Suppose we want to benchmark a quantum device held by a remote party, e.g., by testing its ability to carry out challenging quantum measurements outside of a free set of measurements $\mathcal{M}$. A very simple way to do so is to set up a binary-state discrimination task that cannot be solved efficiently by means of free measurements. If we can find pairs of orthogonal states that become arbitrarily indistinguishable under measurements in $\mathcal{M}$, in the sense that the error probability in discrimination approaches that of a random guess, we say that there are data hiding against $\mathcal{M}$. Here we investigate data hiding in the context of continuous-variable quantum systems. First, we look at the case where $\mathcal{M}$ denotes the set of measurements implementable with local operations and classical communication. While previous studies have placed upper bounds on the maximum efficiency of data hiding in terms of the local dimension and are thus not applicable to continuous-variable systems, we establish more general bounds that rely solely on the local mean photon number of the states employed. Along the way, we perform a rigorous quantitative analysis of the error introduced by the nonideal Braunstein-Kimble quantum teleportation protocol, determining how much squeezing and local detection efficiency are needed in order to teleport an arbitrary multimode local state of known mean energy with a prescribed accuracy. Finally, following a seminal proposal by Sabapathy and Winter, we look at data hiding against Gaussian operations assisted by the feedforward of measurement outcomes, providing an example of a relatively simple scheme that works with a single mode only.

中文翻译：

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连续变量系统的量子数据隐藏

假设我们想要对远程方持有的量子设备进行基准测试，例如，通过测试其在一组免费测量之外执行具有挑战性的量子测量的能力 $\mathcal{米}$. 一个非常简单的方法是设置一个不能通过自由测量有效解决的二元状态判别任务。如果我们能找到在测量下变得任意不可区分的正交状态对$\mathcal{米}$，在歧视中的错误概率接近随机猜测的意义上，我们说有数据隐藏反对 $\mathcal{米}$. 在这里，我们研究了连续可变量子系统背景下的数据隐藏。首先，我们来看一个案例$\mathcal{米}$表示可通过本地操作和经典通信实现的一组测量。虽然之前的研究已经根据局部维度对数据隐藏的最大效率设置了上限，因此不适用于连续变量系统，但我们建立了更一般的界限，仅依赖于所采用状态的局部平均光子数。在此过程中，我们对非理想的 Braunstein-Kimble 量子隐形传态协议引入的误差进行了严格的定量分析，确定需要多少压缩和局部检测效率才能使用规定的平均能量传送已知平均能量的任意多模局部状态准确性。最后，根据 Sabapathy 和 Winter 的开创性建议，