Topological transitions in an oscillatory driven liquid crystal cell

Area of Science:

• Physics
• Materials Science
• Non-equilibrium Thermodynamics

Background:

• Matter exhibits diverse states (solid, liquid, gas, plasma) under equilibrium conditions.
• Exotic states like Bose-Einstein condensates and superconductivity emerge from topological changes, persisting out of equilibrium.

Purpose of the Study:

• Investigate topological states of matter out of thermodynamic equilibrium.
• Explore the effects of energy injection and dissipation via oscillatory forcing on topological states.

Main Methods:

• Experimentally studied a liquid crystal cell under low-frequency oscillatory electric fields.
• Analyzed vortex formation, self-organization (square lattices, glassy states), and topological transitions.
• Utilized a stochastic amplitude equation and numerical simulations.

Main Results:

• Observed a transition from a non-vortex to a persistent vortex state (topological transition).
• Vortices self-organized into various structures (square lattices, glassy states) depending on forcing parameters.
• Identified continuous and discontinuous topological transitions based on forcing waveform (sawtooth, square, sinusoidal).

Conclusions:

• Non-equilibrium matter, driven by temporal parameter modulation, can exhibit exotic topological states.
• The transition mechanism involves a balance between stochastic vortex creation and deterministic annihilation.
• Demonstrated the emergence of ordered structures like square vortex lattices in driven systems.