Parameter: nflip

Definition

Flip period for spin up and spin down states.

Type

Integer

Default value

20000

Component

ALL, except for the DAISY component.

Behavior

Care must be taken to prevent the system from being trapped in a state which breaks a symmetry of local Hamiltonian when it should not be. To avoid un-physical trapping, we introduce "flip" moves, which exchange the operators corresponding, for example, to up and down spins in a given band.

In this code, nowadays the following flip schemes are supported:

• cflip = 1, flip inter-orbital spins randomly,

• cflip = 2, flip intra-orbital spins one by one,

• cflip = 3, flip intra-orbital spins globally.

Here cflip is an internal variable, instead of an input parameters, you can not setup it in the solver.ctqmc.in file.

So the question is: how to control cflip via the nflip parameter?

Now we use the sign of nflip to control flip schemes

• nflip = 0, means infinite long period to do flip

• nflip > 0, combine cflip = 2 (80%) and cflip = 3 (20%)

• nflip < 0, combine cflip = 1 (80%) and cflip = 3 (20%)

Comment

If nflip /= 0, the absolute value of nflip is the flip period.