Renormalized vertex functions in terms of bare ones

  • #1
Siupa
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Let ##\Gamma[\varphi] = \Gamma_0[\sqrt{Z}\varphi ] = \Gamma_0[\varphi_0]## be the generating functional for proper vertex functions for a massless ##\phi##-##4## theory. The ##0## subscripts refer to bare quantities, while the quantities without are renormalized. Then
$$\tilde{\Gamma}^{(n)}(p_i, \mu, \lambda) = Z^{\frac{n}{2}}\left( \tfrac{\Lambda}{\mu}, \lambda\right) \tilde{\Gamma}_0^{(n)}(p_i, \Lambda, \lambda_0)$$
Where the ##\tilde{\Gamma}^{(n)}## are the ##n##-point proper vertex functions in Fourier space (bare and renormalized), ##\Lambda## is the Pauli-Villars cutoff, ##\mu## an arbitrary scale, ##p_i## external momenta, ##\lambda## the ##\phi##-##4## couplings (bare and renormalized). How does one show this?
 

1. What is the concept of renormalization in terms of vertex functions?

Renormalization is a mathematical technique used in theoretical physics to remove divergences that arise in perturbation theory calculations. In terms of vertex functions, it involves redefining the bare vertex function in terms of a renormalized one, which takes into account the effects of virtual particles.

2. How are renormalized vertex functions related to bare ones?

Renormalized vertex functions are related to bare ones through a mathematical transformation known as the renormalization group equation. This equation allows us to calculate the renormalized vertex function from the bare one, taking into account the effects of virtual particles.

3. What is the significance of renormalized vertex functions in quantum field theory?

Renormalized vertex functions play a critical role in quantum field theory as they allow us to make predictions about the behavior of particles and their interactions. By accounting for the effects of virtual particles, renormalized vertex functions provide a more accurate description of the physical world.

4. How do renormalized vertex functions affect the calculation of physical observables?

Renormalized vertex functions have a direct impact on the calculation of physical observables in quantum field theory. By accounting for the effects of virtual particles, they help to remove divergences and provide more accurate predictions for physical quantities such as cross-sections and decay rates.

5. Can renormalized vertex functions be calculated exactly?

No, renormalized vertex functions cannot be calculated exactly as they depend on the energy scale of the interaction and the specific theory being studied. However, they can be calculated to high precision using mathematical techniques such as perturbation theory and the renormalization group equation.

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