Quantum State Visualizer: An Interactive Tool for Multi-Qubit System Analysis Using Partial Trace and Bloch Sphere Representation

Quantum state visualisation remains a significant challenge in quantum computing education and research due to the abstract mathematical properties of quantum mechanics. This paper presents a new Quantum State Visualiser, an interactive web app that tries to bridge the gap between theoretical quantum mechanics and real-world understanding. The proposed solution operates with multi-qubit quantum circuits, employing partial trace operations to derive single-qubit reduced density matrices, which are then depicted as dynamic 3D Bloch sphere representations. The tool helps you understand abstract ideas like superposition, entanglement, and quantum interference by turning hard math into easy-to-understand pictures. This is useful for students, teachers, researchers, and people who work on quantum computers.The prototype uses Qiskit for quantum Traditional quantum co simulation, Python for computational backends, and modern web technologies for interactive visualisation. The system can accurately show quantum states in real time, which means that circuit changes get instant visual feedback. The new thing is that it combines quantum simulation in real time with 3D visualisation that you can interact with. This creates a fun place to learn that helps people understand quantum phenomena faster. This tool fills a big gap in education and could be used in schools, to fix problems with quantum algorithms, and to make quantum circuits work better. In the future, it will be possible to work with bigger qubit systems, connect it to quantum hardware platforms, and add features for augmented reality visualisation