Quantum physics is the branch of science that studies the behavior of matter and energy at the smallest scales, such as atoms and subatomic particles. It reveals that particles can exist in multiple states at once, a concept known as superposition. This means that, unlike larger objects, tiny particles do not have definite positions or velocities until they are measured. Another key principle of quantum physics is entanglement, where particles become interconnected in such a way that the state of one instantly influences the state of another, regardless of the distance between them. These phenomena challenge our traditional understanding of physics and have led to advancements in technologies like quantum computing and quantum cryptography.