论文标题
从部分信息中界定量子多体状态的忠诚度
Bounding the fidelity of quantum many-body states from partial information
论文作者
论文摘要
我们制定了一种算法，以降低量子多体状态之间的忠诚度，例如偏部分信息，例如，少数体现可观察到的量子。我们的方法尤其是针对置换状态的量身定制的，但是在这种对称性甚至部分的情况下，它在所有情况下都产生了非平凡的结果。该属性使其对于可以从集体测量中认证相关多体状态的原子集合实验特别有用。例如，我们表明，$ n = 100 $粒子的$ξ^2 \ of-6 \; \ text {db} $ spin挤压状态只能通过$ f = 0.999 $的忠诚度证明，仅从其极化和挤压的Quadratoration的测量中。此外，我们展示了如何定量地说明州的测量噪声和部分对称性，这使我们的方法在现实的实验情况下有用。
We formulate an algorithm to lower bound the fidelity between quantum many-body states only from partial information, such as the one accessible by few-body observables. Our method is especially tailored to permutationally invariant states, but it gives nontrivial results in all situations where this symmetry is even partial. This property makes it particularly useful for experiments with atomic ensembles, where relevant many-body states can be certified from collective measurements. As an example, we show that a $ξ^2\approx-6\;\text{dB}$ spin squeezed state of $N=100$ particles can be certified with a fidelity up to $F=0.999$, only from the measurement of its polarization and of its squeezed quadrature. Moreover, we show how to quantitatively account for both measurement noise and partial symmetry in the states, which makes our method useful in realistic experimental situations.
