Tools /
## MpConstructConstruct finite or infinite product states by specifying the local basis states and bond quantum numbers. ## Synopsis
## Options
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`--lattice` Lattice filename [required]
`--output` Output wavefunction filename [required]
`--force` Force overwriting the output file
Create an infinite wavefunction [default behaviour]
Create a finite wavefunction
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## DescriptionThis tool will create a wavefunction which is written as a tensor product of the local basis states in the lattice file. The local basis states are specified in the positional argument of the tool. There are two ways to specify the state: - Only the local basis states are written, and are separated by colons, e.g.
`0:1:0:1` for a`bosehubbard-u1` lattice. This syntax is more suitable for lattices with Abelian symmetries, since then the quantum numbers at the bonds can be uniquely determined by the local basis states. - The local basis states and the bond quantum numbers are specified, where the quantum numbers are placed in brackets between the basis states, e.g.
`"(0.5)1(1.5)1(0.5)"` for a`spinchain-su2` lattice with`-S 1` (note that both the initial and final quantum numbers need to be specified). This syntax is more suitable for lattices with non-Abelian symmetries, since the bond quantum numbers are not uniquely determined, and need to be specified.
It is not possible to mix these two syntaxes (e.g. by having a colon on some bonds and having the quantum number in brackets on some other bonds). Whitespaces are ignored, so If the local basis state or quantum number can be uniquely determined (e.g. if there is only one local basis state, as in To generate an infinite state, the string will specify the unit cell of the resulting wavefunction. For finite states, the string will specify the entire wavefunction. Note that in both cases, the number of sites in the string must be an integer multiple of the lattice unit cell (so if the lattice has a four-site unit cell, we must write either 4, 8, 12 etc. states for the infinite unit cell or finite wavefunction). ## Examples- To generate an infinite NĂ©el state, we can use
$ spinchain-u1 -o lattice $ mp-construct -l lattice -o psi 0.5:-0.5 Note that if we want to have the unit cell the other way around, we must use $ mp-construct -l lattice -o psi " -0.5:0.5" so the program doesn't interpret If we want a finite state, we must write out how many sites we want: e.g. for a 10-site state $ mp-construct -l lattice -o psi --finite 0.5:-0.5:0.5:-0.5:0.5:-0.5:0.5:-0.5:0.5:-0.5 - To generate the AKLT state, we can use
$ spinchain-su2 -o lattice $ mp-construct -l lattice -o psi "(0.5)(0.5)" Since the only local basis state is |

Page last modified on December 13, 2022, at 02:05 AM