Questions tagged [superspace-formalism]
The Green-Schwarz formalism, or the superspace-formalism, are formalisms for supersymmetry with explicit spacetime supersymmetry.
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Relation between the on-shell superspace and lightcone superspace
There is an on-shell superspace (introduced by V.Nair) for $\mathcal{N} = 4$.
It is introduced in the section 4.3 in this paper https://arxiv.org/abs/1308.1697 , for instance.
Four Grassmann
variables ...
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1answer
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How do I prove that the product of chiral superfields is itself a chiral superfield?
I am currently learning about $\mathcal{N}=(2,2)$ supersymmetry and have come up against what is probably a really silly question.
The $\mathcal{}N=(2,2)$ superspace consists of bosonic coordinates $x^...
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Rewriting an expression into a manifestly supersymmetric form
In $\mathcal{N}=2$ supersymmetry, one can define the following superderivatives
\begin{equation}
D_{\theta}=\partial_{\theta}+\frac{1}{2}\bar{\theta}\partial_{u}, \hspace{4mm} D_{\bar{\theta}}=\...
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1answer
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Invariant of supersymmetry?
Given two vectors in 3D superspace $(x_1^\mu,\theta_1^\alpha,\overline{\theta}_1^\alpha)$ and $(x_2^\mu,\theta_2^\alpha,\overline{\theta}_2^\alpha)$ I am trying to find a polynomial invariant under ...
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Extended SUSY and superspace
I am trying to understand how to construct an action using the superspace formalism for $\mathcal N>1$. I have read that this is quite difficult to do, so let's consider a simple example. Suppose I ...
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Auxiliary fields in non-supersymmetric theory
It is well-known, that in superspace formulation of supersymmetric theories auxiliary fields appear. In present of such fields SUSY transformations are linear and independent of model.
Are some non-...
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1answer
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What is the form of local supersymmetry transformations in superspace?
So the most general local superspace transformation generator I can write is:
$$\hat{L} = A^\mu(x,\theta)\frac{\partial}{\partial x^\mu} + B^\alpha(x,\theta)\frac{\partial}{\partial \theta^\alpha}$$
...
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1answer
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Gauge invariant supersymmetric transformations
Given the following action
$$
\mathcal{S}=\int{d^4x\;d^2\theta\;d^2\bar{\theta}\left(\bar{Q}_+e^{2V}Q_++\bar{Q}_-e^{-2V}Q_--2\xi V\right)}+\int{d^4x\;d^2\theta\left(mQ_-Q_++\frac{\tau}{16\pi i}W^\...
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1answer
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SUGRA & consistent field theories
Why must a consistent theory with a rarita schwinger field (i.e. massless gravitino in the spectrum) be supersymmetric? I was reviewing the GSO projection, Spin Structure, etc. & wasn’t able to ...
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1answer
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General expression for a Scalar Superfield with ${\cal N = 1}$ in $D = 10$
I need to write explicitly the most general form of a scalar superfield in 10 dimensions up to second order in grassman variables $\theta^\alpha$. I know that up to first order one can write
\begin{...
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1answer
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Expand superspace function into component form
In 2D (1,1) superconformal field theory, the invariant "distance" between two points $Z_1=(z_1,\theta_1)$ and $Z_1=(z_1,\theta_1)$ in superspace is $$Z_{12}=z_1-z_2-\theta_1\theta_2.$$
My question ...
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1answer
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Expanding superfields: inconsistency of notation?
If I have a wavefunction of a fermion field $\Psi[\psi]$ I can expand it like so about some vacuum:
$$\Psi[\psi] = \Psi_0[\psi]( a + \int a(x)\psi(x)dx+\int a(x,y)\psi(x)\psi(y)dxdy+...)$$
Now all ...
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Determination of Torsion constraints in ${\cal N} = 1$, D = 10 Superspace
For the on-shell theory, containing the graviton $e_m^{\ \ \ a}$, gravitino $\psi_m^{\ \ \ \alpha}$, dilaton $\phi$, dilatino $\lambda$ and 3-form $H_{n m p}$, one has to demand that the SUSY algebra ...
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1answer
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Why is an action built from superfields guaranteed to be supersymmetric?
Given a superfield (in 0+1 spacetime + 2 superspace coordinates)
$$X(t,\theta_1,\theta_2) = x(t) + \theta_i \psi_i(t) + \theta_1 \theta_2 F_{12}(t)\tag{1}$$
and given the standard supercharges ...
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Supersymmetry Generator Definition for ${\cal N }= 1$
I am studying SYM $\mathcal{N}$ = 1 in D = 10, and using the bimodular representations for the 32x32 gamma matrices $\Gamma^a$. This means that I work with the off-diagonal 16x16 matrices, which I ...
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1answer
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Anti-Commutator of derivatives of Grassmann variables
How do I evaluate the anti-commutator of $\frac{\partial}{\partial\chi}$ and $\frac{\partial}{\partial\eta}$ when both $\chi$ and $\eta$ are Grassmann variables?
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1answer
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What are Grassmann numbers in field theory?
I've been struggling with the use of Grassmann numbers in QFT e.g. Peskin and Schroeder. They are introduced as "numbers" whose product is antisymmetric, and associative (this isn't said, but used in ...
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1answer
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${\cal N} = 1$ SUSY Non-renormalization theorem
In Ref. 1, on Page 53, the ${\cal N} = 1$ SUSY non-renormalization theorem is derived. One first specifies the symmetries of the general ${\cal N} = 1$ SUSY action in the superspace formalism, and ...
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1answer
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Auxiliary Grassmann variables in supergeometry
I was reading on super geometry and how it is used to model fermions and supersymmetry in classical field theory.
In texts like [1] or [2] the authors introduced auxiliary Grassmann odd variables to ...
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1answer
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Grassmann-odd extra dimensions and gravity
Take a world with $D=3+n$ space-time dimensions, where $n$ are extra space-like dimensions.
With extra-dimensional newton gravity
$$F=G_N(D)\dfrac{Mm}{r^{2+n}}$$
Can $n$ affect IF the extra ...
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1answer
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Could you get real space from Grassmann numbers?
You can get a vector field from a pair of spinor fields with $A_\mu(x)=\psi(x) \gamma_\mu \overline{\psi}(x)$. Using this fact could you define a space-time vector in terms of Grasman numbers?
Say ...
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Super-gauge transformation in two dimensional $\mathcal{N}= (0,2)$ superspace
I'm trying to couple matter to $\mathcal{N}=(0,2)$ SYM in 2d using superfield formalism. There are some paper (this on Sec. 6, or this on Sec. 3 [whose notation will be used here]) that construct what ...
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1answer
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2D ${\cal N}=(2,2)$ Super Yang-Mills with Superspace
I'm reading this famous paper by Witten. There is the expression of field strength for the abelian vector multiplet (eq. (2.16)):
$$\Sigma = \frac{1}{\sqrt{2}}\bar{D}_+D_- V\;.\tag{2.16}$$
I'm ...
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1answer
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Are there SUSY Lagrangian terms that are not D-term nor F-term?
I've read that a way to construct supersymmetric invariant lagrangian could be either to integrate a superfield in the whole superspace, i.e. in all anticommuting coordinates (D-term), or in half of ...
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1answer
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Supergravity action as a total integral, over 4 spacetime and 4 Grassmann coordinates
Wess and Bagger, in their Supersymmetry and Supergravity, give the action for a global SUSY, ${\cal N}=1$, $D=4$, Yang-Mills gauge model as an integral over the 4 spacetime coordinates and 4 Grassmann ...
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1answer
107 views
Super Field Strength Identity
I work on a introduction into Super-symmetry. In the course we define
\begin{equation}
D_{\alpha} = \frac{\partial}{\partial \theta^{\alpha}} - i \sigma^{\mu}_{\alpha \dot{\alpha}} \bar{\theta}^{\dot{\...
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1answer
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Ambiguity of Time Derivative of Superfunctions
I think that there is an ambiguity for defining the time derivative of a superfunction on the phase space of pseudo-classical mechanics of Grassmann numbers.
Let $\xi$ be a Grassmann odd number. Its ...
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1answer
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Questions about the Ferrara-Zumino Multiplet
These questions arose while reading the paper ``Comments on Supercurrent Multiplets, Supersymmetric Field Theories and Supergravity" by Komargodski and Seiberg (arXiv:1002.2228)
The Ferrara-Zumino ...
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3answers
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What is the definition of $\delta^{m|n}$ and $\delta^{m}$?
I am reading the paper. What is the definition of $\delta^{m|m}$ and $\delta^{m+k}$ in (1.1) and (1.3) on pages 2,3? Are they some kind of delta function?
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3answers
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Grassmann numbers & supermanifolds
I'm asking this question because I'm currently trying to learn about Super Symmetry but I'm having trouble understanding the concept of super-space and super-manifold.
I read that in super-spaces you ...
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1answer
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Should the complex conjugate of a derivative of a Grassmann number include a sign?
Take a real Grassmann variable, by which I mean $\theta=\theta^*$. We have
$$\int d\theta~ \theta =1,\qquad \frac{\partial}{\partial\theta}\theta=1$$
If I define the conjugation of Grassmann ...
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1answer
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Fayet-Iliopoulos terms
It is mentioned in first page of this paper by Seiberg and Komargodski that the Lagrangian in superspace of a $U(1)$ gauge SUSY theory with FI terms is not gauge invariant. However, the FI terms in ...
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1answer
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State counting in the d = 1+2, $\cal{N} = 2$ vector multiplet
The question is from Box 8.2, page 282 of the book "Gauge Gravity Duality" by Ammon and Erdmenger. The link to the specific page from Google Books is here.
According to the authors, a $\mathcal{N} = ...
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Projective superspace: why extra bosonic coordinates
I'm studying the projective superspace formalism for N = 4 supersymmetric $\sigma$-models in two dimensions. My question is: why do we need the extra bosonic coordinates for the manifest action?
I ...
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2answers
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Do the Grassmann coordinates in the superfield formalism have any physical meaning?
In the superfield formalism we consider fields in a space who has four so called bosonic coordinates $x^{\nu}$ and four so called fermionic coordinates $\theta_1$,$\theta_2$,$\bar{\theta_1}$,$\bar{\...
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0answers
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What mathematical structure describes superspace and superfields?
In every book related to supersymmetry I have encountered at some point the idea of superspace is introduced. Superspace is presented as a space spanned by 4 "normal" directions and 4 Grassmannian ...
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1answer
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Why is the mass dimension of anticommutingcoordinates $[Mass]−1/2$
I am reading a review about supersymmetry and in page 29 I have read that the mass dimension of the Grassmann anticommuting coordinates is $-1/2$. Why this? why don't they have the same mass ...
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1answer
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Basic question about superspace, Grassmann numbers and world sheet supersymmetry
So, I'm trying to read the section on superspace from the book on string theory by Becker, Becker and Schwarz, and I realized that I've been stuck on something simple for a while. Some relevant ...
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1answer
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Supersymmetry transformations as coordinate transformations
Usually, a supersymmetry transformation is carried out on bosonic and fermionic fields which are functions of the coordinates (or on a superfield which is a function of real and fermionic coordinates)....
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1answer
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${\cal N}=4$ SYM in terms of ${\cal N}=1$: The $SO(6)$ in the Yukawa term
I'm trying to write ${\cal N}=4$ SYM in terms of ${\cal N}=1$ superfields. I have the Lagrangian
$$\mathcal{L}=\frac{1}{16 k} \int d^2 \sigma \text{Tr} \big[W^a W_a\big]+c.c+\int d^4\theta \text{Tr}\...
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0answers
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Information about fields and superfields [closed]
I want some explanation of fields and superfields (types and components), and what the relationship between them and representation of a group.
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Pre-gauge-fixed superspace action of the RNS superstring
When writing down the the action of the RNS superstring in superspace, all of the sources I have checked (BBS, GSW, Polchinski) seem to just write down the action in conformal gauge, that is
$$
S_{\...
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1answer
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Relation between $\mathcal{N}=2$ d=4 SUSY and $\mathcal{N}=4$ d=3 SUSY
What is meant with the fact that supersymmetry with $\mathcal{N}=4$ in three (2+1) dimensions is equivalent to supersymmetry with $\mathcal{N}=2$ in ordinary four (3+1) dimensions?
Which way does one ...
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1answer
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Are there two types of D-term and two types of F-term in SUSY?
I've noticed that one can obtain D-terms either by integrating a vector superfield (the vector multiplet) over superspace or by integrating a Kahler potential over superspace. In both cases we get ...
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Do commutation relations exist between superfields?
To quantize a theory, Klein gordon field for example, commutation relations are stablished. Or anticommuting ones in the fermionic case.
If I have the Wess.Zumino model or the free model:
$$S~=~\int\...
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2answers
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What is kappa symmetry?
On page 180 David McMohan explains that to obtain a (spacetime) supersymmetric action for a GS superstring one has to add to the bosonic part
$$
S_B = -\frac{1}{2\pi}\int d^2 \sigma \sqrt{h}h^{\alpha\...
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0answers
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Can mass dimension of a field be viewed as another 'quantum number'?
While studying SUSY in 4D, I noticed the dynamical chiral superfield has dimension [GeV], whereas the dynamical vector superfield (for gauge theories) is unitless. Because I was introduced to the ...
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Grassmann paradox weirdness
I'm running into an annoying problem I am unable to resolve, although a friend has given me some guidance as to how the resolution might come about. Hopefully someone on here knows the answer.
It is ...
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2answers
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Kähler potential vs full effective potential
In evaluating the vacuum structure of quantum field theories you need to find the minima of the effective potential including perturbative and nonperturbative corrections where possible.
In ...
