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Topic: Dirac sea

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  Dirac sea - Wikipedia, the free encyclopedia
The Dirac sea is a theoretical model of the vacuum as an infinite sea of particles possessing negative energy.
The Dirac sea interpretation and the "modern" QFT interpretation are related by a Bogoliubov transformation.
Smith's negasphere in Gray Lensman is a fictional interpretation of the Dirac Sea.
en.wikipedia.org /wiki/Dirac_sea   (1145 words)

 Paul Dirac Summary
Dirac shared the Nobel Prize for Physics with Erwin Schrödinger in 1933 for his "discovery of new fertile forms of the theory of atoms and for its applications." Few of Dirac's theories were simple to grasp, and for that reason he had few students during his career.
Dirac was born in Bristol, England on August 8, 1902 to Charles Adrien Ladislas Dirac, a Swiss immigrant, and Florence Hannah (Holten) Dirac, a native of Britain.
Dirac married Margit Wigner of Budapest in 1937.
www.bookrags.com /Paul_Dirac   (5890 words)

 sociology - Sea   (Site not responding. Last check: 2007-10-04)
A sea is a large expanse of saline water connected with an ocean, or a large, usually saline, lake that lacks a natural outlet such as the Caspian Sea and the Dead Sea.
The term is used colloquially as synonymous with ocean, as in the tropical sea or down to the sea shore, or even sea water referring to water of the ocean.
Dirac sea is an interpretation of the negative energy states that comprises the vacuum.
www.aboutsociology.com /sociology/Sea   (218 words)

 Dirac Equation   (Site not responding. Last check: 2007-10-04)
The Dirac equation is an equation for particles with spin-1/2.
Dirac then noticed that if he used a whole collection of wave functions, ordered in a matrix, he could construct an equation which was relativistic, but did not have negative probabilities.
The Dirac equation is thus regarded as an equation for the evolution of the electron field, just as the Klein-Gordon equation is the evolution equation for a spinless field (such as the Higgs field).
www.physto.se /~lbe/enm/diraceq.htm   (573 words)

 Electrodynamic Structure of Space - Part 1
Dirac later realized that a negative energy solution implied the existence of a vast sea of electron/positron pairs that acted as the substrate for all real (observable) electrons and positrons.
Observable electrons and positrons are nothing more than particles pulled lose from this Dirac sea, and represent "defects" (unpaired particles) in the sea, much the same way as electrons and holes arise from intentional defects in a semiconductor material.
In the absence of electro-magnetic fields, the Dirac sea particle pairs must be completely random in their orientation, because any non-random orientation would give rise to an electro-magnetic field.
www.geocities.com /electrogravitics/eds1.html   (1455 words)

 [No title]   (Site not responding. Last check: 2007-10-04)
Dirac´s aim was to find an equation valid for electrons moving with velocities close to that of light (300 000 km/s).
Dirac found in 1930 an ingenious solution to this problem: since electrons obey Pauli's exclusion principle, there can only be one electron in every quantum state.
Dirac thought that this could describe the proton, the only particle with opposite charge from the electron known at the time.
www.physto.se /~lbe/enm/antimatt.htm   (406 words)

 The Dirac Equation and the Positron
Paul Dirac himself suggested that "one should allow oneself to be led in the direction which the mathematics suggests." It takes a great deal of faith to be led by mathematics which produces some seemingly meaningless results, but that faith led Dirac to a correct relativistic electron equation and the prediction of the positron.
Before Dirac invented his equation in 1928 the energy of a particle was modeled by the Shrodinger equation.
At the time Dirac came out with his equation no one wanted to, or had the guts to, suggest that there might be a new particle with a positive charge and the mass of an electron.
www.phy.duke.edu /~kolena/modern/deaton.html   (901 words)

 a naked singularity lies within the Sea of Dirac
As far as I am aware the "sea of Dirac" was a concept that Dirac came up with to explain the existence of antiparticles - which he predicted from relativistic quantum theory.
Dirac noted that the equations (originally formulated for free electrons) permitted negative energy solutions, but if negative energy states were available then surely the electron should "runaway" to these increasingly negative states - radiating off an infinite amount of energy in the process.
Because this sea is always there, and perfectly uniform, it exerts no net force and we are not aware of it.
www.physicsforums.com /showthread.php?t=20993   (747 words)

 Antimatter - Crystalinks
As a way of getting around this, Dirac proposed that the vacuum can be considered a "sea" of negative energy, the Dirac sea.
Dirac himself was the first to consider the existence of antimatter in an astronomical scale.
After Dirac, the sci-fi writers had a field day with visions of antiworlds, antistars and antiuniverses, all made of antimatter, and it is still a common plot device, however suppositions of the existence a coeval, antimatter duplicate of this universe are not taken seriously in modern cosmology.
www.crystalinks.com /antimatter.html   (1002 words)

 [No title]   (Site not responding. Last check: 2007-10-04)
Interpreting the Dirac equation as the equation for the quantum mechanical wave function \psi of the electron, we find the electron has an energy spectrum as follows: we have a continuum of energy levels above E=m, and a continuum of energy levels below E=-m.
Dirac's claim was that in the ``vacuum'' (which means ground state), all the negative energy levels are filled; the vacuum contains a ``Dirac sea'' of an infinite number of negative energy electrons.
Dirac developed the Dirac equation in a quest for a single particle relativistic wave equation, whose conserved charge density would be the probability density to find the single particle at a particular position.
www.emory.edu /PHYSICS/Faculty/Benson/380-96/notes/27.txt   (776 words)

 Dirac equation - Wikipedia, the free encyclopedia
In physics, the Dirac equation is a relativistic quantum mechanical wave equation formulated by British physicist Paul Dirac in 1928 and provides a description of elementary spin-½ particles, such as electrons, consistent with both the principles of quantum mechanics and the theory of special relativity.
In the Dirac representation, the equation for ψ
This is the basis for the use of the Dirac equation in quantum field theory.
en.wikipedia.org /wiki/Dirac_equation   (2936 words)

 Fowler Associates Consulting Testing Training in ESD Electrostatics Radiation and Packaging
Dirac's picture of the energy level distribution of the particles with positive and negative mass.
We must also assume that positive mass electrons can never become negative mass electrons by "falling into a hole in the sea of negative energy states." The converse of this must also be assumed.
The pairing process, fundamental to this model has been considered before by Dirac and is described in Gamow's, "Thirty years that shook physics." Pairing was dismissed due to our inability to confirm it's existence.
www.sfowler.com /authtech/elecmod.htm   (2055 words)

 Antiparticle Summary
Dirac was aware of the problem that his picture implied an infinite negative charge for the universe.
Dirac tried to argue that this was due to the electromagnetic interactions with the sea, until Hermann Weyl proved that hole theory was completely symmetric between negative and positive charges.
A year later, in 1931, Dirac modified his theory and postulated the positron, a new particle of the same mass as the electron.
www.bookrags.com /Antiparticle   (2363 words)

 Tyrannicidae   (Site not responding. Last check: 2007-10-04)
The technical definitions of the quantum vacuum point to a continuous energy sea in which particles of matter are specific substructures.
The zero- ppoint field of the quantum vacuum is a "Dirac- sea": a sea of particles in the negative energy state.
Thus the Dirac- sea is everywhere; the observable universe floats, as it were, on its surface.
groups.msn.com /Tyrannicidae/thequantumvacuum.msnw   (1700 words)

 ipedia.com: Sea Article   (Site not responding. Last check: 2007-10-04)
A sea is a large expanse of saline water connected with an ocean.
A sea (pronounced see) is a large expanse of saline water connected with an ocean.
The term is used in a less geographically precise manner as synonymous with ocean, as in the tropical sea or down to the sea shore, or even sea water referring to water of the ocean.
www.ipedia.com /sea.html   (271 words)

 Hole Theory
The energy-level diagram for solutions of the free Dirac equation is shown in figure 5.1.
At first sight, it may appear that the negative-energy solutions to the Dirac equation are a major problem with the theory.
It is quite clear that despite the success of the hole theory for spin-1/2 particles, the Dirac reinterpretation of the vacuum cannot be applied to spin-0 particles, since bosons are not subject to the Pauli exclusion principle.
www.phys.ualberta.ca /~gingrich/phys512/latex2html/node63.html   (717 words)

 Leliel Twelveth Angel - Of Night
THE "DIRAC SEA": Within Leleil's inverted A.T. Field, is what is best known as the Dirac Sea, a pocket dimension of nothingness.
All attacks are simply absorbed into the Dirac Sea, and absolutely no damage to the Angel.
There is a theoretical boundry to the Dirac Sea, which in actually is within the zebra-stripe ball.
www.angelfire.com /ak4/sentinals/nge/Leleil.htm   (542 words)

 CERN Courier - Research highlights - IOP Publishing - article
Dirac's hole theory was conceptually bizarre and repugnant to Pauli.
While the paper might be viewed merely as a theoretical exercise in the absence of any fundamental scalar charged particles in nature, it was important at the time.
It clarified minds by showing that particles and their antiparticles were not unique to Dirac's theory of electrons and positrons, and that scalar QED gave results similar to spin 1/2 QED.
cerncourier.com /main/article/42/10/21   (2020 words)

 Dirac's Sea, OOPS!!   (Site not responding. Last check: 2007-10-04)
Particle theory says that for every fermion type there is another fermion type that has exactly the same mass, and therefore no priori distinction between matter and anti-matter.
Dirac's "Sea of Electrons" was dismissed as implausible for this reason, but the opposite value of all other charges (quantum numbers), indicates that the asymmetry between the two classes of particles is due to the fact that the anti-particle has -rho and negative mass, until it becomes a real particle.
Vacuum energy density, (rho), is related to pressure by P=-rho, and so vacuum expansion will be affected by pair production, as the negative pressure component increases in proportion to the "hole", while the gradient between the vacuum and matter becomes more severe via the gravitaionally offset increase in vacuum tension.
www.lns.cornell.edu /spr/2003-11/msg0056253.html   (180 words)

The origins of the Dirac sea lie in the energy spectrum of the Dirac equation, a special case of the Schrdinger equation that is consistent with special relativity, that Dirac had formulated in 1928.
However, it becomes serious when we start to think about how to include the effects of the electromagnetic field, because a positive-energy electron would be able to shed energy by continuously emitting photons, a process that could continue without limit as the electron descends into lower and lower energy states.
sea of dirac, it's an honor to be among your friends!
www.myspace.com /seaofdirac   (1062 words)

 Isovector dipole excitations in the relativistic RPA
Configuration space that include only pairs formed by excitations of particle from the Fermi sea to a higher state above the Fermi level is not sufficient for successful description of giant resonances.
Pb is shown in the Fig.1, separately for calculations without and with Dirac states contributions due to exchange of scalar and vector mesons.
Therefore in the further analysis, we apply the full self-consistent RRPA including in addition to the ordinary p-h excitations, the antiparticle-hole excitations from the occupied Fermi to the empty Dirac sea.
www.phy.hr /~npaar/pygmy/node2.html   (619 words)

Regarding the physics of the metric: in 1949 some kind of crystal-like Dirac sea was shown to mimic the SR contraction and mass-energy variation, see C.F. Frank, ‘On the equations of motion of crystal dislocations’, Proceedings of the Physical Society of London, A62, pp 131-4:
Additionally, Woit stated other clues of chiral symetry: ‘The SU(2) gauge symmetry is supposed to be a purely internal symmetry, having nothing to do with space-time symmetries, but left and right-handed spinors are distinguished purely by their behavior under a space-time symmetry, Lorentz symmetry.
He presented his first paper before an audience which included Dirac (although unfortunately Dirac was then old and slept right through).  He has a vast literature survey and collection of vitally informative quotations from authorities, as well as new insights from his own work in quantum mechanics and field theory.
nige.wordpress.com   (10887 words)

 exploring vacuum   (Site not responding. Last check: 2007-10-04)
Consequently, the vacuum consisted of a “Dirac sea” of an infinite number of electrons filling all the negative energy levels, while the positive energy levels were empty.
However, this prediction of particle-antiparticle pairs by Dirac came as a result of trying to overcome the problem of negative energy in the equations.
There are those who still hold to the “Dirac sea” model for the vacuum, but as Henning Genz, professor of theoretical physics at the University of Karlsruhe, Germany stated: “The infinite sea of electrons in the Dirac vacuum, with their negative energy and their infinite charge, cannot be the answer.
www.setterfield.org /exploringvacuum.htm   (11627 words)

 Mechanism of Standard Model particle mass, gauge boson forces and General Relativity
Firstly, the spacetime fabric of general relativity needs to be unified with the Dirac sea of quantum field theory.
Coupling between the electron and the Dirac sea causes the 1 + 1/(twice Pi times 137) = 1.00116 Bohr magnetons quantum electrodynamic first correction to the magnetic moment of the electron core, which Dirac's theory gives wrongly as exactly 1 Bohr magneton.
In Dirac’s sea, there are pairs of virtual particles which annihilate rapidly because they don’t have enough energy to escape and become real.
electrogravity.blogspot.com /2006/04/whole-unification-business-is.html   (11647 words)

Migratory Patterns of The Dirac Sea has 226 friends.
View All of Migratory Patterns of The Dirac Sea 's Friends
I soon, will be in Migratory Patterns of The Dirac Sea.
www.myspace.com /mpds   (339 words)

 Sea of Dirac   (Site not responding. Last check: 2007-10-04)
In a sea of positively charged electrons, he swims
To the origin of symmetry, where loneliness is a blessing in disguise
The contents of this page have not been reviewed or approved by the University of Minnesota.
www.tc.umn.edu /~moha0117/dirac.htm   (147 words)

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