Classical and Quantum Causal Interventions.

Area of Science:

• Causal inference and quantum information theory.
• Foundations of physics and scientific methodology.

Background:

• Causal models are essential tools for predicting outcomes of interventions across scientific disciplines.
• Recent advancements have extended causal modeling concepts to quantum systems, introducing quantum causal structure.
• Interventions are fundamental to causal modeling, providing empirical meaning to these models.

Purpose of the Study:

• To investigate the physical basis of interventions in both classical and quantum causal modeling.
• To determine if the idealized interventions used in causal discovery are physically realizable.
• To explore the thermodynamic constraints on performing interventions.

Main Methods:

• Physical analysis of interventions within classical and quantum causal frameworks.
• Examination of the role of thermodynamics, measurement, and feedback in open systems.
• Theoretical demonstration of the impossibility of perfect 'atomic' or 'surgical' interventions.

Main Results:

• Interventions in both classical and quantum systems are fundamentally constrained by the thermodynamics of open systems.
• The idealized 'do-calculus' interventions, assumed to be perfect and surgical, are shown to be physically impossible.
• Thermodynamic limitations impose fundamental restrictions on the precision and nature of causal interventions.

Conclusions:

• The concept of perfect interventions, central to classical and quantum causal modeling, lacks a physical basis.
• Thermodynamic principles necessitate a revision of how interventions are understood and modeled in physical systems.
• Future research in causal discovery must account for these physical limitations of interventions.