I recently took a great interest in topological quantum computing - so great an interest I am even considering it as a thesis topic for grad school (though I am still a junior undergrad and have awhile to figure that out). What would be some useful courses to take to pursue theoretical research in this field, besides the typical courses a physics undergrad would take (complex analysis, PDEs, numerical analysis, etc.). Would actually taking a topology class in the math department be useful, or would I take some topology-for-physics style class in grad school? Howabout modern algebra? Information theory? What about algebraic topology? As it stands, I may not be able to take topology before I graduate (it depends on what I end up doing this spring), but I would be able to take algebraic topology.