  Quantum stabilizer codes (QSCs) suffer from a low quantum coding rate, since
they have to recover the quantum bits (qubits) in the face of both bit-flip and
phase-flip errors. In this treatise, we conceive a low-complexity concatenated
quantum turbo code (QTC) design exhibiting a high quantum coding rate. The high
quantum coding rate is achieved by combining the quantum-domain version of
short-block codes (SBCs) also known as single parity check (SPC) codes as the
outer codes and quantum unity-rate codes (QURCs) as the inner codes. Despite
its design simplicity, the proposed QTC yields a near-hashing-bound error
correction performance. For instance, compared to the best half-rate QTC known
in the literature, namely the QIrCC-QURC scheme, which operates at the distance
of $D = 0.037$ from the quantum hashing bound, our novel QSBC-QURC scheme can
operate at the distance of $D = 0.029$. It is worth also mentioning that this
is the first instantiation of QTCs capable of adjusting the quantum encoders
according to the quantum coding rate required for mitigating the Pauli errors
given the different depolarizing probabilities of the quantum channel.
