Observation of phase correlations in ferrofluids

Magnetic fluids, also known as ferrofluids, are excellent candidates for several important research fields, including soft robotics and biomedicine. In this study, we report on the observation of phase correlations between two physically isolated and electromagnetically shielded volumes of ferrofluid. A "twinning" pre-conditioning process, involving the application of hysteresis cycles to the entire fluid volume, was performed to induce a coherent state. Subsequently, the fluid was divided into two separate, shielded containers, with one subjected to an electrical stimulus. We observed statistically significant correlations in the impedance fluctuations between the stimulated and non-stimulated samples, even at a separation distance of up to 10 meters. These correlations persist for approximately 100 hours under laboratory conditions and were consistently observed in both water-based and hydrocarbon-based ferrofluids within a temperature range of 10-50 °C. The experimental design excludes classical electromagnetic fields as the mediating force. These findings suggest the presence of a long-range, collective phenomenon in ferrofluids, opening new avenues for investigating complex interactions in colloidal systems.