Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Statements of the Second Law of Thermodynamics

Statements of the Second Law of Thermodynamics

The second law of thermodynamics can be stated in several different ways, and all of them can be shown to imply the others. The Clausius’ statement of the second law of thermodynamics is based on the irreversibility of spontaneous heat flow. It states that heat will not flow from the colder body to the hotter body unless some other process is involved. Additionally, as per the Kelvin’s statement, it is impossible to convert the heat from a single source into work without any other...

Entropy and the Second Law of Thermodynamics

Entropy and the Second Law of Thermodynamics

Consider an isolated system in which a hot object is placed in contact with a cold one. This is an irreversible process that eventually leads both objects to reach the same equilibrium temperature. It is crucial to note that the constituents of any substance exhibit increased disorder at higher temperatures. As a cold substance absorbs heat, its constituents become more disordered. The energy transfer from a hotter object to a cooler one increases the system's disorder or randomness. This...

Entropy and the Second Law of Thermodynamics

Entropy and the Second Law of Thermodynamics

The second law of thermodynamics can be stated quantitatively using the concept of entropy. Entropy is the measure of disorder of the system.
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...

Entropy

Entropy

The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the entropy.
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...

Entropy

Entropy

Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has expanded in a vacuum remains dispersed and never spontaneously reassembles. The unidirectional nature of these phenomena is the result of a thermodynamic state function called entropy (S). Entropy is the measure of the extent to which the energy is dispersed throughout a system, or in other words, it is proportional to the degree of disorder of a...

Second Law of Thermodynamics

Second Law of Thermodynamics

In the quest to identify a property that may reliably predict the spontaneity of a process, a promising candidate has been identified: entropy. Processes that involve an increase in entropy of the system (ΔS > 0) are very often spontaneous; however, examples to the contrary are plentiful. By expanding consideration of entropy changes to include the surroundings, a significant conclusion regarding the relation between this property and spontaneity may be reached. In thermodynamic...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Variance sum rule for entropy production.

Science (New York, N.Y.)·2024

Same author

Thermodynamic bounds for diffusion in nonequilibrium systems with multiple timescales.

Physical review. E·2023

Same author

Power spectrum and critical exponents in the 2D stochastic Wilson-Cowan model.

Scientific reports·2022

Same author

On the fluctuation-dissipation relation in non-equilibrium and non-Hamiltonian systems.

Chaos (Woodbury, N.Y.)·2019

Same author

Forecasting of the first hour aftershocks by means of the perceived magnitude.

Nature communications·2019

Same author

Induced and endogenous acoustic oscillations in granular faults.

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences·2018

Search research articles

Related Experiment Video

Updated: Apr 30, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

Published on: December 4, 2017

Nonequilibrium fluctuation-dissipation theorem and heat production.

E Lippiello¹, M Baiesi², A Sarracino³

¹Department of Mathematics and Physics, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.

Physical Review Letters

|April 29, 2014

Summary

This study connects heat production to deviations from the fluctuation-dissipation theorem in nonequilibrium systems. The new framework applies to transient states and discrete processes, introducing a nonequilibrium effective temperature.

More Related Videos

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

Published on: June 1, 2016

Characterization of Thermal Transport in One-dimensional Solid Materials

Characterization of Thermal Transport in One-dimensional Solid Materials

Published on: January 26, 2014

Related Experiment Videos

Last Updated: Apr 30, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

Published on: December 4, 2017

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

Published on: June 1, 2016

Characterization of Thermal Transport in One-dimensional Solid Materials

Characterization of Thermal Transport in One-dimensional Solid Materials

Published on: January 26, 2014

Area of Science:

Statistical Mechanics
Non-equilibrium Thermodynamics
Physical Chemistry

Background:

The fluctuation-dissipation theorem (FDT) relates response functions to equilibrium fluctuations.
Extending FDT to non-equilibrium systems is crucial for understanding energy dissipation and heat production.
Existing formulations often apply only to steady states.

Purpose of the Study:

To establish a general relationship between heat production and deviations from the equilibrium fluctuation-dissipation theorem.
To extend existing theoretical frameworks to transient regimes and discrete processes.
To introduce concepts of two-time work, kinetic energy, and heat exchange in non-equilibrium systems.

Main Methods:

Utilizing the relationship between response and correlation functions in non-equilibrium systems.
Extending the Harada-Sasa formulation for Langevin equations.
Developing a general formulation incorporating two-time variables.

Main Results:

A direct connection is established between heat production and deviations from the equilibrium FDT.
The developed scheme is valid for transient regimes and discrete jump processes.
New concepts of two-time work, kinetic energy, and heat exchange are introduced, linked to a non-equilibrium effective temperature.

Conclusions:

The study provides a unified framework for analyzing heat production in diverse non-equilibrium systems.
The introduced concepts offer new tools for quantifying non-equilibrium thermodynamics.
Numerical simulations validate the theoretical framework for anharmonic oscillators and molecular motor models.