The "Quantum World" refers to the realm of physics that studies the behavior of matter and energy at the smallest scales, such as atoms and subatomic particles. In this world, particles can exist in multiple states at once, a phenomenon known as superposition. Additionally, particles can be entangled, meaning the state of one particle can instantly affect another, regardless of the distance separating them. This field of study is governed by the principles of quantum mechanics, which challenge our classical understanding of physics. Key concepts include wave-particle duality, where particles exhibit both wave-like and particle-like properties, and the uncertainty principle, which states that certain pairs of physical properties cannot be simultaneously known with precision.