The quantum world refers to the realm of physics that studies the behavior of very small particles, such as atoms and subatomic particles like electrons and photons. 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 between them. This strange behavior contrasts sharply with our everyday experiences governed by classical physics. The principles of the quantum world have led to groundbreaking technologies, including quantum computing and quantum cryptography, which promise to revolutionize information processing and security.