Here are a few original ideas for a "bite-size" master's thesis topic within the realm of quantum decoherence and/or quantum measurement:
Investigating Decoherence in a Specific Quantum System: Choose a specific quantum system, such as a qubit or an ensemble of qubits, and explore the factors contributing to decoherence within that system. You could analyze the effects of different noise sources, such as environmental interactions, and propose mitigation strategies to minimize decoherence and improve the system's coherence time.
Quantum Measurement Schemes for Enhancing Coherence: Explore novel measurement schemes that can improve coherence in quantum systems. Investigate measurement techniques that have the potential to reduce measurement-induced backaction and minimize disturbance to the quantum state during measurement processes. This could involve studying weak measurements, continuous measurement strategies, or measurement backaction compensation techniques.
Quantum Error Correction and Decoherence: Focus on quantum error correction codes and their effectiveness in mitigating the impact of decoherence. Investigate specific error correction codes, their thresholds, and their performance under different decoherence models. Analyze the interplay between error correction codes and different noise sources, and propose improvements or novel approaches to enhance error correction capabilities.
Quantum Non-Demolition Measurements: Explore quantum non-demolition (QND) measurements and their applications in preserving quantum coherence. Investigate different QND measurement techniques, their theoretical foundations, and experimental implementations. Analyze the potential of QND measurements for high-precision measurements, quantum state monitoring, or protecting quantum information from decoherence.
Quantum Measurement and Quantum Information: Investigate the relationship between quantum measurement and quantum information theory. Explore how measurement processes affect quantum entanglement, quantum correlations, or quantum state distinguishability. Analyze the fundamental limits of measurement precision in terms of information extraction from quantum systems and propose new measurement protocols with improved information retrieval.
Remember to consider the scope and feasibility of the chosen topic within the constraints of a "bite-size" master's thesis. Consult with your advisor or professors to refine the ideas, identify research gaps, and determine which topic aligns best with your interests and available resources.