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arXiv 2205.04872quant-phphysics.optics
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用于量子态工程的受控离散时间量子行走

Steered discrete-time quantum walks for engineering of quantum states

Gururaj Kadiri

AI总结:

该研究分析了受控离散时间量子行走在二分量子系统态生成中的局限,提出了行走可达态的生成与最短路构建算法,并在线性光学平台上验证了全态可达性及矢量光束实现方案。

摘要:

我们分析了受控离散时间量子行走在生成由量子比特耦合至qudit系统构成的二分量子系统量子态方面的优势与局限。我们证明,即使采用最广义的量子步定义,复合空间中并非所有量子态都能通过量子行走到达,这使得复合希尔伯特空间被划分为“行走可达态”与“行走不可达态”。我们提出了一种算法,可从易于实现的直积态出发,以最少的单位步长量子步生成任意行走可达态。我们进一步给出了在任意一对此类行走可达态之间构建最少量子行走的方案。线性光学是实现基于硬币的量子行走的常用物理系统,其复合空间由光束的自旋角动量与轨道角动量构建而成。我们证实,在该实现中,所有归一化量子态均为“行走可达态”。此外,任意广义量子步都可通过单个q-plate(q波片)和一对均匀波片实现,仅相差一个全局相位。我们随后提出了一种基于量子行走的方案,仅使用q-plate和波片即可实现任意矢量光束。

英文摘要:

We analyze the strengths and limitations of steered discrete time quantum walks in generating quantum states of bipartite quantum systems comprising of a qubit coupled to a qudit system. We demonstrate that not all quantum states in the composite space are accessible through quantum walks, even under the most generalized definition of a quantum step, leading to a bifurcation of the composite Hilbert space into "walk-accessible states" and the "walk-inaccessible states". We give an algorithm for generating any walk-accessible state from a simple-to-realize product state, in a minimal number of walk steps, all of unit step size. We further give a prescription towards constructing minimal quantum walks between any pair of such walk-accessible states. Linear optics has been a popular physical system for implementing coin-based quantum walks, where the composite space is built up of spin and orbital angular momenta of light beams. We establish that in such an implementation, all normalized quantum states are "walk-accessible". Furthermore, any generalized quantum step can be implemented upto a global phase using a single q-plate and a pair of homogeneous waveplates. We then give a quantum walk based scheme for realizing arbitrary vector beams, using only q-plates and waveplates.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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