Physics 4999E Final: 09

• School: Western University
• Department: Physics
• Course: Physics 4999E
• Professor: john stockholm

Document Summary

Cs 766/qic 820 theory of quantum information (fall 2011) For the next several lectures we will be discussing the von neumann entropy and various con- cepts relating to it. This lecture is intended to introduce the notion of entropy and its connection to compression. Before we discuss the von neumann entropy, we will take a few moments to discuss the shannon entropy. This is a purely classical notion, but it is appropriate to start here. The shannon entropy of a probability vector p r is de ned as follows: Here, and always in this course, the base of the logarithm is 2. (we will write ln( ) if we wish to refer to the natural logarithm of a real number . ) It is typical to express the shannon entropy slightly more concisely as which is meaningful if we make the interpretation 0 log(0) = 0.