Quantum Physics & Quantum Mechanics

Quantum mechanics (QM) is a branch of physics describing the behavior of energy and matter at the atomic and subatomic scales. The name derives from the observation that the energy of an electron bound into an atom or molecule—can be changed only by discrete amounts, or quanta, rather than being capable of varying by any amount. Photons are the quanta of light, and have energy values proportional to their frequency. An electron bound in an atomic orbital has quantized values of angular momentum and energy. The unbound electron does not exhibit quantized energy levels, but is associated with a quantum mechanical wavelength, as are all massive particles.

The ground state in quantum mechanical model is a Zero-Point Energy state that is the lowest permitted energy state of a system. Generally, it contains no physical particles.

According to present-day understanding of what is called Zero-Point Field or the quantum vacuum, it is "by no means a simple empty space", and again: "it is a mistake to think of any physical vacuum as some absolutely empty void." According to quantum mechanics, the vacuum state is not truly empty but instead contains fleeting electromagnetic waves and particles that pop into and out of existence.