The solution can be found here:

http://math.tntech.edu/rafal/cliff11/index.html

oh you're right. i got the same error. i am using maple 11.

using aD an bD and so on was my 2nd idea ;-)

i have no idea what's wrong with this package. have you ever tried to use AntiCommutators? This realy sucks... I can't see any useness in this package. Always the same problem: no simplification of the operators...

let "b" be the creation and "a" the annihilation.

then:

##############

restart

with(Physics):

Setup(quantumop={a,b},algebrarule={%Commutator(a[i],b[j])=KroneckerDelta[i,j],%Commutator(a[i],a[j]=0,%Commutator(b[i],b[j])=0})

Commutator(b[i]a[i],b[i]

##############

and you get the answer b[i]

Im am also facing this problem. Seems to be a bug.

Why don't you try

Setup(quantumop={a,b,c}, algebrarule={%Commutator(Dagger(a), c)=0, %Commutator(a, c)=0,%Commutator(Dagger(b), c)=0, %Commutator(b, c)=0})