Matrix Product Toolkit | Tools / MpCorrelation

This tool calculates the correlation function of an operator.

Matrix Product Toolkit version HEAD-0.7.4.0 (subversion tree rev 802)
Compiled on Dec 10 2007 at 11:45:14
usage: mp-correlation <lattice> <psi1> <operator1> <first> <operator2> <last> [<psi2>]

The operator1 and operator2 must be defined in the lattice file. If the operators are only defined on some of the lattice sites, this doesn't matter; missing values will just be skipped.

This uses the site labelling defined in the lattice. To work properly, it must be a 1-dimensional lattice with numeric labels. The operators can be anything, there is no restriction that they must act only on a single site.

This program isn't particularly efficient. It is essentially equivalent to running mp-expectation in a loop, and does one complete sweep per data point. MpLocalCorrelation is much more efficient, but requires that the operators really are local and hence is not suitable for calculating multi-point correlators.

Examples

For example, if you wish to calculate the chirality correlator for a wavefunction, your command might look like:

 
for i in `seq 1 40`;
do mp-correlation lattice gs "Kappa" 1 "Kappa" $i >> gs.correlation
done;

This would give you a file with entries

i j <kappa(i) * kappa(j)> 0

which can be easily handled with matlab.

MpCorrelation

Examples

See also