Hi!

hi, I am searching for a software or library that can handle operator algebra in quantum mechanics. For example, I would like to caculate the commutator [a,H], where the Hamiltonian "H"=\epsilon a^{\dag}a, and "a" is annihilation operator for, say, an osilator. I tried GiNaC, and read much documentation, and get little clue. I wonder if there is a direct implementation of these kind of operator algebra in GiNaC.

You can declare those operators as noncommutative symbols. I assume that you are using version 1.3.x. Then it goes as e.g., const unsigned my_tinfo = 2; symbol a("a", return_types::noncommutative, my_tinfo); symbol adag("adag", return_types::noncommutative, my_tinfo); H = epsilon*adag*a; ex commu = a*H - H*a commu = rewrite_operators(commu); The global constant my_tinfo is arbitrary, but for safety it should not be one that is already in use (see http://www.ginac.de/viewcvs/GiNaC/ginac/tinfos.h?hideattic=0&rev=1.27.2.3&view=markup). You would have to define the function rewrite_operators yourself. It could be something like ex rewrite_operators(const ex &x) { if (is_a<ncmul>(x)) { ... constructing the result of rewriting is done here ... return result; } else return x.map(rewrite_operators); } Good luck! Chris