Suggested reading for renormalization (not only in QFT)
However, the appearance of Renormalization in other fields of physics Renormalization Group approach in statistical physics etc.), where its necessity and effectiveness have, more or less, clear physical meaning, suggests a general concept beyond the mere "shut up and calculate" ad-hoc gadget it is served as in usual QFT courses.
A pedestrian explanation of Renormalization Groups - from QED …
So renormalization is an integral part of the QFT in the great contrast with classical theories. Other place where notion of renormalization group flow is important is condensed matter theory. This is because these flows have fixed points that (when they are non-trivial) correspond to critical points (this is again connected with the mentioned ...
Understanding renormalization conditions in the $\\phi^4-$theory
2017年5月28日 · The renormalization conditions in ϕ4 − theory are given in Eqn. 10.19 of Peskin and Schroeder, are supposed to define the physical mass and the physical couplings. The second condition is fine; calculating the diagram on the LHS, multiplying that by i and setting s = 4m2, t = u = 0, one can read off the physical coupling λ.
renormalization - What is "the scale at which a theory is defined ...
2016年3月7日 · In general, the renormalization constants are given as (for example, for dimensional regularization) Zi =ai +∑j=1 c(i) j ϵj, (0) (0) Z i = a i + ∑ j = 1 c j (i) ϵ j, We have the freedom for choosing ai a i, while c(i) j c j (i) are completely fixed by the structure of infinities in theory. The renormalization group states that the scheme ...
quantum field theory - Dirac once said that renormalization is just …
2017年12月19日 · It turns out that renormalization has a nice mathematical structure described by the cosmic Galois group: What is called the cosmic Galois group is a motivic Galois group that naturally acts on structures in renormalization in quantum field theory. The actual renormalization group is a 1-parameter subgroup of the cosmic Galois group.
Why do we need to renormalize in QFT, really?
2017年6月14日 · Though it was now obvious that QED was the correct theory to describe electromagnetic interactions, the renormalization procedure itself, allowing the extraction of finite results from initial infinite quantities, had remained a matter of some concern for theorists: the meaning of the renormalization ‘recipe’ and, thus, of the bare ...
general relativity - Why is quantum gravity non-renormalizable ...
2019年6月30日 · The reason why gravity is non renormalizable has to do with the mass dimension of the coupling. To be more precise one should say that the theory is not renormalizable by power counting. There are two ways to approach this, which, in my opinion, are equally important. Renormalization as a procedure to cure divergences.
Difference between regularization and renormalization?
Renormalization is the process by which you take the regularized theory, a theory written in terms of bare quantities and the regularization parameter $(\Lambda, m, \lambda, \dots)$, and you apply certain conditions (renormalization conditions) which cause physical quantities you want to compute, such as scattering amplitudes, to depend only on ...
Renormalization of phi cubed theory - Physics Stack Exchange
2017年7月6日 · ϕ3 theory in 4 dimensions is what is called a super-renormalizable theory. This means that as yourself pointed out that the superficial degrees of divergence decrease at higher orders. The reason that people rarely speak of it is that ϕ4 theory is arguably more interesting. A feature of super-renormalizable theories is that they are quite ...
Quantum Renormalisation Made Easy - Physics Forums
2015年5月9日 · In general, renormalization does produce an extra dimension which has the meaning of “energy”, but it has nothing to do with GR. In string theory, when the starting lattice has certain properties, renormalization is conjectured to produce a space that has exactly all the properties of string theory, which has GR as a low energy limit.