Propagator for matrix fields (based on Srednicki ch80, p490)

In summary, the conversation involves discussing the propagator for a matrix valued field with a relevant part of the Lagrangian being Tr(-\tfrac{1}{2}\partial^{\mu}B\partial_{\mu}B+..). The summary explains that the propagator for the matrix field can be seen by expanding the Lagrangian in terms of the coefficient field, which leads to the propagator of the coefficient field being \Delta^{ab}(k^2)=\tfrac{\delta^{ab}}{k^2-i\epsilon}. However, the summary also mentions that it is not clear how to see the propagator of the matrix field and asks for help. It is also mentioned that each external propagator
  • #1
LAHLH
409
1
Hi,

If I have a matrix valued field [itex] B(x)_i^{..j}=B^a (x) (T^a)_i^{..j} [/itex] and the relevant part of my Lagrangian is [itex]L=Tr(-\tfrac{1}{2}\partial^{\mu}B\partial_{\mu}B+..) [/itex] then how can I see that the propagator for the matrix field is [itex] \Delta_{i..k}^{..j..l}(k^2)=\tfrac{(T^a)_i^j(T^a)_k^l}{k^2-i\epsilon} [/itex] ?

I understand that if we expand the L in terms of the coefficent field we get [itex] L=-\tfrac{1}{2}\partial^{\mu}B^a\partial_{\mu}B^{a} [/itex] and this leads to the propagator for the coefficient field as [itex] \Delta^{ab}(k^2)=\tfrac{\delta^{ab}}{k^2-i\epsilon} [/itex], (just like usual for a massless scalar field) but not sure how to see the propagator of matrix field...

thanks for any help...
 
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  • #2
Also why exactly does each external propagator carry at [itex] T^{a_i} [/itex] factor?
 

1. What is a propagator for matrix fields?

A propagator for matrix fields is a mathematical function that describes the amplitude for a matrix field to propagate from one point to another in space and time. It is used in quantum field theory to calculate the probability of a particle being detected at a certain position and time, given its initial position and time.

2. What is the significance of the propagator for matrix fields in physics?

The propagator for matrix fields is an important concept in quantum field theory as it allows us to calculate the behavior and interactions of particles at the quantum level. It is used in various calculations, such as scattering amplitudes and Feynman diagrams, which help us understand the fundamental forces and particles of the universe.

3. How is the propagator for matrix fields calculated?

The propagator for matrix fields is calculated using the path integral method, which involves summing over all possible paths that a particle could take from its initial position to its final position. This requires the use of complex mathematical techniques and is often done using computer simulations.

4. What is the role of the propagator for matrix fields in quantum mechanics?

In quantum mechanics, the propagator for matrix fields is closely related to the Green's function, which describes the response of a system to an external force. It is used to calculate the time evolution of a quantum state and is essential in understanding the behavior of quantum systems.

5. Can the propagator for matrix fields be applied to other fields besides quantum mechanics?

Yes, the concept of a propagator can be applied to other fields besides quantum mechanics, such as classical mechanics and statistical mechanics. In these cases, the propagator describes the probability of a particle or system evolving from one state to another over a certain period of time. However, the specific form of the propagator will vary depending on the field and its governing equations.

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