Macroscopic Singlet, Triplet, and Colour-Charged States of Coherent Photons
Macroscopic Singlet, Triplet, and Colour-Charged States of Coherent Photons
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发表时间：
2023-03
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通讯作者：
S. Saito
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作者：
S. Saito
从激光源发射的光子射线处于相干态，其中宏观数量的光子在相同的量子态下简并。相干态具有自旋和轨道角动量的自由度，允许正交态之间任意叠加态，其幅度和相位不同，由李代数和李群的表示理论描述。在这里，我们通过实验证明，只需结合广泛使用的光学元件（例如半波片和四分之一波片以及涡旋透镜），我们就可以构建相干光子量子态的旋转发生器。我们发现涡旋态和非涡旋态之间的叠加态的特征是拓扑电荷在 SU(3) 态中旋转时的运动。我们还通过将光子射线与正交偏振态和涡旋态相结合来实现单重态和三重态。这对应于实现有效的 SU(4) 状态，并且我们已经确认在通过偏振器时投影到 SU(2)$\times$SU(2) 状态。
A ray of photons, emitted from a laser source, is in a coherent state, where macroscopic number of photons are degenerate in the same quantum state. The coherent state has degrees of freedom for spin and orbital angular momentum, which allow an arbitrary superposition state among orthogonal states with varying their amplitudes and phases, described by a representation theory of Lie algebra and Lie group. Here, we experimentally demonstrate that we can construct generators of rotations for the quantum states of coherent photons, simply by combining widely available optical components, such as half- and quarter-wave plates and vortex lenses. We have found that a superposition state between vortexed and no-vortex states is characterised by the motion of the topological charge upon the rotation in the SU(3) states. We also realised singlet and triplet states by combining rays of photons with orthogonal polarisation states and vortexed states. This corresponds to realise an effective SU(4) state and we have confirmed the projection to an SU(2)$\times$SU(2) state upon passing through a polariser.