Search results
Results from the WOW.Com Content Network
The ground state of a quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state. In quantum field theory, the ground state is usually called the vacuum state or the vacuum. If more ...
This implies that the ground state is the only occupied state for electrons in the limit , the = takes the Pauli exclusion principle into account. The internal energy U {\displaystyle U} of a system within the free electron model is given by the sum over one-electron levels times the mean number of electrons in that level:
Quantum mechanics uses the word 'degenerate' in two ways: degenerate energy levels and as the low temperature ground state limit for states of matter. [3]: 437 The electron degeneracy pressure occurs in the ground state systems which are non-degenerate in energy levels. The term "degeneracy" derives from work on the specific heat of gases that ...
Electrons can relax into states of lower energy by emitting electromagnetic radiation in the form of a photon. Electrons can also absorb passing photons, which excites the electron into a state of higher energy. The larger the energy separation between the electron's initial and final state, the shorter the photons' wavelength. [4]
At low temperatures, the electrons of solid materials can also organize into various electronic phases of matter, such as the superconducting state, with vanishing resistivity. Magnetic states such as ferromagnetism and antiferromagnetism can also be regarded as phases of matter in which the electronic and nuclear spins organize into different ...
Matter in the plasma state has variable volume and shape, and contains neutral atoms as well as a significant number of ions and electrons, both of which can move around freely. The term phase is sometimes used as a synonym for state of matter, but it is possible for a single compound to form different phases that are in the same state of matter.
Fire ants sting and bite, particularly little kids since they can come into contact with dirt mounds playing outside. During those rare summer showers, fire ants will immediately turn up.
In the quantum-mechanical description, matter at absolute zero is in its ground state, the point of lowest internal energy. The laws of thermodynamics show that absolute zero cannot be reached using only thermodynamic means, because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically. [4]