Related Experiment Video
Updated: Sep 13, 2025
08:55
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.6K
Nonstationary critical phenomena: Expanding the critical point
Richard E Spinney1,2, Richard G Morris1,2,3
1UNSW, School of Physics, Sydney, NSW 2052, Australia.
Physical Review. E
|August 1, 2025
Summary
We introduce biased quorum-sensing active particles (bQSAPs) to study dynamic critical phenomena in driven transport systems. This model reveals exotic phase structures and novel criticality beyond traditional single points.
Area of Science:
- Active Matter Physics
- Non-equilibrium Statistical Mechanics
- Soft Condensed Matter Theory
Background:
- Traditional critical phenomena are typically studied in equilibrium systems.
- Active matter systems exhibit non-equilibrium dynamics and persistent fluxes.
- Extending concepts of dynamic critical phenomena to driven transport is challenging.
Purpose of the Study:
- To develop a theoretical framework for dynamic critical phenomena in symmetry-broken active matter.
- To investigate the phase structure and criticality of biased quorum-sensing active particles (bQSAPs).
- To analyze the role of non-equilibrium fluxes and fluctuations in phase separation.
Main Methods:
- Construction of an effective field theory with a nonstationary order parameter.
- Development of a framework for interpreting bQSAP properties in inertial frames.
- Analysis of phase boundary movement using effective chemical potentials and free energy density.
Main Results:
- An anomalous coarsening behavior and an exotic phase structure where binodals can cross spinodal lines.
- Criticality is extended along a line, not confined to a single point, entering a pseudocritical region.
- Fluctuations remain relevant at macroscopic scales, exhibiting growth and nontrivial dispersion relations.
Conclusions:
- The study establishes a new paradigm for dynamic critical phenomena in driven active matter.
- bQSAPs exhibit unique phase behavior and criticality, distinct from equilibrium systems.
- Interplay of fluctuations and transport leads to diverse micro- and meso-phase separation regimes.
Related Concept Videos
01:18pV-Diagrams
4.4K
The pV diagram, which is a graph of pressure versus volume of the gas under study, is helpful in describing certain aspects of the substance. When the substance behaves like an ideal gas, the ideal gas equation describes the relationship between its pressure and volume. On a pV diagram, it is common to plot an isotherm, which is a curve showing p as a function of V with the number of molecules and the temperature fixed. Then, for an ideal gas, the product of the pressure of the gas and its...
4.4K
01:19Phase Diagram
6.1K
The phase of a given substance depends on the pressure and temperature. Thus, plots of pressure versus temperature showing the phase in each region provide considerable insights into the thermal properties of substances. Such plots are known as phase diagrams. For instance, in the phase diagram for water (Figure 1), the solid curve boundaries between the phases indicate phase transitions (i.e., temperatures and pressures at which the phases coexist).
6.1K
02:39Phase Transitions: Vaporization and Condensation
18.6K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase...
18.6K
01:27Thermal expansion and Thermal stress: Problem Solving
1.3K
San Francisco's Golden Gate Bridge is exposed to temperatures ranging from -15 °C to 40 °C. At its coldest, the main span of the bridge is 1275 m long. Assuming that the bridge is made entirely of steel, what is the change in its length between these temperatures?
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in...
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in...
1.3K
02:39Phase Transitions: Melting and Freezing
13.2K
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...
13.2K
01:24Heat and Free Expansion
2.1K
The work done by a thermodynamic system depends not only on the initial and final states but also on the intermediate states—that is, on the path. Like work, when heat is added to a thermodynamic system, it undergoes a change of state, and the state attained depends on the path from the initial state to the final state. Consider an ideal gas cylinder fitted with a piston. When the cylinder is heated at a constant temperature, the gas molecules absorb energy and expand slowly in a...
2.1K