spin system creation¶

In Spin-Scenario, a spin system can be easily created with a Lua table, including all necessary parameters such as spin, zeeman, jcoupling and relaxation. For example, the 13C labelled alanine can be formed with following code snippet:

local sys = spin_system{
spin = "13C 13C 13C",
zeeman = "1 scalar 15.74 kHz 3 scalar  -4.3 kHz",
jcoupling ="1 2 scalar 54.2 Hz 2 3 scalar 35.4 Hz"
}

operator and state¶

In general, the density operators or state operators can be represented as products of individual spin operators. The op and state functions are used for representing the density operator and the state operator respectively. The validated strings for each spin are

• I+
• I-
• Iz
• Ie

E.g. a state I1pI3m can be defined as

sys:state{1, "I+", 3, "I-"}

Moreover, taking advantage of the computer algebra system YACAS, Spin-Scenario also provides a very practical feature for the construction of more complex operators by expr_state that are a linear combination of arbitrary either spherical or cartesian operators. E.g.

sys:expr_state("2*I1xI3x-0.5*I2xI3y")

is a straightforward generation of the combined state 2I1xI3x-0.5I2xI3y. The Yacas integration was fully utilized throughout Spin-Scenario to offer a nature manner for kinds of expression evaluation.

For a specific spin system, it is also possible to retrieve its free Hamiltonian, total Hamiltonian and the relaxation superoperator via sys.L0, sys.L and sys.R respectively.