# Transport input documentation

Compose a System to calculate from its pieces. Each piece could be provided as an object or a dictionary of parameters suitable for initializing that object.

Used to initialize class `qimpy.transport.Transport`

.

## YAML template:

ab-initio: # Ab-initio material: file: [string] # Name of HDF5 file to load materials data from. T: [float] # Temperature. mu: 0.0 # Chemical potential in equilbrium. rotation: null # 3 x 3 rotation matrix from material to simulation frame. orbital-zeeman: null # Whether to include L matrix elements in Zeeman coupling. observable-names: n # Control which observables will be output. relaxation-time: # Relaxation-time approximation to scattering: tau-p: inf # Momentum relaxation time. tau-s: inf # Spin relaxation time. tau-e: inf # Conduction bands relaxation time. tau-h: inf # Valance bands relaxation time. tau-eh: inf # Relaxation time of conduction-valance off diagonal terms. max-dmu: 0.001 # Maximum mu change in Newton-Rhapson method. tau-recomb: inf # Recombination time. nv: 0 # Number of valance bands. eps: 1e-12 # Precision in the determination of mu_e and mu_h. only-diagonal: yes # Whether only diagonal terms change. lindblad: # Ab-initio lindblad scattering: scale-factor: 1.0 # Overall scale factor for scattering rate. light: # Light-matter interaction (coherent / Lindblad): coherent: yes # Switch between coherent and Lindbladian implementations. gauge: velocity # Switch between 'velocity' or 'length' gauge. A0: null # Vector potential amplitude. E0: null # Electric-field amplitude. omega: 0.0 # Angular frequency / photon energy of the light. t0: 0.0 # Center of Gaussian pulse, used only if sigma is non-zero. sigma: 0.0 # Time width of Gaussian pulse, if non-zero. smearing: 0.001 # Width of Gaussian function to represent delta function. pulseB: # Magnetic field pulses: B0: (0.0, 0.0, 0.0) # Magnetic field amplitude vector. g: 0.0 # Gyromagnetic ratio magnitude to calculate mean Larmor frequency. g-flip: 0.0 # Gyromagnetic ratio magnitude to calculate flip time. t-starts: (0.0,) # Start times of oscillating magnetic field pulse. angles: (3.141592653589793,) # Corresponding target spin rotation angles (in radians). fermi-circle: # Fermi-circle material for graphene/2DEG: kF: [float] # Fermi wave vector in atomic units. vF: [float] # Fermi velocity in atomic units. N-theta: [int] # Number of k along Fermi circle. theta0: 0.0 # Angle of first k-point. patch-set: # Geometry consisting of bicubic patches: svg-file: [string] # Path to an SVG file containing the input geometry svg-unit: 1.0 # Real length corresponding to one unit of distance in SVG. grid-spacing: [float] # Maximum spacing between grid points anywhere in the geometry. contacts: [string or dict] # Dictionary of contact names to parameters. grid-size-max: 0 # Maximum grid points per dimension after quad subdvision. save-rho: no # Whether to write the full density matrices to the checkpoint file. parameter-grid: # Virtual geometry of disconnected points for batched dynamics: shape: [int] # Dimensions of parameter grid (always 2D). dimension1: null # Parameter names and values to sweep along dimension 1. dimension2: null # Parameter names and values to sweep along dimension 2. save-rho: no # Whether to write the full density matrices to the checkpoint file. checkpoint: null # Checkpoint file to read at start-up. checkpoint-out: null # Checkpoint file pattern to write at regular intervals.

## Component classes:

## Parameters:

### ab-initio

*Type:* AbInitio, *Default:* null

Ab-initio material. Exactly one supported material type must be specified.

### fermi-circle

*Type:* FermiCircle, *Default:* null

Fermi-circle material for graphene/2DEG. Exactly one supported material type must be specified.

### patch-set

*Type:* PatchSet, *Default:* null

Geometry consisting of bicubic patches. Exactly one supported geometry type must be specified.

### parameter-grid

*Type:* ParameterGrid, *Default:* null

Virtual geometry of disconnected points for batched dynamics. Exactly one supported geometry type must be specified.

### checkpoint

*Type:* string or null, *Default:* null

Checkpoint file to read at start-up.

### checkpoint-out

*Type:* string or null, *Default:* null

Checkpoint file pattern to write at regular intervals. The pattern should contain an integer format eg. ‘{:04d}’ that can be replaced with the frame number.