Quantum physics is a 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, and can be interconnected through entanglement, meaning the state of one particle can instantly affect another, regardless of distance. This field challenges our traditional understanding of physics, which is based on classical mechanics. Quantum mechanics has led to significant technological advancements, including semiconductors, lasers, and quantum computing, which harness the unique properties of particles to perform complex calculations much faster than conventional computers.