5 ms·
Having done some QFT, now doing hydrodynamics, I never knew that lattice people use a staggered grid for the fermions and gluons. Do you know if it's for the sa
by semi-extrinsic 10y ago
Having done some QFT, now doing hydrodynamics, I never knew that lattice people use a staggered grid for the fermions and gluons. Do you know if it's for the same reason as staggering velocity and pressure in CFD; to avoid checkerboarding of the spinors (pressure)?
- KenoFischer 10y agoIf I remember correctly, there is no way to obtain a gauge invariant discretization if you try to put the gluons at the lattice sites. I can try to find a proper reference.
- evanb 10y agoKenoFischer is right---it comes down to gauge invariance. Gauge symmetry is a local symmetry that dictates a lot of the structure of QCD. If your discretization breaks it (and say, only recovers it in the continuum limit) you will have very bad renormalization and fine-tuning problems. Putting the gauge on the links automatically guarantees that gauge symmetry is respected, even at the discretized level, and jibes very well with the fact that the gauge field / gauge connection describes, in some way, how to perform parallel transport. So, it's very natural for the gauge to connect the sites together in that you need to know the value of the link in order to compare quantities on two adjacent spacetime sites. https://en.wikipedia.org/wiki/Gauge_theory https://en.wikipedia.org/wiki/Gauge_theory https://en.wikipedia.org/wiki/Connection_form https://en.wikipedia.org/wiki/Connection_form https://en.wikipedia.org/wiki/Parallel_transport https://en.wikipedia.org/wiki/Parallel_transport