# What is Fermi dirac statistics?

It would be difficult to understand the behavior of electrons without the Fermi Dirac statistics. Why in a metal, electrons can move freely to conduct the electric current and why their contribution in the same metal to the specific heat is negligible, as if their number become for an unknown reason, considerably reduced. We have here a problem of "statistical order" that can be explained only by using the Fermi Dirac statistics (the classical statical mechanics was unable to explain this phenomenon).

### What famous theory did Albert Einstein come up with?

I've got to pick one? Okay, let's go with General Relativity then. There's also Special Relativity, and some work with statistics (giving rise to something called Bose-Einstein statistics, the counterpart to Fermi-Dirac statistics; subatomic particles follow one or the other depending on what type they are).

### Why fermi level is found in the energy gap region since this region is forbidden for electrons and how does its probability is half?

The Fermi level is also known as the electron chemical potential (μ), and is a constant appearing in the Fermi-Dirac distribution formula: F() = 1 / [1 + exp((-μ)/kT)] Even though the gap may not contain any electronic states, there may be some thermally excited holes in the valence band and electrons in the conduction band, with the occupancy given by the Fermi-Dirac (FD) function. By inspecting the FD function, it becomes clear that if…

### What is the main difference between Classical free Electron theory and Quantum free Electron theory?

Electrons are fermions and thus cannot occupy the same quantum states. They obey Fermi-Dirac statistics, and will occupy energy levels accordingly. This is different to the classica state where all electrons are pretty much equal (equal energies etc) and are not taken to be distrubuted amongst multiple states and energies. See Fermi Gas Model for a treatment of quantum free electron theory.

### What is Fermi-Dirac distribution function?

There are two different kinds of particles (electrons, protons, neutrons, atoms, molecules). Each such particle has a so called "spin" which is quantum mechanical value. Depending on spin particles behave differently in the same conditions and can be described using two different distributions. First one is Bose-Einstein distribution for particles with integer spin. Second on is Fermi-Dirac distribution for particles with spin n/2 (where n is an integer number which can take values starting from…

### What stops the collapse in neutron stars?

The Fermi-Dirac statistics stops the collapse, or the Pauli exclusion principle to be exact. The principle states that no two fermions can exist in the same energy state at the same time. Neutron stars are almost pure neutron degenerate matter and neutrons are fermions. As you compress degenerate matter, you get outward pressure because the electrons don't want to occupy the same energy states as other neutrons.

### Is Universe homogeneous or heterogeneous?

Heterogeneous because it is composed of many different states of matter (solids, liquids, gases). These can be physically separated easily. This question needs more explanation. You could argue that it is both. All mass is energy, for example, and so the universe is made of energy, radiating in all space. It is divisible, however, into the elementary particles of which there are many. From there you could also argue that the universe is comprised of…

### Explain fermi dirac statistic and distribution for semiconductor?

The conduction band in a piece of semiconductor consists of mainly available, empty energy levels. When calculating how many electrones will fil these levels and thus be counted in n, contributing to conductivity , we consider two factors : * How many energy levels are there within a given range of energy, in our case the conduction band . * How likely is that each level will be populated by an electron . The likelihood…

### Who has the greatest contribution in quantum mechanics among Heisenberg and Dirac and Schrodinger?

Heisenberg, Dirac and Schrodinger all made large combinations. Schrodinger is famous for his wave mechanics, Heisenberg for his matrix notation. Dirac realised that the theories of Heisenberg and Schrodinger were essentially the same. He also created the Dirac equation, an important step in the creation of a relativistic version of Quantum Mechanics.

### What has the author Enrico Fermi written?

Enrico Fermi has written: 'Elementary particles' -- subject(s): Constitution, Matter, Particles 'New Directions in Quantum Chaos (International School of Physics \\' 'Notes on thermodynamics and statistics' -- subject(s): Statistical thermodynamics 'Notes on quantum mechanics' -- subject(s): Quantum theory 'Collected papers' -- subject(s): Collected works, Physics

### Who is the father of quantum mechanics?

Max Planck is not only the father of quantum mechanics.Those who took part in the discovery of quantum mechanics are known as founding fathers and they are Planck, Einstein, Bohr, Heisenberg, Born,Jordan, Pauli, Fermi, Schrodinger, Dirac, de Broglie, Bose. They all made notable contributions. Note: Quantum mechanics is not only the invention of one or two scientists.