Quantum physics, also known as quantum mechanics, is a branch of physics that deals with the behavior of matter and energy at the smallest scales, such as atoms and subatomic particles. It is a fundamental theory that describes the nature of particles and their interactions based on quantum principles.
Quantum physics departs from classical physics, which is based on classical mechanics and deterministic laws. In contrast, quantum mechanics introduces probabilistic behavior and describes particles and systems using wave-like properties.
The key principles of quantum physics include:
Wave-particle duality: Quantum theory proposes that particles, such as electrons and photons, can exhibit both wave-like and particle-like behavior. They can be described by wavefunctions, which represent the probability distribution of finding a particle at a particular location or with a particular energy.
Superposition: Quantum systems can exist in multiple states simultaneously, known as superposition. This means that a particle can be in multiple positions or possess multiple energy states simultaneously until measured or observed.
Uncertainty principle: The uncertainty principle, formulated by Werner Heisenberg, states that certain pairs of physical properties, such as position and momentum, cannot be precisely known simultaneously. There is a fundamental limit to the precision with which certain pairs of properties can be measured.
Quantum entanglement: Entanglement refers to the phenomenon where two or more particles become correlated in such a way that the state of one particle cannot be described independently of the others. Measuring one entangled particle can instantaneously affect the state of the other, regardless of the distance between them.
Quantum measurements and collapse of the wavefunction: When a measurement is made on a quantum system, the wavefunction "collapses" into one of the possible states, randomly determined according to the probabilities defined by the wavefunction.
Quantum physics has wide-ranging applications in various fields, including electronics, computing, telecommunications, material science, and quantum chemistry. It provides a powerful framework for understanding and predicting the behavior of particles at the atomic and subatomic levels, leading to technological advancements and deepening our understanding of the fundamental nature of reality.