Entanglement, correlations and data-structure in many-body quantum systems

Paola Ruggiero

Faluke Aikebaier, Teemu Ojanen, José Luis Lado

A quantum coherent screening cloud around a magnetic impurity in metallic systems is the hallmark of the antiferromagnetic Kondo effect. Despite the central role of the Kondo effect in quantum materials, the structure of quantum correlations of the screening cloud has defied direct observations. In this work, we introduce a machine-learning algorithm that allows one to spatially map the entangled electronic modes in the vicinity of the impurity site from experimentally accessible data. We demonstrate that local correlators allow reconstruction of the local many-body correlation entropy in real space in a double Kondo system with overlapping entanglement clouds. Our machine-learning methodology allows bypassing the typical requirement of measuring long-range nonlocal correlators with conventional methods. We show that our machine-learning algorithm is transferable between different Kondo system sizes, and we show its robustness in the presence of noisy correlators. Our work establishes the potential machine-learning methods to map many-body entanglement from real-space measurements.

Paul Cooney

Paper VI — Entanglement Information Locality and Many-Body Structure DescriptionThis work extends ordered-dynamics locality principles to composite systems, deriving entanglement structure and many-body correlations from operational constraints. Entanglement emerges as a necessary feature of jointly constrained information propagation, not as an added axiom. The paper clarifies the operational meaning of non-separability and establishes the foundations for multi-particle quantum structure within the ODRP. Keywordsentanglement; many-body systems; quantum correlations; operational locality; information theory; quantum foundations

Frank Verstraete

T.Y. Zhang, Wentao Ji, Yuhang Guo +6 more

Understanding the nonequilibrium dynamics of isolated quantum many-body systems is a central goal of modern physics. Measuring genuine many-body correlations in quantum systems is central to this aim, while it remains a fundamental challenge for systems lacking individual addressability. We introduce a multidimensional correlation imprinting technique that encodes the structure of a many-body state into the temporal fluctuation spectrum of a local quantum probe. This allows direct measurement of arbitrary-order correlations in nonequilibrium quantum states. Using a nitrogen-vacancy center in diamond coupled to a ^{13}C nuclear spin bath, we experimentally reconstruct many-body correlation landscape to third order. Furthermore, by analyzing the spectral structure of correlation cumulants, we directly visualize the dynamics of quantum entanglement. Our Letter establishes a general approach to probing complex nonequilibrium phenomena and entanglement in quantum many-body systems at the nanoscale.

J. W. Clark, Hessam Habibian, Aikaterini Mandilara +1 more