Read the dialogue below:

Person A: Have you been keeping up with the latest advancements in quantum computing? The concept of qubits and entanglement is revolutionizing computational possibilities.
Person B: Absolutely, it's intriguing how superposition allows qubits to exist in multiple states simultaneously, vastly increasing the computational capacity. However, the challenges in maintaining coherence within these systems remain a critical hurdle.

Based on the dialogue, what is the primary innovation being discussed regarding quantum computing, and what are the challenges associated with this innovation?