On two maximally entangled couples

• URL: http://arxiv.org/abs/2506.21282v1
• Date: Thu, 26 Jun 2025 14:03:59 GMT
• Title: On two maximally entangled couples
• Abstract summary: In a seminal article, Higuchi and Sudbery showed that a pure four-qubit state can not be maximally entangled across every bi partition.<n>Such states are now known as absolutely maximally entangled (AME) states.<n>Here we give a series of old and new proofs of the fact that no four-qubit AME state exists.
• Score: 3.069335774032178
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: In a seminal article, Higuchi and Sudbery showed that a pure four-qubit state can not be maximally entangled across every bipartition. Such states are now known as absolutely maximally entangled (AME) states. Here we give a series of old and new proofs of the fact that no four-qubit AME state exists. These are based on invariant theory, methods from coding theory, and basic properties from linear algebra such as the Pauli commutation relations.

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