Gauge and Lorentz invariance for Lagrangians

In summary, the given Lagrangian involves terms with column vectors H and L, which could refer to SU(2) doublets or spinors. These terms involve multiplication of components of the vectors and neutral Majorana fermions N1 and N1c. A reference for this expression would be helpful in understanding the context of this Lagrangian.
  • #1
spaghetti3451
1,344
33
Consider the following Lagrangian:

##YHLN_{1}^{c} + Y^{c}H^{\dagger}L^{c}N_{1} + \text {h.c.},##

where ##L=(N_{0}, E')## and ##L^{c} = (E^{'c}, N_{0}^{c})## are a pair of ##SU (2)## doublets and ##N_{1}## and ##N_{1}^{c}## are a pair of neutral Majorana fermions.

------------------------------------------------------------------------------------------------------------------------------------------------

1. In the first term, ##H## and ##L## are column vectors. How do you multiply two column vectors in the first term of the Lagrangian?

2. Are ##L## and ##L^{c}## ##4##-component spinors? Are ##N_{1}## and ##N_{1}^{c}## also ##4##-component spinors? How do the components of the vectors and spinors in the first term multiply?
 
Last edited:
Physics news on Phys.org
  • #2
spaghetti3451 said:
Consider the following Lagrangian:

##YHLN_{1}^{c} + Y^{c}H^{\dagger}L^{c}N_{1} + \text {h.c.},##

where ##L=(N_{0}, E')## and ##L^{c} = (E^{'c}, N_{0}^{c})## are a pair of ##SU (2)## doublets and ##N_{1}## and ##N_{1}^{c}## are a pair of neutral Majorana fermions.

------------------------------------------------------------------------------------------------------------------------------------------------

1. In the first term, ##H## and ##L## are column vectors. How do you multiply two column vectors in the first term of the Lagrangian?

2. Are ##L## and ##L^{c}## ##4##-component spinors? Are ##N_{1}## and ##N_{1}^{c}## also ##4##-component spinors? How do the components of the vectors and spinors in the first term multiply?
Can you give a reference for this expression? Is it a supersymmetric system? I am not sure what you mean by "H and L are column vectors", it could mean SU(2) doublets or it could mean spinors. In either case, there is something that is not working so the original reference would be helpful.
 

1. What is gauge invariance?

Gauge invariance refers to the property of a physical theory or system to remain unchanged under a transformation of its underlying mathematical description. In other words, the equations and laws that govern the system do not change when certain mathematical quantities, known as gauge transformations, are altered.

2. How is gauge invariance related to Lagrangians?

Gauge invariance is closely related to Lagrangians, which are mathematical functions used to describe the dynamics of a system. Lagrangians that are invariant under gauge transformations are said to have gauge invariance, which is a desirable property in many physical theories.

3. What is Lorentz invariance?

Lorentz invariance is the property of a physical theory or system to remain unchanged under a transformation of its coordinate system. This means that the laws and equations that govern the system do not change when the coordinates used to describe it are rotated, translated, or boosted.

4. How is Lorentz invariance related to Lagrangians?

Lorentz invariance is also closely related to Lagrangians. In fact, many physical theories, such as special relativity and quantum field theory, are built upon the principle of Lorentz invariance. Lagrangians that are invariant under Lorentz transformations are said to have Lorentz invariance.

5. Why are gauge and Lorentz invariance important in physics?

Gauge and Lorentz invariance are important principles in physics because they allow us to describe and understand the fundamental laws and dynamics of the universe. They provide a consistent framework for describing physical phenomena and have been successfully applied in a wide range of fields, including classical mechanics, electromagnetism, and quantum mechanics.

Similar threads

  • High Energy, Nuclear, Particle Physics
Replies
11
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
2
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
4
Views
1K
  • Special and General Relativity
Replies
9
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
1K
Replies
3
Views
614
  • High Energy, Nuclear, Particle Physics
Replies
3
Views
1K
  • High Energy, Nuclear, Particle Physics
2
Replies
38
Views
3K
  • Special and General Relativity
Replies
1
Views
774
Back
Top