Quantum physics, also known as quantum mechanics, is a branch of physics that describes the behavior of matter and energy at the smallest scales, such as atoms and subatomic particles. It is different from classical physics, which describes the behavior of macroscopic objects like everyday objects and their interactions.
The fundamental distinction between quantum physics and classical physics arises from the concept of wave-particle duality. In quantum mechanics, particles like electrons and photons exhibit both wave-like and particle-like properties. This means that they can behave as discrete particles in certain situations and as waves with wave-like characteristics in others. This wave-particle duality is not observed in classical physics, where objects are typically considered purely particles or purely waves.
Quantum mechanics is also characterized by probabilistic behavior. In classical physics, if we know the initial conditions of a system and the forces acting upon it, we can predict its future behavior deterministically. However, in quantum mechanics, the behavior of particles is described by a wave function that gives the probability distribution of finding the particle in different states. The outcome of a measurement in quantum mechanics is inherently probabilistic, with different possible outcomes occurring with specific probabilities.
The differences between quantum physics and classical physics arise from the fundamental principles and mathematical formalism of quantum mechanics, such as superposition, uncertainty principle, and wave function collapse. These principles were developed to explain the experimental observations that did not align with classical physics, particularly when studying the behavior of particles at the microscopic level.
It is worth noting that while quantum physics introduces new concepts and rules, it reduces to classical physics in macroscopic systems where quantum effects become negligible due to a large number of particles involved. In such cases, classical physics accurately describes the behavior of the system.
Quantum physics is a highly successful and well-tested theory, supported by numerous experiments and applications in various fields such as electronics, materials science, and quantum computing. Its departure from classical physics is a result of our deepening understanding of the fundamental nature of reality at the quantum scale.