Quantum Information Processing

, Volume 12, Issue 12, pp 3717–3723 | Cite as

Equivalence of classicality and separability based on P phase–space representation of symmetric multiqubit states

  • A. R. Usha Devi
  • A. K. Rajagopal
  • Sudha
  • H. S. Karthik
  • J. Prabhu Tej


Classical and quantum world views differ in peculiar ways. Understanding decisive quantum features—for which no classical explanation exist—and their interrelations is of foundational interest. Moreover, recognizing non-classical features carries practical significance in information processing tasks as it offers insights as to why quantum protocols work better than their classical counterparts. We focus here on two celebrated notions of non-classicality viz., negativity of P phase–space representation and entanglement in symmetric multiqubit systems. We prove that they imply each other.


Non-classicality Separability Quantum entanglement Phase space representation Symmetric multiqubit states 


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • A. R. Usha Devi
    • 1
    • 2
  • A. K. Rajagopal
    • 2
    • 3
  • Sudha
    • 2
    • 4
  • H. S. Karthik
    • 5
  • J. Prabhu Tej
    • 1
  1. 1.Department of PhysicsBangalore UniversityBangaloreIndia
  2. 2.Inspire Institute Inc.AlexandriaUSA
  3. 3.Harish-Chandra Research InstituteJhunsi, AllahabadIndia
  4. 4.Department of PhysicsKuvempu UniversityShimogaIndia
  5. 5.Raman Research InstituteBangaloreIndia

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