Hiding quantum data
David P. DiVincenzo, Patrick Hayden, et al.
Foundations of Physics
We introduce the notion of a Schmidt number of a bipartite density matrix. We show that k-positive maps witness the Schmidt number, in the same way that positive maps witness entanglement. We determine the Schmidt number of the family of states that is made from mixing the completely mixed state and a maximally entangled state. We show that the Schmidt number does not necessarily increase when taking tensor copies of a density matrix ρ; we give an example of a density matrix for which the Schmidt numbers of ρ and ρ⊗ρ are both 2.
David P. DiVincenzo, Patrick Hayden, et al.
Foundations of Physics
David P. DiVincenzo, John A. Smolin, et al.
New Journal of Physics
Barbara M. Terhal
Physics Letters, Section A: General, Atomic and Solid State Physics
Stefano Chesi, Daniel Loss, et al.
New Journal of Physics