The Pauli exclusion principle helps to explain and understand both the structure and the chemical properties that atoms possess.
Pauli exclusion principle is the name given to content linked to the field of quantum mechanics . The name of this expression refers to the surname of a theoretical physicist of Austrian origin since it was he, a man named Wolfgang Pauli who obtained Swiss and American citizenship, who formulated it in 1925.
This rule, indicated as a derivation of a theorem focused on the correspondence between statistics and spin , indicates that in the same quantum system it is not possible to register a pair of fermions that has a quantum state identical to each other (that is, with equality in matter). of quantum numbers ).
As can be seen when reviewing the evolution that this reasoning has undergone, the Pauli exclusion principle was born as an explanation regarding the structure of the atom and how the periodic table is organized. At that time it marked a restriction regarding the location of electrons in different quantum states . Over time, a distinction was made between fermions (for which the Pauli principle does apply) and bosons (particles for which this principle does not apply given that they have integer spin).
History of the Pauli exclusion principle
The history of the formulation of the Pauli exclusion principle began once Wolfgang Ernst Pauli began to investigate with the purpose of explaining both certain numbers of the Bohr atomic model as well as experimental consequences associated with the Zeeman effect in the phenomenon classified as ferromagnetism. and in atomic spectroscopy .
His analyzes and deductions gained an inspiring impulse in a work that came to light in 1924 with the English theoretical physicist Edmund Clifton Stoner as its author. Based on this work, Pauli proposed the idea of, if the states of electrons are defined in terms of two pairs of quantum numbers , identifying them based on one electron for each state. In this context, he proposed a new quantum number based on two values that George Uhlenbeck and Samuel Goudsmit baptized as electron spin. His scientific findings and contributions, especially the formulation of the exclusion rule, earned him a Nobel Prize in Physics in 1945.
Due to the Pauli exclusion principle, neutrons degenerate and a pressure arises that stops the contraction of the core of a neutron star before giving way to a black hole.
Applications
The quantum universe is best understood thanks to the Pauli exclusion principle , which has a wide variety of applications .
This content contributes to understanding how neutron stars can remain in equilibrium and is involved in the electronic configuration of atoms . Likewise, it influences certain properties that characterize elements in a solid state. In this framework, we cannot fail to point out the existence of molecular orbitals forming, both in conductors and semiconductors , a structure of energy bands. In metals (elements classified as strong conductors), a marked degeneracy of electrons is observed.
It is present, in the same way, in the stability achieved in systems that involve numerous nucleons and electrons .
The Pauli exclusion principle is key to, for example, understanding the order of the elements within the periodic table.
Experiments linked to the Pauli exclusion principle
Over the years, experiments linked to the Pauli exclusion principle have been carried out, both to ratify it and to confirm its scope or demonstrate eventual or possible violations.
Seasons ago, a project of international interest that was called the VIP2 experiment was launched on Italian soil, specifically at the Gran Sasso National Laboratory , for example. The challenge of this plan has been to search for new quantum states in which, in a state of antisymmetric character, some symmetric element is observed. The data collected has aimed to facilitate the analysis of energy spectra in areas where a violation of the transitions between states considered "prohibited" could be expected.
On the other hand, an effect derived from the Pauli exclusion principle has been investigated, which was identified as "Pauli blockade" evidenced when the atoms cool down. Taking advantage of it, the dream that many people have in relation to the chance of inventing a layer that ensures the invisibility of matter (that is, of objects) could come true.
A group of physicists, to describe another relevant fact in a descriptive way, has worked with a quantum computer with the aim of achieving greater precision about how electrons in molecules behave at a quantum level. In this scenario, several quantum states were created in which violations of the Pauli restrictions were very occasionally detected. And when the results of this research were officially announced, it was indicated that it was at the beginning of the '70s when the simplest restrictions could be confirmed on a theoretical level by using classical computer equipment at IBM . These modern findings, experts considered, will serve to improve the efficiency of quantum calculations and to design more precise schemes that focus on error correction, something key to getting the most out of quantum computers .