Quantum Error Correction Codes and Their Impact on Scalable Quantum Computation: Current Approaches and Future Perspectives Mehmet Keçeci ORCID : https://orcid.org/0000-0001-9937-9839, İstanbul, Türkiye Received: 24.05.2025 “Article 3 of the series” Abstract: Quantum computers hold the potential to solve complex problems intractable for classical supercomputers. However, the inherent susceptibility of quantum systems to decoherence and environmental noise poses the most significant barrier to realizing this potential. Quantum Error Correction (QEC) codes (Quantum Error Correction (QEC) Codes [Unpublished pre-doctoral III. technical reports]. Gebze Technical University, Kocaeli, Türkiye [319, 461, 481, 482]) aim to preserve the integrity of quantum information by actively detecting and correcting these noisy effects, thereby enabling fault-tolerant, scalable quantum computation. This paper begins with the fundamental concepts in QEC, discussing early seminal approaches such as stabilizer codes, notably the Shor and Steane codes. It then focuses on topological error correction codes, which are currently an intensive area of research, particularly surface codes and color codes. The advantages of these codes, such as high error thresholds and local interaction requirements, are discussed alongside their drawbacks, including physical qubit overhead and challenges in implementing logical gates. The paper also examines alternative approaches like Low-Density Parity-Check (LDPC) codes and their potential benefits. Fundamental challenges in implementing QEC, the practical implications of the threshold theorem, the importance of noise modelling (including non-Markovian and correlated errors), and the role of characterization techniques like quantum process tomography and randomized benchmarking are highlighted. Finally, current research trends such as dynamic encoding, error suppression, and hardware-software co-design are evaluated, along with potential future directions and open problems for QEC strategies. This work aims to underscore the central role of QEC in the future of quantum computing and the importance of continuous progress in this field. Keywords: Quantum Error Correction, QEC, Decoherence, Stabilizer Codes, Topological Codes, Surface Code, Fault-Tolerant Quantum Computation, Threshold Theorem, Quantum Noise. Note: Citations and numbering are in continuation of the previous article.