Related Experiment Video
Updated: Dec 5, 2025
10:08
Phase Behavior of Charged Vesicles Under Symmetric and Asymmetric Solution Conditions Monitored with Fluorescence Microscopy
Published on: October 24, 2017
9.5K
Lifshitz phase transitions in a one-dimensional Gamma model.
Zi-An Liu1,2, Tian-Cheng Yi1,2, Jin-Hua Sun3
1College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China.
Physical Review. E
|October 20, 2020
Summary
This study explores quantum phase transitions in a spin-1/2 Gamma model. Competing interactions lead to Lifshitz transitions and topological changes in the Fermi surface, signaled by entanglement measures.
Area of Science:
- Condensed Matter Physics
- Quantum Magnetism
- Materials Science
Background:
- The Gamma model describes off-diagonal exchange interactions in one-dimensional systems.
- Strong spin-orbit couplings are crucial for understanding magnetic properties.
Purpose of the Study:
- Investigate quantum phase transitions and magnetic properties of the spin-1/2 Gamma model.
- Analyze the role of competing exchange interactions on the ground state.
- Characterize the rich phase diagram and Lifshitz transitions.
Main Methods:
- Theoretical study of a one-dimensional spin-1/2 Gamma model.
- Analysis of competing nearest-neighbor and second-neighbor interactions.
- Investigation of spinless fermion semimetallic ground states.
- Topological characterization of Fermi surface using Weyl nodes.
Main Results:
- Identified a rich phase diagram with three gapless phases.
- Observed Lifshitz transitions characterized by changes in Weyl node types (I and II).
- Found a coexistence of type-I and type-II Weyl nodes in phase II.
- Demonstrated that entanglement measures (concurrence, entropy) signal second-order transitions.
Conclusions:
- The Gamma model provides an exactly solvable platform for studying Lifshitz transitions.
- Topological changes in the Fermi surface occur without symmetry breaking.
- Entanglement measures are effective indicators of quantum phase transitions in correlated electron systems.
Related Concept Videos
02:31Phase Transitions
22.0K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
22.0K
02:39Phase Transitions: Melting and Freezing
14.3K
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...
14.3K
02:33Phase Transitions: Sublimation and Deposition
19.3K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
19.3K
01:12Fermi Level Dynamics
523
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
523
02:39Phase Transitions: Vaporization and Condensation
20.2K
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 molecules...
20.2K
01:10First Law: Particles in One-dimensional Equilibrium
7.7K
Newton's first law of motion states that a body at rest remains at rest, or if in motion, remains in motion at constant velocity, unless acted on by a net external force. It also states that there must be a cause for any change in velocity (a change in either magnitude or direction) to occur. This cause is a net external force. For example, consider what happens to an object sliding along a rough horizontal surface. The object quickly grinds to a halt, due to the net force of friction. If...
7.7K