Parameter Files Reference

PulseSuite simulations are configured entirely through plain-text parameter files. Each file controls a different aspect of the physics, and all are read at initialization time by InitializeSBE. No code changes are needed to switch between simulation regimes — just edit the parameter files.

File Overview

File	Controls
qw.params	Quantum wire material properties and dephasing rates
mb.params	Many-body physics flags (which interactions are active)
pulse.params	Optical pulse shape, wavelength, and timing
space.params	Spatial grid dimensions and resolution
qwarray.params	Quantum wire array geometry
pstd_abc.params	Absorbing boundary conditions for the PSTD grid

All parameter files use the same format: one value per line, with inline comments after #. The order of lines is fixed and must be preserved.

---

qw.params — Quantum Wire Properties

Defines the material and dephasing parameters for the quantum wire system. These map directly to the physical constants used in the Semiconductor Bloch Equations.

Line	Parameter	Units	Description
1	L	m	Length of quantum wire
2	Delta0	m	Z-thickness of quantum wire
3	gap	eV	Band gap energy
4	me	m_e0	Electron effective mass
5	mh	m_e0	Hole effective mass
6	HO	eV	Energy level separation
7	gam_e	Hz	Electron dephasing rate (1/lifetime)
8	gam_h	Hz	Hole dephasing rate
9	gam_eh	Hz	Interband dephasing rate
10	epsr	—	Background dielectric constant
11	Oph	eV	LO phonon energy
12	Gph	eV	Phonon damping (inverse lifetime)
13	Edc	V/m	Background DC electric field
14	jmax	steps	Write output every N time steps
15	ntmax	steps	Backup/checkpoint interval

Example (GaAs quantum wire):

100e-9     # L      — 100 nm wire
5e-9       # Delta0 — 5 nm thickness
1.5        # gap    — 1.5 eV band gap
0.07       # me     — GaAs electron mass
0.45       # mh     — GaAs hole mass
100e-3     # HO     — 100 meV level separation
1e12       # gam_e  — 1 ps electron lifetime
1e12       # gam_h  — 1 ps hole lifetime
1e12       # gam_eh — 1 ps interband dephasing
9.1        # epsr   — AlAs host dielectric
36e-3      # Oph    — 36 meV LO phonon (GaAs)
3e-3       # Gph    — 3 meV phonon damping
0.0        # Edc    — no DC field
500        # jmax   — output every 500 steps
20000      # ntmax  — checkpoint every 20000 steps

---

mb.params — Many-Body Physics Flags

This is the most important configuration file. Each line is a boolean flag (1 = enabled, 0 = disabled) that toggles a specific physics interaction. By flipping these flags, you can run anything from a bare optical Bloch equation to a full many-body simulation — without changing a single line of code.

Line	Flag	Physics
1	Optics	Light-matter coupling via dipole operator
2	Excitons	Excitonic correlations and band-gap renormalization (Hartree-Fock)
3	EHs	Electron-hole pair scattering
4	Screened	Screened Coulomb interactions (RPA)
5	Phonon	LO phonon scattering (Frohlich interaction)
6	DCTrans	DC transport (carrier drift under applied field)
7	LF	Longitudinal field / plasmon modes
8	FreePot	Free charge potential
9	DiagDph	Diagonal dephasing (population decay)
10	OffDiagDph	Off-diagonal dephasing (coherence decay)
11	Recomb	Spontaneous emission (radiative recombination)
12	PLSpec	Photoluminescence spectrum output
13	Ignorewire	Single-wire mode (skip inter-wire coupling)
14	Xqwparams	Write susceptibility diagnostic files
15	LorentzDelta	Use Lorentzian broadening for delta functions

Example (full many-body simulation):

1          # Optics
1          # Excitons
1          # EHs
1          # Screened
1          # Phonon
1          # DCTrans
1          # LF (Plasmonics)
0          # Free Potential
1          # DiagDph
1          # OffDiagDph
1          # Recomb
0          # PLSpec
0          # Ignorewire
1          # Xqwparams
0          # LorentzDelta

See Building Simulations for how to combine these flags for different physics regimes.

---

pulse.params — Optical Pulse Configuration

Defines the laser pulse that drives the simulation.

Line	Parameter	Units	Description
1	dimensions	—	Spatial dimensionality (1, 2, or 3)
2	n0	—	Background refractive index
3	lam	m	Laser wavelength
4	E00	V/m	Peak electric field amplitude
5	tw0	s	Pulse width
6	chirp	rad/s^2	Pulse chirp
7	xw	m	Beam width in X (2D/3D)
8	zw	m	Beam width in Z (3D)
9	Tpeak1	s	Pulse peak time (1D/2D)
10	Tpeak3	s	Pulse peak time (3D)
11	Ystart	m	Starting Y position
12	Xstart	m	Starting X position (2D/3D)
13	Zstart	m	Starting Z position (3D)
14	Nt/Toc	—	Time points per optical cycle
15	Ny/lambda	—	Y grid points per wavelength
16	Nx/lambda	—	X grid points per wavelength
17	Nz/lambda	—	Z grid points per wavelength
18	Nt	—	Total optical cycles to simulate
19	Ywin	m	Y window width
20	Xwin	m	X window width (2D/3D)
21	Zwin	m	Z window width (3D)
22	jmax	—	Output interval
23	nmax	—	Maximum time steps
24	Restart	bool	Resume from checkpoint (0/1)

---

space.params — Spatial Grid

Defines the computational grid for field propagation.

Line	Parameter	Units	Description
1	Dimensions	—	1, 2, or 3
2	Nx	—	Grid points in X
3	Ny	—	Grid points in Y
4	Nz	—	Grid points in Z
5	dx	m	Pixel spacing in X
6	dy	m	Pixel spacing in Y
7	dz	m	Pixel spacing in Z
8	epsilon_r	—	Background dielectric constant

---

qwarray.params — Quantum Wire Array

Configures the geometry of quantum wire arrays.

Line	Parameter	Units	Description
1	QW	bool	Include quantum wire calculations (0/1)
2	Nw	—	Number of quantum wires
3	y0	m	Wire placement along X axis
4	dxqw	m	Wire-to-wire spacing
5	a0_y	m	SHO oscillator length in Y
6	a0_z	m	SHO oscillator length in Z

---

pstd_abc.params — Absorbing Boundary Conditions

Controls the absorbing boundary layer for the PSTD grid to prevent reflections at domain edges.

Line	Parameter	Units	Description
1	Flag	bool	Enable ABC (0/1)
2	Value 1	m	Boundary layer parameter
3	Value 2	m	Boundary layer parameter
4	Flag	bool	Secondary ABC flag (0/1)
5	Value 3	m	Boundary layer parameter
6	Value 4	m	Boundary layer parameter

---

How Parameters Flow into the Simulation

All parameter files are read once during InitializeSBE. The initialization sequence is:

InitializeSBE(q, rr, r0, Emax, lam, Nw, QW)
  ├── read qw.params   → material constants (gap, masses, dephasing)
  ├── read mb.params    → physics flags (which interactions are ON)
  ├── InitializeQWOptics()     (always)
  ├── InitializeCoulomb()      (always)
  ├── InitializeDephasing()    (always)
  ├── InitializePhonons()      (if Phonon = 1)
  ├── InitializeDC()           (if DCTrans = 1)
  └── InitializeEmission()     (if Recomb = 1)

Once initialized, QWCalculator runs all enabled physics self-consistently at every time step. There is no runtime flag switching — to change the physics, re-initialize.

Template Files

Default parameter templates are provided in src/pulsesuite/PSTD3D/params/templates/. Copy them as a starting point for new simulations:

cp src/pulsesuite/PSTD3D/params/templates/*.params params/