Simulation and estimation of the capacity of four qubit GHZ state superdense coding protocol on the platform of IBM Quantum Computer

This article introduces an innovative four-qubit GHZ state protocol for superdense quantum coding, aimed at maximizing the capacities of quantum systems.The coding capacity was theoretically compared to the Holevo bound, which defines the limit of extractable information from a quantum system.Simulations were performed using quantum computing software, followed by implementation on the IBM Quantum Computer to assess both theoretical and practical outcomes.Experimental findings revealed a slight deviation from theoretical predictions: while theory assigned a 50% probability to each state, practical results indicated 50.19531% and 49.80469%.These differences are attributed to environmental noise and qubit interactions, which pose challenges in quantum computing.The study highlights the need for strategies to mitigate noise and enhance measurement precision.Results were presented using bar charts, facilitating clear data analysis and revealing patterns better.Overall, this research provides a new protocol and addresses key challenges in quantum technology, contributing significantly to the field of quantum computing and paving the way for future advancements.