Seminarium "Modeling of Complex Systems"

Quantum Electrodynamics has plenty of subjects of study, from high-energy physics of large particle accelerators to low-energy physics where the effects from quantum vacuum fields become more relevant. Though microscopic, these effects influence everyday phenomena—like gecko adhesion to walls and noble gas condensation. The interest in Casimir forces arose in the last century through studies of the effects of dispersive forces in colloids. Our work investigates how salt in water modifies these forces. By adjusting ion concentration, we control electrostatic screening, raising the central question: Can Casimir interactions be tuned by adding salt?According to the Dzyaloshinskii-Lifshitz-Pitaevskii (DLP) paradigm, two materials separated by a third medium with an intermediate dielectric constant experience repulsion. However, we show this paradigm fails in salted water due to the nonlocal ionic response. Focusing on silica–salted water- gold setup, we find that the zero-frequency contribution—dominant at distances near 100 nm and beyond—is altered, making the total Casimir force always attractive despite the DLP prediction.Our main findings are published in Phys. Rev. A 10.1103/PhysRevA.111.012816.

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The seminar will be held in hybrid mode: in room 1.40 (Faculty of Physics, UW) Join Zoom Meetinghttps://uw-edu-pl.zoom.us/j/94053335972?pwd=3ag9J6kMlYvbN6yJ7wmfo0G3bsaYWW.1 Meeting ID: 940 5333 5972Passcode: 220764 During the seminar the coffee and cakes are provided.