Breaking absolute separability with quantum switch

Fuente: arXiv
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Hauptverfasser: Yanamandra, Sravani, Srinidhi, P V, Bhattacharya, Samyadeb, Chakrabarty, Indranil, Goswami, Suchetana
Format: Preprint
Veröffentlicht: 2023
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author Yanamandra, Sravani
Srinidhi, P V
Bhattacharya, Samyadeb
Chakrabarty, Indranil
Goswami, Suchetana
author_facet Yanamandra, Sravani
Srinidhi, P V
Bhattacharya, Samyadeb
Chakrabarty, Indranil
Goswami, Suchetana
contents Absolute separable (AS) quantum states are those states from which it is impossible to create entanglement, even under global unitary operations. It is known from the resource theory of non-absolute separability that the set of absolute separable states forms a convex and compact set, and global unitaries are free operations. We show that the action of a quantum switch controlled by an ancilla qubit over the global unitaries can break this robustness of AS states and produce ordinary separable states. First, we consider bipartite qubit systems and find the effect of quantum switch starting from the states sitting on the boundary of the set of absolute separable states. As particular examples, we illustrate what happens to modified Werner states and Bell diagonal (BD) states. For the Bell diagonal states, we provide the structure for the set of AS BD states and show how the structure changes under the influence of a switch. Further, we consider numerical generalisation of the global unitary operations and show that it is always possible to take AS states out of the convex set under switching operations. We also generalised our results in higher dimensions.
format Preprint
id arxiv_https___arxiv_org_abs_2310_04819
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Breaking absolute separability with quantum switch
Yanamandra, Sravani
Srinidhi, P V
Bhattacharya, Samyadeb
Chakrabarty, Indranil
Goswami, Suchetana
Quantum Physics
Absolute separable (AS) quantum states are those states from which it is impossible to create entanglement, even under global unitary operations. It is known from the resource theory of non-absolute separability that the set of absolute separable states forms a convex and compact set, and global unitaries are free operations. We show that the action of a quantum switch controlled by an ancilla qubit over the global unitaries can break this robustness of AS states and produce ordinary separable states. First, we consider bipartite qubit systems and find the effect of quantum switch starting from the states sitting on the boundary of the set of absolute separable states. As particular examples, we illustrate what happens to modified Werner states and Bell diagonal (BD) states. For the Bell diagonal states, we provide the structure for the set of AS BD states and show how the structure changes under the influence of a switch. Further, we consider numerical generalisation of the global unitary operations and show that it is always possible to take AS states out of the convex set under switching operations. We also generalised our results in higher dimensions.
title Breaking absolute separability with quantum switch
topic Quantum Physics
url https://arxiv.org/abs/2310.04819