19–20 Jun 2026
Université de Montréal (MIL campus)
Canada/Central timezone

Equation of State under External Stress from Crystals to Non-crystals

20 Jun 2026, 12:15
20m
A-2553

A-2553

Contributed Talk Condensed Matter Theory Condensed Matter Theory

Speaker

Gang Liu

Description

The rigorous Equation of State of any material under external isotropic pressure $P$:

$ \hspace{2.5cm} P =\frac {1}{\beta} \frac {\partial \ln Z}{\partial V}, $

based on the system partition function $Z$, is taught in almost every related textbook.

The Equation of State of crystals under general external stress $\mathbf{S}$ was derived:

$ \hspace{2.5cm} \mathbf{S} \cdot \mathbf{\sigma}_{\mathbf{h}}=-\frac {1}{\beta} \frac {\partial \ln Z}{\partial \mathbf{h}} \ \ \ (\mathbf{h}=\mathbf{a}, \mathbf{b}, \mathbf{c}), $

with respect to the crystal period vectors $\mathbf{h}$, in our recent article:

https://doi.org/10.1140/epjp/s13360-020-01010-6

which has been accessed about 23,000 times.

Here, we also derived the Equation of State of non-crystals under external stress and temperature and studied its relationship with the macroscopic mechanical equilibrium condition of the system. It has been published as the following preprint:

https://doi.org/10.20944/preprints202601.0293.v3

Author

Presentation materials