Related Experiment Video
Updated: Jul 2, 2025
08:25
Measurements of Local Instantaneous Convective Heat Transfer in a Pipe - Single and Two-phase Flow
Published on: April 30, 2018
7.2K
How heat propagates in liquid 3He
Kamran Behnia1, Kostya Trachenko2
1Laboratoire de Physique et d'Étude des Matériaux, (ESPCI - CNRS - Sorbonne Université), PSL Research University, Paris, France. Kamran.Behnia@espci.fr.
Nature Communications
|February 27, 2024
Summary
Normal liquid helium-3 deviates from standard behavior when fermion-fermion scattering time falls below Planckian time. Collective excitations, or sound modes, likely carry heat, explaining observed thermal conductivity.
Area of Science:
- Condensed Matter Physics
- Quantum Fluids
Background:
- Landau's Fermi liquid theory describes transport via quasi-particle scattering.
- Normal liquid 3He adheres to this theory only at very low temperatures.
Purpose of the Study:
- Investigate deviations from standard Fermi liquid behavior in liquid 3He.
- Identify the mechanism responsible for heat transport at higher temperatures.
Main Methods:
- Analyzed experimental data of liquid 3He from 0.007 K to 3 K.
- Proposed a model incorporating quasi-particle and collective excitation contributions to thermal conductivity.
Main Results:
- Observed that deviations correlate with fermion-fermion scattering times below the Planckian time.
- Demonstrated that thermal diffusivity is bounded by fundamental constants.
- Identified a sound mode with specific wavevector and mean free path as a heat carrier.
- Showed that thermal conductivity is a sum of quasi-particle and sound contributions.
Conclusions:
- Collective excitations (sound modes) act as significant heat carriers in liquid 3He.
- The proposed two-component model accurately explains experimental thermal conductivity data.
- Findings suggest a minimum thermal diffusivity bound applicable to quantum and classical liquids.
Related Concept Videos
01:25Heat Capacities of an Ideal Gas III
2.2K
The number of independent ways a gas molecule can move along straight line, rotate, and vibrate is called its degrees of freedom. Supposing d represents the number of degrees of freedom of an ideal gas, the molar heat capacity at constant volume of an ideal gas in terms of d is
2.2K
02:44Heating and Cooling Curves
22.8K
When a substance—isolated from its environment—is subjected to heat changes, corresponding changes in temperature and phase of the substance is observed; this is graphically represented by heating and cooling curves.
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
22.8K
01:12Heat Flow and Specific Heat
5.4K
Heat is a type of energy transfer that is caused by a temperature difference, and it can change the temperature of an object. Since heat is a form of energy, its SI unit is the joule (J). Another common unit of energy often used for heat is the calorie (cal), which is defined as the energy needed to change the temperature of 1 g of water by 1 °C, specifically between 14.5 °C and 15.5 °C, since the energy needed shows a slight temperature dependence. Another commonly used unit is...
5.4K
01:14Mechanisms of Heat Transfer I
4.2K
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
4.2K
01:20Conduction, Convection and Radiation: Problem Solving
1.2K
There are three methods by which heat transfer can take place: conduction, convection, and radiation. Each method has unique and interesting characteristics, but all three have two things in common: they transfer heat solely because of a temperature difference; and the greater the temperature difference, the faster the heat transfer.
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...
1.2K
02:39Phase Transitions: Melting and Freezing
12.4K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
12.4K