Fluctuation and dissipation in liquid-crystal electroconvection

Area of Science:

• Physics
• Materials Science
• Nonlinear Dynamics

Background:

• Liquid crystals exhibit complex behaviors under external stimuli.
• Phase transitions are critical phenomena in condensed matter physics.
• Understanding chaotic systems is crucial for various scientific fields.

Purpose of the Study:

• To investigate the phase transition in a liquid-crystal thin film under a steady-state current.
• To characterize the convective state and chaotic motion of rolls above the transition threshold.
• To analyze the power consumption, conductivity changes, and power fluctuations in relation to the Gallavotti-Cohen fluctuation theorem.

Main Methods:

• Maintaining a steady-state current through a liquid-crystal thin film.
• Applying a voltage and increasing it beyond a threshold to induce a phase transition.
• Measuring mean conductivity and power fluctuations.
• Comparing experimental results with the fluctuation theorem using an effective temperature.

Main Results:

• A phase transition to a convective state with chaotic roll motion was observed above a voltage threshold.
• Increased power consumption, indicated by higher mean conductivity, was noted above the transition.
• A sharp increase in the ratio of power fluctuations to mean dissipated power was detected post-transition.

Conclusions:

• The study demonstrates a voltage-induced phase transition in liquid crystals to a chaotic convective state.
• The observed increase in conductivity and power fluctuations provides insights into energy dissipation in nonlinear systems.
• The findings offer a comparison between experimental observations and theoretical predictions of the fluctuation theorem in a chaotic regime.