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The full name is Program for Atomic and Molecular Direct Iterative Relativistic All-electron Calculations, in short PAM DIRAC. It is capable of calculating various molecular properties using the Hartree–Fock , MP2 , density functional theory , configuration interaction and coupled cluster electronic structure theories.
In particle physics, the Dirac equation is a relativistic wave equation derived by British physicist Paul Dirac in 1928. In its free form, or including electromagnetic interactions, it describes all spin-1/2 massive particles, called "Dirac particles", such as electrons and quarks for which parity is a symmetry.
Paul Adrien Maurice Dirac was born at his parents' home in Bristol, England, on 8 August 1902, [43] and grew up in the Bishopston area of the city. [44] His father, Charles Adrien Ladislas Dirac, was an immigrant from Saint-Maurice, Switzerland, of French descent, [45] who worked in Bristol as a French teacher.
The BBC's reference implementation, initially called Dirac but renamed dirac-research to avoid confusion, was written in C++ and released under the Mozilla Public License, GNU GPL 2 and GNU LGPL free software licenses. Version 1.0.0 of this implementation was released on 17 September 2008 and defines the Dirac bitstream format. [7]
In physics, particularly special relativity, light-cone coordinates, introduced by Paul Dirac [1] and also known as Dirac coordinates, are a special coordinate system where two coordinate axes combine both space and time, while all the others are spatial.
A Dirac comb is an infinite series of Dirac delta functions spaced at intervals of T. A so-called uniform "pulse train" of Dirac delta measures, which is known as a Dirac comb, or as the Sha distribution, creates a sampling function, often used in digital signal processing (DSP) and discrete time signal analysis
When applying canonical quantization on a constrained Hamiltonian system, the commutator of the operators is supplanted by iħ times their classical Dirac bracket. Since the Dirac bracket respects the constraints, one need not be careful about evaluating all brackets before using any weak equations, as is the case with the Poisson bracket.
where is the charge conjugation matrix, which matches the Dirac version defined above. The reason for making all gamma matrices imaginary is solely to obtain the particle physics metric (+, −, −, −), in which squared masses are positive. The Majorana representation, however, is real.