Quantum Entropy and Its Connection to Superdense Coding and Quantum Cryptography

[iorfus]

Quantum entropy and ...??

Homework Statement

My problem is that I have to write about ten pages about SUPERDENSE CODING and QUANTUM CRYPTOGRAPHY, and my professor has taken for granted that these are strongly linked to quantum entropy. He never told us why! Indeed he talked about that as applications of the property quantum entropy. However, on the two books I am using (Nielsen&Chuang and Preskill's Lectures at CalTech), these two subjects are treated with no link to entropy.
Could someone please tell me where is the link? And when can I found material to get a reasonable understanding of that?
Thank you very much!

Homework Equations

The Attempt at a Solution

I have studied the properties of entropy and what there is on my books on superdense coding and quantum cryptography, but I can't find any link.

 

[lightgrav]

coding and cryptography are both mathematical abstractions, which are clearly well-connected to each other.
Write about these, and how they are related to one another, which (I understand) is the assignment.

Entropy is physical. Entropy was not mentioned (I understand) in the assignment.
Write what you know and think, maintaining your integrity - do not write what you think someone else wants you to write.

 

[Oxvillian]

Try googling "Shannon entropy".