Spatially multimode squeezed light for quantum imaging and one-way quantum computing

用于量子成像和单向量子计算的空间多模压缩光

基本信息

批准号：
EP/I001743/1
负责人：
Vincent Boyer
金额：
$ 8.09万
依托单位：
University of Birmingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FI001743%2F1
关键词：
Spatially multimode squeezed light quantum

项目摘要

When recorded with sensitive detectors, the electric field of the light reveals unavoidable quantum fluctuations in its phase and amplitude. It is a manifestation of the Heisenberg uncertainty principle. While it is impossible to create a light field with simultaneously known phase and amplitude, it is possible to reduce the quantum noise of either the phase or the amplitude in exchange of increased quantum noise on the other variable. This phenomenon is known as squeezing.Up till now, strongly squeezed light has only been produced in one single optical mode at a time (typically a Gaussian beam). This means that the fluctuations of the beam are squeezed when the field is considered in its full spatial extent but that measuring only a portion of the cross-section of the beam will yield little squeezing. For instance, an amplitude-squeezed beam will have reduced fluctuations in its total power, but its intensity profile will still present some roughness (local fluctuations). This proposal aims to produce light fields that are squeezed in amplitude at any point of their transverse profile. As a consequence, the intensity profile should be smooth, even at the quantum level. From a different point of view, the beam is squeezed in multiple transverse optical modes, hence the name multi-spatial-mode (MSM) squeezed light .The starting point will be four-wave mixing in an atomic vapour, a non-linear process in which the medium, when pumped by an intense laser beam, converts a pair of incoming photons into two photons with correlated positions and directions. The output of the four-wave mixing process contains strong correlations at the photon level and can be further transformed through simple linear optics into a MSM squeezed beam of light, where the photons are regularly distributed inside the beam.We will apply this non-classical state of light to two experiment which epitomise two aspects of modern quantum optics: quantum measurements and quantum information processing.First, we will show that MSM squeezed light can improve the quantum limit on optical resolution. In a microscopy set-up, MSM squeezed illumination of the observed object allows for the formation of a smoother image, with reduced spatial quantum noise. Using known techniques of super-resolution, it is then possible to reconstruct the objects in greater details than what would be possible with classical illumination.Second, we will demonstrate the potential of MSM squeezed light to produce quantum states of light that are relevant to a class of quantum computing. These states, called cluster states, are made of a collection of entangled modes and can be built from an ensemble of squeezed beams with a network of beam-splitters. Since MSM squeezed light corresponds to a collection of squeezed optical modes, it actually constitutes the proper resource for the creation of a cluster state. As a demonstration, we will seek to produce a small cluster state.

当用灵敏探测器记录时，光的电场揭示了其相位和振幅中不可避免的量子涨落。它是海森堡测不准原理的体现。虽然不可能创建一个同时已知相位和振幅的光场，但可以减少相位或振幅的量子噪声，以换取另一个变量上增加的量子噪声。这种现象称为挤压。到目前为止，一次只能以一种单一光学模式（通常是高斯光束）产生强烈挤压的光。这意味着，当在整个空间范围内考虑场时，光束的波动会受到挤压，但仅测量光束横截面的一部分将产生很小的挤压。例如，振幅压缩光束的总功率波动会减少，但其强度分布仍会呈现一些粗糙度（局部波动）。该提案的目的是产生在其横向轮廓的任何点处幅度被压缩的光场。因此，即使在量子水平上，强度分布也应该是平滑的。从不同的角度来看，光束被压缩为多个横向光学模式，因此被称为多空间模式（MSM）压缩光。起点将是原子蒸气中的四波混合，这是一个非线性过程其中，当介质被强激光束泵浦时，会将一对入射光子转换为具有相关位置和方向的两个光子。四波混合过程的输出在光子水平上包含强相关性，可以通过简单的线性光学进一步转换为 MSM 压缩光束，其中光子规则分布在光束内。我们将应用这种非经典两个实验集中体现了现代量子光学的两个方面：量子测量和量子信息处理。首先，我们将证明MSM压缩光可以提高光学分辨率的量子极限。在显微镜设置中，MSM 压缩观察物体的照明，可以形成更平滑的图像，同时减少空间量子噪声。使用已知的超分辨率技术，可以比经典照明更详细地重建物体。其次，我们将演示 MSM 压缩光产生与光相关的量子态的潜力。量子计算类。这些状态称为簇状态，由纠缠模式的集合组成，可以通过具有分束器网络的压缩光束集合来构建。由于 MSM 压缩光对应于压缩光学模式的集合，因此它实际上构成了用于创建簇状态的适当资源。作为演示，我们将寻求产生一个小型集群状态。