How do field descriptions differ in quantum physics?

In quantum physics, field descriptions differ as they are probabilistic and involve wave-particle duality.

In classical physics, fields such as electric and magnetic fields are described deterministically. This means that if we know the initial conditions of a system, we can predict with certainty the future behaviour of the system. However, in quantum physics, fields are described probabilistically. This is a fundamental aspect of quantum mechanics, where the exact state of a system cannot be known with certainty. Instead, we can only calculate the probability of finding a system in a particular state. This is often represented mathematically using wave functions.

Moreover, quantum field theory introduces the concept of wave-particle duality. This is the idea that all particles also have wave-like properties, and all waves have particle-like properties. This is a significant departure from classical physics, where particles and waves are distinct entities. In quantum field theory, particles are seen as excitations of the underlying quantum field. For example, photons are excitations of the electromagnetic field, and electrons are excitations of the electron field.

Another key difference is the role of observers in quantum physics. In classical physics, the observer is considered separate from the system being observed and does not affect it. However, in quantum physics, the act of observation can change the state of the system. This is known as the observer effect or the measurement problem.

Finally, quantum fields also allow for the creation and annihilation of particles. This is a process where energy can be converted into particles and vice versa, which is not possible in classical physics. This is described by the famous equation E=mc^2, which shows the equivalence of energy (E) and mass (m). This is another unique aspect of quantum field descriptions that sets them apart from their classical counterparts.