Question: when solving system of DEs I get a null answer why?

I'm trying to solve:

sys:=[diff(A(t),t)=sigma^(1/2)*(sigma+1)*d*B(t)-sigma*A(t),diff(B(t),t)=I*A(t)-0.5*I*A(t)*omega(t)-B(t),diff(omega(t),t)=-I*A(t)*B(t)-nu*omega(t)];
          d              1/2
  sys := [-- A(t) = sigma    (sigma + 1) d B(t) - sigma A(t),
          dt

        d
        -- B(t) = A(t) I - 0.5 I A(t) omega(t) - B(t),
        dt

        d
        -- omega(t) = -A(t) B(t) I - nu omega(t)]
        dt

> IBC:=[D(A)(0)=1,D(B)(0)=0,D(omega)(0)=0];

          IBC := [D(A)(0) = 1, D(B)(0) = 0, D(omega)(0) = 0]

> d:=3;nu:=0.5;sigma=1;

                                d := 3


                              nu := 0.5


                              sigma = 1

> PDEsolve1:=dsolve([op(sys),op(IBC)]);

                            PDEsolve1 :=
 

as you can see I keep getting a null anwer unless I set all my Initial conditions equal to 0.

Please any suggestions.

Thanks

Siân