The three primary principles underlying all quantum phenomena are:
Superposition: Superposition is a fundamental principle in quantum mechanics that states that a quantum system can exist in multiple states simultaneously. Unlike classical systems that have definite states, quantum systems can be in a superposition of different states. For example, a qubit, the basic unit of quantum information, can exist in a superposition of both 0 and 1 states simultaneously. Superposition allows quantum systems to perform parallel computations and explore multiple possibilities simultaneously.
Entanglement: Entanglement is a phenomenon that occurs when two or more quantum particles become correlated in such a way that the state of one particle cannot be described independently of the state of the other particles, regardless of the physical distance between them. The entangled particles are instantaneously connected, even if they are separated by large distances. Changes in the state of one particle instantaneously affect the state of the other, regardless of the distance between them. Entanglement is a crucial resource for various quantum applications, including quantum communication and quantum computation.
Quantum Measurement: Quantum measurement is the process by which the state of a quantum system is determined or observed. According to the principles of quantum mechanics, the act of measurement causes the superposition of a quantum system to "collapse" into one of its possible states. The measurement outcome is probabilistic, and the probabilities are determined by the quantum state of the system. This principle introduces inherent randomness into quantum systems and sets limits on the predictability of their behavior.
These three principles—superposition, entanglement, and quantum measurement—form the foundation of quantum mechanics and are central to understanding and harnessing the unique properties of quantum systems. They underpin the development of quantum technologies, such as quantum computing, quantum communication, and quantum sensing.