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Register a new userQuantum data hiding with continuous variable systems
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Ludovico Lami
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In an abstract sense, quantum data hiding is the manifestation of the fact that two classes of quantum measurements can perform very differently in the task of binary quantum state discrimination. We investigate this phenomenon in the context of continuous variable quantum systems. First, we look at the celebrated case of data hiding against the set of local operations and classical communication. While previous studies have placed upper bounds on its maximum efficiency in terms of the local dimension and are thus not applicable to continuous variable systems, we tackle this latter case by establishing more general bounds that rely solely on the local mean photon number of the states employed. Along the way, we perform a quantitative analysis of the error introduced by the non-ideal Braunstein--Kimble quantum teleportation protocol, determining how much two-mode squeezing and local detection efficiency is needed in order to teleport an arbitrary local state of known mean energy with a prescribed accuracy. Finally, following a seminal proposal by Winter, we look at data hiding against the set of Gaussian operations and classical computation, providing the first example of a relatively simple scheme that works with a single mode only. The states employed can be generated from a two-mode squeezed vacuum by local photon counting; the larger the squeezing, the higher the efficiency of the scheme.
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