Liquids reveal their secrets: a theory that changes the rules of the game

Understanding solids and gases relies on theories about their basic properties, such as energy and heat capacity. These theories were developed more than 100 years ago. On the other hand, there was no similar theory for the third state of matter, the liquid state, until recently.

This was due to the underlying issues involved. A new book by Kostya Trashchenko, professor of physics at Queen Mary University of London, “Fluid theory(Fluid Theory) provides a theory of the most important properties of fluids.

Challenges of fluid theory

Fundamental problems related to the theory of fluids have been discussed extensively, for example, by Landau, Lifshitz and Pitaevsky, who claimed that no general theory of fluids is possible because fluids have no small parameter.

In addition to this theoretical gap, the absence of a general theory of fluids has had detrimental consequences for teaching fluids to students.

Fluid theory book

the book “Fluid theoryProfessor Trashchenko presents a theory about the most important properties of liquids, such as their energy and heat capacity. It explains recent developments in theory, experimentation, and modeling that have allowed us to understand agitation behavior in fluids and the effect of this behavior on energy, heat capacity, and other fundamental properties.

Recent developments and repercussions

Professor Trashchenko (QMUL) reviews the history of research on liquids, beginning with the first attempts of Sommerfeld and Brillouin who sought to understand liquids on the basis of phonons, at the same time that Einstein and Debye published their papers on solids.

He then shows that the properties of liquids can be explained on the basis of the collective excitation of phonons, with an important property: the phase space available to phonons in liquids is not fixed as in solids, but variable.

In particular, this phase space decreases with temperature, which explains a wide range of experimental results such as the reduction of the specific heat of liquids from solid to gaseous value with temperature.

Synthetic

the book “Fluid theory“It addresses the liquid state and its properties across the entire phase diagram, including subcritical fluids, supercritical fluids, and viscous fluids in the glass processing range. It also discusses how advances in fluid theory have led to other unexpected discoveries, such as the quantum viscosity minimum.”

For better understanding

What is the fluid theory?

Fluid theory is a way of understanding fundamental properties of fluids, such as energy and heat capacity, based on collective excitations and phonons.

Why was it difficult to develop fluid theory?

Fluid theory has been difficult to develop because of fundamental problems, such as the lack of a small modulus in fluids, which makes it difficult to develop a general theory.

What are the implications of fluid theory in teaching?

Fluid theory allows the study of fluids to be integrated into statistical or condensed matter physics courses, providing students with a more complete understanding of states of matter.

What is the minimum quantum viscosity?

The quantum minimum viscosity is a discovery from liquid theory that suggests that liquid-based life, like water-based life, is well suited to fundamental physical constants.

Who is the book “The Theory of Fluids” for?

the book “Fluid theory“It is aimed at scientists interested in states of matter, researchers and students in physics, chemistry and materials science, as well as teachers and students who want to incorporate the study of fluids into their courses.

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