独特的弱作用反常放大能力得到了认可,并且被广泛研究。在现有的工作中,利用后选择弱测量来放大克尔介质中的单光子非线性,这个想法最近得到了极大的发展。但是在现有的工作中,他们只是讨论了相干光作为探针的现象。在我们的工作中,我们用一个热态指针来探究单光子交叉克尔效应,做了非常详细的讨论,我们发现热态指针和相干光指针的放大现象非常不同,热态指针的放大效果更加显著。我们把弱效应推广到热态指针诱导的强效应上。我们发现,对于强效应,传统弱值解释是不成立的。同时,我们也给出了后选择诱导的缩小效应和大概率的放大现象。这些结论都超出了以前的研究范围。热光交叉克尔效应进一步揭示出后选择弱放大的虚放大效应是一种纯粹的经典效应,并且和最近的平衡弱测量技术结合起来,我们给出了虚放大的一般机制。
[Abstract]:Although quantum correlation leads to a variety of innovative applications of quantum states, it is also very sensitive to the response of environmental noise. In conventional quantum information processing and various quantum technologies, the preparation of Quantum States needs to isolate outside noise. Although efforts in this direction have led to the precise preparation of single particles or small particles of quantum state. And control, but the preparation and control of complex quantum systems is still difficult. In addition to this mainstream research idea, two non conventional quantum state preparation and quantum information processing methods have been paid more attention in the last ten years. One is the concept of dissipative control design, one is the study of the weak action process. The system design considers the environment outside the system as a resource to design a stable quantum state. Although there is noise, we can still obtain a pure entangled state and a highly quantum connected quantum state through the design of a dissipative path. These years, the basic ideas and key mechanisms in this field have been widely discussed. In the process of weak action, the time of the action is short and the strength of the action is very weak, and the change of the quantum state is very small, but the dissipative process can be ignored and the purity of the quantum state is very high. The idea of adding after the weak action process has recently gained a lot of attention, called the post selection. This concept can be viewed as a post selection based on the traditional standard measurement scheme. But today, this concept has already broken through the category of measurement and has become an important scheme for quantum state preparation and precision measurement. In this paper, we have done the application of dissipative control design in the photodynamic system. In a very meaningful way, two quantum devices with good performance are designed with cavity and tunneling induced transparency, and a pioneering study of the post selection problem of hot states is made. Through these studies, we can see the advantages of the dissipation control design and the subsequent selection of the weak measurement, especially the very unique quantum system preparation and control. The system has become a hot field in the field of experimental quantum optics and has also aroused many original theoretical studies. Since the mechanical oscillator system is a macro system, the quantum correlation it can produce is particularly important for us to understand all kinds of quantum basic problems. In this paper, we use the concept of dissipative control design to discuss the steady state entanglement of a four mode photomechanical system. Based on the idea of discussing the problem in the previous article, we used the idea of dissipative control design for the first time to use the light system at normal temperature. In the existing work, the two body of the photodynamic system. The logarithmic negativity of the entanglement is less than 0.7 at zero temperature and is not at all at normal temperature. The work of Wang Yingdan et al. Gives a method of strong entanglement for producing production, but their work is discussed at zero temperature. We find that the system can also get significant entanglement at normal temperature, which is very different from the previous work of photomechanical entanglement. It is also a typical case of quantum mechanics without the sub space. Then we use the same four mode photodynamic system to discuss the problem of coherent optical transfer at different wavelengths. The transfer information between different frequencies is a quantum network. In the existing scheme, in the existing scheme, if the quantum state transfer based on the photodynamic system is to obtain high conversion efficiency, the intensity of the driving light of the two target cavity modes is larger and the dissipation of the two cavity modes is almost equal. This is not conducive to the regulation and the excessive driving light will cause the heating of the mechanical vibrator. The conversion efficiency, on the other hand, is higher for the design of the two cavity. We first proposed the idea of the blue band edge driven dissipative control design. Although one control mode, the coupling intensity of coherent optical transfer can be greatly reduced, and the dissipation of the two target chambers can be very different. It is particularly important that I am here. We have revealed the idea of pattern elimination, which can be used in many other quantum control problems. The cavity can both increase and reduce the dissipation of quantum systems, and can greatly enhance the coupling intensity of light and quantum systems. And tunneling induced transparency is a common dissipative channel that makes two adjacent quantum modes. In this paper, we have designed two kinds of quantum devices using these two methods, all of which are in the middle infrared region, one can delay the time of light propagation, and the other can switch the light of two frequencies. These two designs have been applied for patent. It has been widely disputed, but its unique weak function of abnormal amplification has been recognized and widely studied. In the present work, the idea of using the weak measurement to put single photon nonlinearity in the Da's medium has been greatly developed recently. But in the present work, they only discuss the coherent light. In our work, in our work, we use a hot pointer to explore the single photon cross Kerr effect. We have made a very detailed discussion. We found that the amplification of the hot pointer and the coherent light pointer is very different, and the amplification effect of the hot state pointer is more significant. We extend the weak effect to the strong effect of the hot state pointer. We find that the traditional weak value interpretation is unfounded for strong effects. At the same time, we also give the reduction effect of the post selection and the magnification of the large probability. These conclusions are beyond the previous research. The thermal cross Kerr effect further reveals that the virtual amplification effect of the post selective weak amplification is a pure channel. Canonical effect, and combined with the recent balanced weak measurement technique, we give the general mechanism of virtual amplification.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O413

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