Four classes of few-weight self-orthogonal codes and their applications for LCD codes and quantum codes
This work investigates the construction of self-orthogonal codes with relatively few non-zero weights and their applications to LCD and quantum code design. By introducing two new types of defining sets and leveraging augmented code techniques together with algebraic structures over finite fields, the authors systematically construct—for the first time—a family of projective four-weight and three families of general four-weight self-orthogonal codes, while precisely determining the parameters of their duals. Some of the resulting LCD codes have duals that nearly attain the sphere-packing bound, and the derived quantum codes achieve almost maximum distance separable (AMDS) performance, thereby demonstrating the superiority and practical relevance of the newly constructed code families.