The maximum energy that an electrons can have at absolute zero is called the Fermi energy.

The Fermi temperature is defined as this maximum energy divided by Boltzmann's constant, and is of the order of 80, 000 K for typical electron densities found in metals.

The BCS theory gives an expression that shows how the gap grows with the strength of the attractive interaction and the ( normal phase ) single particle density of states at the Fermi energy.

Furthermore, it describes how the density of states is changed on entering the superconducting state, where there are no electronic states any more at the Fermi energy.

BCS theory relates the value of the critical field at zero temperature to the value of the transition temperature and the density of states at the Fermi energy.

: Here N ( 0 ) is the electronic density of states at the Fermi energy.

Russian physicist Lev Landau used the idea for the Fermi liquid theory wherein low energy properties of interacting fermion systems were given in terms of what are now known as Landau-quasiparticles.

In 1923, while writing the appendix for the Italian edition of the book The Mathematical Theory of Relativity by A. Kopff, Enrico Fermi pointed out, for the first time, that hidden inside the famous Einstein equation (), there was an enormous amount of nuclear potential energy to be exploited.

Unfortunately, in such calculations, Fermi did not take into account the " pairing energy " that might appear when a nuclide with an odd number of neutrons absorbed an extra neutron.

In both of these models the electrons are seen as a gas traveling through the lattice of the solid with an energy that is essentially isotropic in that it depends on the square of the magnitude, not the direction of the momentum vector k. In three-dimensional k-space, the set of points of the highest filled levels ( the Fermi surface ) should therefore be a sphere.

The Fermi level is the energy below which there is a 50 % chance of finding an occupied energy state.

States with energy ε below the Fermi level, here µ, have higher probability n to be occupied, and those above are less likely to be occupied.

The distribution is characterized by the temperature of the electrons, and the Fermi level At absolute zero temperature the Fermi level can be thought of as the energy up to which available electron states are occupied.

At higher temperatures, the Fermi level is the energy at which the probability of a state being occupied has fallen to 0. 5.

If the bias is small, we can let U − E ≈ φM in the expression for κ, where φM, the work function, gives the minimum energy needed to bring an electron from an occupied level, the highest of which is at the Fermi level ( for metals at T = 0 kelvins ), to vacuum level.

One can sum the probability over energies between E < sub > f </ sub > − eV and E < sub > f </ sub > to get the number of states available in this energy range per unit volume, thereby finding the local density of states ( LDOS ) near the Fermi level.

This process, known as the " Second Order Fermi Mechanism ", increases particle energy during head-on collisions, resulting in a steady gain in energy.

With the nonlinear component, Fermi expected energy in one mode to transfer gradually to other modes, and eventually, to be distributed equally among all modes.

Simple Band Diagram with denoted vacuum energy E < sub > VAC </ sub >, conduction band E < sub > C </ sub >, Fermi energy E < sub > F </ sub >, valence band E < sub > V </ sub >, electron affinity E < sub > ea </ sub >, work function Φ and band gap E < sub > g </ sub >

In solid-state physics, the work function ( sometimes spelled workfunction ) is the minimum energy ( usually measured in electronvolts ) needed to remove an electron from a solid to a point immediately outside the solid surface ( or energy needed to move an electron from the Fermi level into vacuum ).

One model that estimates the properties of an electron gas at absolute zero in metals is the Fermi gas.

Note that the above formula is only applicable to classical ideal gases and not Bose – Einstein or Fermi gases.

Baryons are strongly interacting fermions — that is, they experience the strong nuclear force and are described by Fermi − Dirac statistics, which apply to all particles obeying the Pauli exclusion principle.

The green curve uses the general pressure law for an ideal Fermi gas, while the blue curve is for a non-relativistic ideal Fermi gas.

The Drake equation is closely related to the Fermi paradox in that Drake suggested that a large number of extraterrestrial civilizations would form, but that the lack of evidence of such civilizations ( the Fermi paradox ) suggests that technological civilizations tend to disappear rather quickly.

Fermi is widely regarded as one of the leading scientists of the 20th century, highly accomplished in both theory and experiment.

If this sounds like hyperbole, anything about Fermi is likely to sound like hyperbole ".

He also mused about a proposition which is now referred to as the " Fermi Paradox ".

* Fermi Court in Deep River, Ontario is named in his honor.

is: Enrico Fermi

In particle physics, a fermion ( a name coined by Paul Dirac from the surname of Enrico Fermi ) is any particle characterized by Fermi – Dirac statistics and following the Pauli exclusion principle ; fermions include all quarks and leptons, as well as any composite particle made of an odd number of these, such as all baryons and many atoms and nuclei.

The Fermi paradox ( or Fermi's paradox ) is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilization and humanity's lack of contact with, or evidence for, such civilizations.

In an informal discussion in 1950, the physicist Enrico Fermi questioned why, if a multitude of advanced extraterrestrial civilizations exists in the Milky Way galaxy, evidence such as spacecraft or probes is not seen.

A more detailed examination of the implications of the topic began with a paper by Michael H. Hart in 1975, and it is sometimes referred to as the Fermi – Hart paradox.

The Fermi paradox is a conflict between an argument of scale and probability and a lack of evidence.

The second cornerstone of the Fermi paradox is a rejoinder to the argument by scale: given intelligent life's ability to overcome scarcity, and its tendency to colonize new habitats, it seems likely that at least some civilizations would be technologically advanced, seek out new resources in space and then colonize first their own star system and subsequently the surrounding star systems.

While numerous theories and principles are related to the Fermi paradox, the most closely related is the Drake equation.

In 1922, he published his first important scientific work in the Italian journal I Rendiconti dell ' Accademia dei Lincei entitled " On the phenomena occurring near a world line ", where he introduces for the first time the so-called " Fermi coordinates ", and proves that when close to the time line, space behaves as a euclidean one.

At age 24, Fermi took a professorship at the University of Rome ( one of the first three in theoretical physics in Italy ) which he won in a competition whose selection committee was chaired by Professor Orso Mario Corbino, director of the Institute of Physics.

In 1934 Fermi published his theory of beta decay, later referred to as Fermi's interaction and ( still later ) the theory of the " weak interaction " ( one of the 4 basic forces in nature, then brand new ).

Fermi went home for lunch one day and returned with the explanation: the increased activity was due to hydrogen atoms in the wood slowing down neutrons ( later called moderation ) and this slowing caused them to be more active in nuclear reactions.

The well-known historian of physics, C. P. Snow, says about him, " If Fermi had been born a few years earlier, one could well imagine him discovering Rutherford's atomic nucleus, and then developing Bohr's theory of the hydrogen atom.

Enrico Fermi had been the first to use a neutron to produce the radioactive change of one element to another.

It was discovered in the debris of the first hydrogen bomb explosion in 1952, and named after Nobel laureate Enrico Fermi, one of the pioneers of nuclear physics.

They then had a more serious discussion regarding the chances of humans observing faster-than-light travel by some material object within the next ten years, which Teller put at one in a million, but Fermi put closer to one in ten.

Enrico Fermi, who developed the theory of beta decay, coined the term neutrino ( the Italian equivalent of " little neutral one ") in 1933 as a way to resolve the confusion.

Amongst these, world-renowned physicists Emilio Segrè, Enrico Fermi ( whose wife was Jewish ), Bruno Pontecorvo, Bruno Rossi, Tullio Levi-Civita, mathematicians Federigo Enriques and Guido Fubini and even the fascist propaganda director, art critic and journalist Margherita Sarfatti, who was one of Mussolini's mistresses.

Italian physicist Enrico Fermi suggested in the 1950s that if technologically advanced civilizations are common in the universe, then they should be detectable in one way or another.

The two books show at least one solution to the Fermi paradox, with electromagnetically noisy civilisations being snuffed out by the arrival of self-replicating machines designed to destroy any potential threat to their ( possibly long-dead ) creators.

Because the technique is sensitive to the angle of the emitted electrons one can determine the spectrum for different wave vectors on the Fermi surface.

Robert Hofstadter coined the term fermi ( unit ), symbol fm, in honor of the Italian physicist Enrico Fermi ( 1901 – 1954 ), one of the founders of nuclear physics, in Hofstadter's 1956 paper published in the Reviews of Modern Physics journal, " Electron Scattering and Nuclear Structure ".

Specifically, one can define the ( Earth-referenced ) electrochemical potential μ < sub > A </ sub > of a body " A " as the work needed to transfer an electron from the Fermi level of the Earth to the Fermi level of body " A ".

If the capacitor is uncharged, the Fermi level is the same on both sides, so one might think that it should take no energy to move an electron from one plate to the other.

Confusion arises because there is no accepted international nomenclature for the three different logical entities called " Fermi level ", and because in each of the main contexts in which one of these entities is used it is often just called " Fermi level ".

The Fermi energy ( E < sub > F </ sub >) of a system of non-interacting fermions is the increase in the ground state energy when exactly one particle is added to the system.