  We consider a one-dimensional chain of N equidistantly spaced noninteracting
qubits embedded in an open waveguide. In the frame of single-excitation
subspace, we systematically study the evolution of qubits amplitudes if the
only qubit in the chain was initially excited. We show that the temporal
dynamics of qubits amplitudes crucially depend on the value of kd, where k is
the wave vector, d is a distance between neighbor qubits. If kd is equal to an
integer multiple of $\pi$, then the qubits are excited to a stationary level
which scales as SN^{-1}S. We show that in this case, it is the dark states
which prevent qubits from decaying to zero even though they do not contribute
to the output spectrum of photon emission. For other values of kd the
excitations of qubits have the form of damping oscillations, which represent
the vacuum Rabi oscillations in a multi-qubit system. In this case, the output
spectrum of photon radiation is defined by a subradiant state with the smallest
width.
