4.2.13. PairLift file

This file determines the values of PairLift couplings \(J_{ij}^{\rm PairLift}\) (for \(S=1/2\) system),

\[{\mathcal H}+=\sum_{i,j}J_{ij}^{\rm PairLift} (c_ {i \uparrow}^{\dagger}c_{i\downarrow}c_{j \uparrow}^{\dagger}c_{j \downarrow}+c_ {i \downarrow}^{\dagger}c_{i\uparrow}c_{j \downarrow}^{\dagger}c_{j \uparrow}).\]

An example of the file format is as follows.

======================
NPairLift 6
======================
========NPairLift ======
======================
   0     1  0.50000
   1     2  0.50000
   2     3  0.50000
   3     4  0.50000
   4     5  0.50000
   5     0  0.50000

File format

• Line 1: Header
• Line 2: [string01] [int01]
• Lines 3-5: Header
• Lines 6-: [int02] [int03] [double01] .

Parameters

• [string01]

  Type : String (a blank parameter is not allowed)

  Description : A keyword for the total number of PairLift couplings. You can freely give a name to the keyword.

• [int01]

  Type : Int (a blank parameter is not allowed)

  Description : An integer giving the total number of PairLift couplings.

• [int02], [int03]

  Type : Int (a blank parameter is not allowed)

  Description : An integer giving a site index (\(0<=\) [int02], [int03] \(<\) Nsite).

• [double01]

  Type : Double (a blank parameter is not allowed)

  Description : A value for \(J_{ij}^{\rm PairLift}\).

Use rules

• Headers cannot be omitted.
• A program is terminated when the components of the PairLift couplings are double counted.
• A program is terminated when [int01] is different from the total number of PairLift couplings defined in this file.
• A program is terminated when either [int02] or [int03] is outside the range of the defined values.