von Neumann entropy
- To: mathgroup at smc.vnet.net
- Subject: [mg43129] von Neumann entropy
- From: Chad Junkermeier <cej38 at email.byu.edu>
- Date: Wed, 13 Aug 2003 07:49:59 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Dear Mathgroup, I have been trying to use Mathematica to compute the von Neumann entropy of a density matrix and have run into trouble with telling Mathematica to use a particular definition in the calculation. The von Neumann entropy is defined as S = -Tr [ rho Ln (rho)], where rho is a square matrix. The problem is how to handle the case when and element of the matrix rho is zero. I want to tell Mathematica to assume that 0 * Ln(0) = 0 when it is computing the entropy. How do I tell it to make that assumption? Thanks, Chad