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arXiv · 2307.11478

No-go theorems for photon state transformations in quantum linear optics

Pablo V. Parellada·Vicent Gimeno i Garcia·Julio-José Moyano-Fernández·Juan Carlos Garcia-Escartin
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Abstract

We give a necessary condition for photon state transformations in linear optical setups preserving the total number of photons. From an analysis of the algebra describing the quantum evolution, we find a conserved quantity that appears in all allowed optical transformations. We comment some examples and numerical applications, with example code, and give three general no-go results. These include (i) the impossibility of deterministic transformations which redistribute the photons from one to two different modes, (ii) a proof that it is impossible to generate a perfect Bell state in heralded schemes with a separable input for any number of ancillary photons and modes and a fixed herald and (iii) a restriction for the conversion between different types of entanglement (converting GHZ to W states).

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Pablo V. Parellada, Vicent Gimeno i Garcia, Julio-José Moyano-Fernández, Juan Carlos Garcia-Escartin. 2023-07-21. No-go theorems for photon state transformations in quantum linear optics. https://doi.org/10.1016/j.rinp.2023.107108

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