论文标题
与固定电荷的混合状态的经典相关性有效分离量子
Efficient separation of quantum from classical correlations for mixed states with a fixed charge
论文作者
论文摘要
纠缠是量子技术的关键资源，是令人兴奋的多体现象的根源。但是，量化现实世界量子系统的两个部分之间的纠缠在与环境相互作用时具有挑战性，因为后者将跨边界的经典与量子相关性混合在一起。在这里，我们使用混合状态的操作员空间纠缠频谱有效地量化了这种现实的开放系统中的量子相关性。如果系统具有固定电荷，我们表明光谱值的一个子集编码不同的跨边界配置之间的连贯性。这些值的总和我们称为“配置相干”，可以用作跨边界相干性的量词。至关重要的是，我们证明，对于纯度非刺激地图，例如，使用Hermitian跳跃操作员的Lindblad型演变，配置连贯性是纠缠的措施。此外，可以使用状态密度矩阵的张量网络表示有效地计算它。我们展示了在脱离存在下在链上移动的无旋转粒子的配置相干性。我们的方法可以在广泛的系统中量化连贯性和纠缠，并激发有效的纠缠检测。
Entanglement is the key resource for quantum technologies and is at the root of exciting many-body phenomena. However, quantifying the entanglement between two parts of a real-world quantum system is challenging when it interacts with its environment, as the latter mixes cross-boundary classical with quantum correlations. Here, we efficiently quantify quantum correlations in such realistic open systems using the operator space entanglement spectrum of a mixed state. If the system possesses a fixed charge, we show that a subset of the spectral values encode coherence between different cross-boundary charge configurations. The sum over these values, which we call "configuration coherence", can be used as a quantifier for cross-boundary coherence. Crucially, we prove that for purity non-increasing maps, e.g., Lindblad-type evolutions with Hermitian jump operators, the configuration coherence is an entanglement measure. Moreover, it can be efficiently computed using a tensor network representation of the state's density matrix. We showcase the configuration coherence for spinless particles moving on a chain in presence of dephasing. Our approach can quantify coherence and entanglement in a broad range of systems and motivates efficient entanglement detection.
