Entanglement of Assistance

  • David P. DiVincenzo
  • Christopher A. Fuchs
  • Hideo Mabuchi
  • John A. Smolin
  • Ashish Thapliyal
  • Armin Uhlmann
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1509)


The newfound importance of “ entanglement as a resource„ in quantum computation and quantum communication behooves us to quantify it in as many distinct ways as possible. Here we explore a new quantification of entanglement of a general (mixed) quantum state for a bipartite system, which we name entanglement of assistance. Weshowit to be the maximum of the average entanglement over all ensembles consistent with the density matrix describing the bipartite state. With the help of lower and upper bounds we calculate entanglement of assistance for a few cases and use these results to show the surprising property of superadditivity. We believe that this may throw some light on the question of additivity of entanglement of formation.


Density Matrix Pure State Bipartite System Forthcomming Publication Bipartite State 
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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • David P. DiVincenzo
    • 1
  • Christopher A. Fuchs
    • 2
  • Hideo Mabuchi
    • 2
  • John A. Smolin
    • 1
  • Ashish Thapliyal
    • 3
  • Armin Uhlmann
    • 4
  1. 1.IBM Research DivisionYorktown HeightsUSA
  2. 2.Bridge Laboratory of Physics 12-33California Institute of TechnologyPasadenaUSA
  3. 3.Department of PhysicsUniversity of California at Santa BarbaraSanta BarbaraUSA
  4. 4.Institut für Theoretische PhysikUniversität LeipzigLeipzigGermany

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