In this paper, a controlled-phase (CPHASE) gate using the polarisation and orbital angular momentum degrees of freedom for single-photon two-qubit quantum logic is proposed. This is critical to the realisation of quantum cluster states and graph networks using transverse degrees of freedom. A generalisation of the proposed scheme to arbitrary number and kinds of degrees of freedom, for optical systems, as well as arbitrary operations to be conditionally performed is proposed.

中文翻译：

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具有极化和轨道角动量自由度并推广到任意超条件门的量子超CPHASE门

本文提出了一种利用极化和轨道角动量自由度的单光子二量子位逻辑控制相控（CPHASE）门。这对于使用横向自由度实现量子簇状态和图网络至关重要。提出将所提出的方案推广到光学系统的任意数量和种类的自由度，以及有条件地执行的任意操作。