Identifying families of multipartite states with non-trivial local entanglement transformations

The study of state transformations by spatially separated parties with local operations assisted by classical communication (LOCC) plays a crucial role in entanglement theory and its applications in quantum information processing. Transformations of this type among pure bipartite states were charact...

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Main Authors: Nicky Kai Hong Li, Cornelia Spee, Martin Hebenstreit, Julio I. de Vicente, Barbara Kraus
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2024-02-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2024-02-29-1270/pdf/
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author Nicky Kai Hong Li
Cornelia Spee
Martin Hebenstreit
Julio I. de Vicente
Barbara Kraus
author_facet Nicky Kai Hong Li
Cornelia Spee
Martin Hebenstreit
Julio I. de Vicente
Barbara Kraus
author_sort Nicky Kai Hong Li
collection DOAJ
description The study of state transformations by spatially separated parties with local operations assisted by classical communication (LOCC) plays a crucial role in entanglement theory and its applications in quantum information processing. Transformations of this type among pure bipartite states were characterized long ago and have a revealing theoretical structure. However, it turns out that generic fully entangled pure multipartite states cannot be obtained from nor transformed to any inequivalent fully entangled state under LOCC. States with this property are referred to as isolated. Nevertheless, multipartite states are classified into families, the so-called SLOCC classes, which possess very different properties. Thus, the above result does not forbid the existence of particular SLOCC classes that are free of isolation, and therefore, display a rich structure regarding LOCC convertibility. In fact, it is known that the celebrated $n$-qubit GHZ and W states give particular examples of such classes and in this work, we investigate this question in general. One of our main results is to show that the SLOCC class of the 3-qutrit totally antisymmetric state is isolation-free as well. Actually, all states in this class can be converted to inequivalent states by LOCC protocols with just one round of classical communication (as in the GHZ and W cases). Thus, we consider next whether there are other classes with this property and we find a large set of negative answers. Indeed, we prove weak isolation (i.e., states that cannot be obtained with finite-round LOCC nor transformed by one-round LOCC) for very general classes, including all SLOCC families with compact stabilizers and many with non-compact stabilizers, such as the classes corresponding to the $n$-qunit totally antisymmetric states for $n\geq4$. Finally, given the pleasant feature found in the family corresponding to the 3-qutrit totally antisymmetric state, we explore in more detail the structure induced by LOCC and the entanglement properties within this class.
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spelling doaj.art-8fe48a4c789942d88c7b035bb9e238732024-02-29T14:40:16ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2024-02-018127010.22331/q-2024-02-29-127010.22331/q-2024-02-29-1270Identifying families of multipartite states with non-trivial local entanglement transformationsNicky Kai Hong LiCornelia SpeeMartin HebenstreitJulio I. de VicenteBarbara KrausThe study of state transformations by spatially separated parties with local operations assisted by classical communication (LOCC) plays a crucial role in entanglement theory and its applications in quantum information processing. Transformations of this type among pure bipartite states were characterized long ago and have a revealing theoretical structure. However, it turns out that generic fully entangled pure multipartite states cannot be obtained from nor transformed to any inequivalent fully entangled state under LOCC. States with this property are referred to as isolated. Nevertheless, multipartite states are classified into families, the so-called SLOCC classes, which possess very different properties. Thus, the above result does not forbid the existence of particular SLOCC classes that are free of isolation, and therefore, display a rich structure regarding LOCC convertibility. In fact, it is known that the celebrated $n$-qubit GHZ and W states give particular examples of such classes and in this work, we investigate this question in general. One of our main results is to show that the SLOCC class of the 3-qutrit totally antisymmetric state is isolation-free as well. Actually, all states in this class can be converted to inequivalent states by LOCC protocols with just one round of classical communication (as in the GHZ and W cases). Thus, we consider next whether there are other classes with this property and we find a large set of negative answers. Indeed, we prove weak isolation (i.e., states that cannot be obtained with finite-round LOCC nor transformed by one-round LOCC) for very general classes, including all SLOCC families with compact stabilizers and many with non-compact stabilizers, such as the classes corresponding to the $n$-qunit totally antisymmetric states for $n\geq4$. Finally, given the pleasant feature found in the family corresponding to the 3-qutrit totally antisymmetric state, we explore in more detail the structure induced by LOCC and the entanglement properties within this class.https://quantum-journal.org/papers/q-2024-02-29-1270/pdf/
spellingShingle Nicky Kai Hong Li
Cornelia Spee
Martin Hebenstreit
Julio I. de Vicente
Barbara Kraus
Identifying families of multipartite states with non-trivial local entanglement transformations
Quantum
title Identifying families of multipartite states with non-trivial local entanglement transformations
title_full Identifying families of multipartite states with non-trivial local entanglement transformations
title_fullStr Identifying families of multipartite states with non-trivial local entanglement transformations
title_full_unstemmed Identifying families of multipartite states with non-trivial local entanglement transformations
title_short Identifying families of multipartite states with non-trivial local entanglement transformations
title_sort identifying families of multipartite states with non trivial local entanglement transformations
url https://quantum-journal.org/papers/q-2024-02-29-1270/pdf/
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