Related Experiment Video
Updated: Jul 23, 2025

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Rigorous Bounds on Transport from Causality
Michal P Heller1, Alexandre Serantes2, Michał Spaliński3,4
1Department of Physics and Astronomy, Ghent University, 9000 Ghent, Belgium.
Abstract:
We use causality to derive a number of simple and universal constraints on dispersion relations, which describe the location of singularities of retarded two-point functions in relativistic quantum field theories. We prove that all causal dissipative dispersion relations have a finite radius of convergence in cases where stochastic fluctuations are negligible. We then give two-sided bounds on all transport coefficients in units of this radius, including an upper bound on diffusivity.
Related Concept Videos
Reynolds Transport Theorem
Criteria for Causality: Bradford Hill Criteria - II
Space-Time Curvature and the General Theory of Relativity
This has been verified in many experiments. However, space and time are no longer absolute. Two observers moving relative to one another do not agree on the length of objects or the passage of time. The mechanics of objects based on Newton's laws of...
Criteria for Causality: Bradford Hill Criteria - I
Schwarzschild Radius and Event Horizon
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
The Uncertainty Principle

