supersymmetry

Definition 0.1.

Supersymmetry or Poincaré, (extended) quantum symmetry is usually defined as an extension of ordinary spacetime symmetries obtained by adjoining $N$ spinorial generators $Q$ whose anticommutator yields a translation generator: $\{Q,Q\}=\left\{P\right\}$.

As further explained in ref. [1]:

“This (super) symmetry…(of the superspace)… can be realized on ordinary fields (that are defined as certain functions of physical spacetime(s)) by transformations that mix bosons and fermions. Such realizations suffice to study supersymmetry (one can write invariant actions, etc.) but are as cumbersome and inconvenient as doing vector calculus component by component. A compact alternative to this ‘component field’ approach is given by the superspace–superfield approach”, which is defined next.

Definition 0.2.

Quantum superspace, or superspacetimes, can be defined as an extension(s) of ordinary spacetime(s) to include additional anticommuting coordinates, for example, in the form of $N$ two-component Weyl spinors $\theta$.

Definition 0.3.

(Quantum) superfields $\mathrm{\Psi }(x,\theta )$ are functions defined over such superspaces, or superspacetimes. Taylor series expansions of the superfield functions can be then performed with respect to the anticommuting coordinates $\theta$; this Taylor series has only a finite number of terms and the series expansion coefficients obtained in this manner are the ordinary ‘component fields’ specified above.

Remarks: Supersymmetry is expected to be manifested, or observable, in such superspaces, that is, the supersymmetry algebras are represented by translations and rotations involving both the spacetime and the anticommuting coordinates. Then, the transformations of the ‘component fields’ can be computed from the Taylor expansion of the translated and rotated superfields. Especially important are those transformations that mix boson and fermion symmetries; further details are found in ref. [2].

Title	supersymmetry
Canonical name	Supersymmetry
Date of creation	2013-03-22 18:17:00
Last modified on	2013-03-22 18:17:00
Owner	bci1 (20947)
Last modified by	bci1 (20947)
Numerical id	22
Author	bci1 (20947)
Entry type	Definition
Classification	msc 55U40
Classification	msc 55-02
Classification	msc 81Q60
Classification	msc 81R50
Classification	msc 81R15
Synonym	extended quantum symmetry structures
Synonym	generalized double algebras
Synonym	supersymmetries
Related topic	QuantumAlgebraicTopology
Related topic	AlgebraicFoundationsOfQuantumAlgebraicTopology
Related topic	SuperfieldsSuperspace
Related topic	LieSuperalgebra3
Defines	extended quantum symmetry structures
Defines	both local and global