Negative Conditional Entropy of Post-Selected States

Abstract

We define a quantum entropy conditioned on post-selection which has the von Neumann entropy of pure states as a special case. This conditional entropy can take negative values which is consistent with part of a quantum system containing less information than the whole which can be in a pure state. The definition is based on generalised density operators for postselected ensembles. The corresponding density operators are consistent with the quantum generalisation of classical conditional probabilities following Dirac s formalism of quasiprobability distributions.

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Cited by in corpus (6)

• Holographic Pseudo Entropy
• Geometry of two-qubit states with negative conditional entropy
• Rényi entropies and negative central charges in non-Hermitian quantum systems
• SVD Entanglement Entropy
• Quantum logical entropy: fundamentals and general properties
• Topologically protected negative entanglement