Fundamentals

This section provides the conceptual background needed to understand what Homodyne does and why it works.

• What is X-ray Photon Correlation Spectroscopy?
  • Introduction
  • The Coherent X-ray Requirement
  • From Speckles to Correlation Functions
  • Two-Time Correlation Functions
  • Connection to Particle Dynamics
  • Homodyne Detection
  • Why XPCS for Soft Matter?
  • Experimental Setup
  • See Also
• Analysis Modes
  • Overview
  • Static Mode
  • Laminar Flow Mode
  • Choosing Between Modes
  • Per-Angle Scaling
  • Mode-Specific Parameter Counts
  • See Also
• Homodyne Package Overview
  • What Homodyne Does
  • What Homodyne Does Not Do
  • Key Design Decisions
  • Package Architecture
  • Data Flow
  • Comparison with Other XPCS Analysis Tools
  • Installation
  • Version Information
  • See Also
• Parameter Interpretation Guide
  • Overview
  • Diffusion Parameters
  • Shear Parameters (laminar_flow only)
  • Optical Parameters
  • Parameter Reference Table
  • Setting Initial Values
  • Overriding Parameter Bounds via YAML
  • Cross-System Bounds Consistency
  • See Also

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What you will learn:

• What X-ray Photon Correlation Spectroscopy (XPCS) measures and how the two-time correlation function C2 encodes dynamics.

• The core homodyne equation relating C2 to the intermediate scattering function C1.

• The difference between static and laminar_flow analysis modes and when to use each.

• How Homodyne’s physics model translates experimental parameters into a predicted C2 matrix.

Prerequisites: No prior XPCS or JAX experience required for this section.