Tagged Questions
0
votes
0answers
187 views
How is the term “Born level” usually defined?
How is the term "Born level" usually defined, e.g. in talking about the $pp\to Z/\gamma^*\to e^+e^-$ cross section at Born level?
1
vote
1answer
78 views
Two definitions: 'semi-classical space-time' and 'supersymmetric Minkowski space'
By reading articles I ran several times into two terms, never being defined so I assume they must have well established definitions somewhere.
The first is semi-classical space-time. If I where to ...
3
votes
2answers
654 views
What is a non linear $\sigma$ model?
What exactly is a non linear $\sigma$ model? In many books one can view many different types of non linear $\sigma$ models but I don't understand what is the link between all of them and why it is ...
6
votes
1answer
497 views
What is a general definition of the spin of a particle?
In quantum field theory, one defines a particle as a unitary irreducible representations of the Poincaré group. The study of these representations allows to define the mass and the spin of the ...
1
vote
1answer
96 views
Reality constraint
What is the "definition" of a reality constraint and why is it called that way?
(I mean how it is used for example in quantum field theory and string theory)
0
votes
1answer
212 views
Mathematical definition of Bogomol'nyi–Prasad–Sommerfield (BPS) states
What is the mathematical definition of Bogomol'nyi–Prasad–Sommerfield (BPS) states, independent of any specific physical theory.
