Superadditivity of quantum channel capacity

Fatih Ozaydin, Sahin Kaya Ozdemir, Masato Koashi, Nobuyuki Imoto

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Superadditivity of quantum capacity of communication channels is one of the most interesting findings of the field. Yard and Smith, finding a relation between the private capacity and the assisted quantum capacity, showed a striking example of superadditivity, i.e. two channels of zero quantum capacity could achieve a positive quantum capacity when used together [1]. The four dimensional channels they used are a 50% erasure channel (therefore zero quantum capacity, due to no-cloning theorem) and a Horodecki channel (again zero quantum capacity due to incapability of sharing free entanglement). In this work we present the more general cases of superadditivity. Directly calculating the lower bounds of joint quantum capacities without using the relation between private capacity and assisted quantum capacity, we examine scenarios considering erasure channels of arbitrary probabilities and different Horodecki channels, and discuss the roles of degradability and anti-degradability as well as the role of the private capacity in superadditivity. We also derive an upper bound for the joint quantum capacity for the superactivation case.

Original languageEnglish (US)
Title of host publication2nd International Advances in Applied Physics and Materials Science Congress
Number of pages5
StatePublished - 2012
Event2nd International Advances in Applied Physics and Materials Science Congress, APMAS 2012 - Antalya, Turkey
Duration: Apr 26 2012Apr 29 2012

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other2nd International Advances in Applied Physics and Materials Science Congress, APMAS 2012

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


Dive into the research topics of 'Superadditivity of quantum channel capacity'. Together they form a unique fingerprint.

Cite this