Quantum Field Theory (QFT) is the theoretical framework describing the quantisation of classical fields which allows a Lorentz-invariant formulation of quantum mechanics. QFT is used both in high energy physics as well as condensed matter physics and closely related to statistical field theory. Use ...
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7 views
vortex in D dimensions solition
let us consider
the two-dimensional configuration shown in Fig. 3.1a. The lengths of the arrows
represent the magnitude of φ, while their directions indicate the orientation in
the $φ_1 -φ_2$ plane. ...
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0answers
40 views
gauge field in two dimensions
I dont understand this line
In two space dimensions finite energy solitions may exist if there is
also a gauge field
I got it from Lewis H.Ryder (page 435) (Quantum Field theory)
Can someone ...
2
votes
1answer
64 views
sine-Gordon equation
I have derived a solition equation (2 dimensions) from scalar field theory $$\varphi(x) = v\tanh\Bigl(\tfrac{1}{2}m(x - x_0)\Bigr),\tag{1}$$
and also I have got sine-Gordon equation for solition
...
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0answers
33 views
Domain wall and kink solutions from solitions equations
A general solition equation can be obtaion from scalar field theory $$\varphi(x) = v\tanh\Bigl(\tfrac{1}{2}m(x - x_0)\Bigr),\tag{92.6}$$
where $x_0$ is a constant of integration when we drived this ...
2
votes
0answers
16 views
Determinant for a coupled fluctuation Lagrangian
Lets consider a bosonic physical system in variables $t, x$ and $y(x)$ ($x$ dependent) with a classical Lagrangian $L$. To first order in fluctuations $x \to x+\xi_1$ and $y \to y+\xi_2$ the ...
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votes
3answers
137 views
Trace and adjoint representation of $SU(N)$
In the adjoint representation of $SU(N)$, the generators $t^a_G$ are chosen as
$$ (t^a_G)_{bc}=-if^{abc} $$
The following identity can be found in Taizo Muta's book "Foundations of Quantum ...
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votes
0answers
34 views
Supersymmetry and R-symmetry
R-symmetry for $N$ supercharges is $U(N)$. Is it possible to generalize R-symmetry (let's take $U(4)$) to be something like $U(2,2)$ (maybe analogous to Wick rotation of $SO(3,1)$ to $SO(4)$ ?) ?
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55 views
How does this paper relate to standard QED?
This paper proposes a microscopic mechanism for generating the values of $c, \epsilon_0, \mu_0$. They state that their vacuum is assumed to contain ephemeral (meaning existing within the limits of ...
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vote
0answers
45 views
Infinite Energy of Point Charges
As far as I know, in the context of classical and quantum physics, there isn't any (generally accepted satisfactory) explanation for infinite energy of a point charge. My question is:
What does it ...
4
votes
1answer
56 views
Significance of Poles of Correlation Function in QFT
In QFT, specifically in scattering processes, what is the physical significance of the poles / residues of the $N$-point correlation function? And why?
2
votes
1answer
54 views
Questions about angular momentum and 3-dimensional(3D) space?
Q1: As we know, in classical mechanics(CM), according to Noether's theorem, there is always one conserved quantity corresponding to one particular symmetry. Now consider a classical system in a $n$ ...
1
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0answers
28 views
QFT basics for Klein-Gordon fields
I am teaching myself QFT from Peskin for next years maths course and I have two questions:
What is a c-number? Is it a complex number, and if so why does it mean, ...
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vote
0answers
41 views
Helicity for Zero Rest Mass Field Equations
I'm trying to reconcile the usual definition of the helicity operator, namely
$$ h = \hat{p}.S$$
with the definition of a massless helicity $n$ field as a symmetric spinor field $\phi^{A\dots B}$ ...
0
votes
1answer
85 views
is really an atom stable?
Half filled and fulfilled atomic orbitals are stable because of :
high exchange energy.
The problem is with exchange energy. We have learnt that the half and fulfilled orbitals have maximum no. of ...
1
vote
0answers
95 views
+50
Field content and symmetry groups of Minimal Composite Higgs Models
I'm trying to teach myself the Composite Higgs Model, both its theory and its LHC phenomenology (particularly the 4DCHM). Unfortunately, I'm struggling; the literature is contradictory and/or omits ...
