Part 7/10:
Von Neumann entropy emerges as a powerful tool in quantum information theory, enabling scientists to quantify the quantum information present within a system. It also offers insights into the nature of entanglement, which plays a significant role in understanding the interplay between entropy and thermodynamics.
Consider the concept of a quantum coin, which, when flipped, enters a superposition—both heads and tails simultaneously—until observed. In this scenario, the entropy is zero prior to measurement because the system's state is entirely defined by the superposition. Upon observation, the system collapses into one outcome, but no new information is revealed about the unrevealed state.