Profile
Astrid Lambrecht
Physicist and chair of the Board of Directors of Forschungszentrum Jülich
Lambrecht studies quantum fluctuations and Casimir forces. She coauthored theoretical studies of Casimir interactions between spheres (2022) and parallel filaments in salt water (2024). The latter explores forces at cellular length scales; it proposes a possible contribution to filament bundling, rather than reporting that mechanism observed in living cells.
Affiliations
- Forschungszentrum Jülich (chair of the Board of Directors since 2023)
Channels
Bibliography
A bibliography listing does not establish authorship. Credits appear under attribution.
Published bibliography entries: 3. Showing 1–3 of 3.
Listed work
Paper · 2024
Universal Casimir attraction between filaments at the cell scale
- Benjamin Spreng(Author)
- Hélène Berthoumieux(Author)
- Astrid Lambrecht(Author)
- Anne-Florence Bitbol(Author)
- Paulo Maia Neto(Author)
- Serge Reynaud(Author)
Spreng and colleagues start from the fact that the Casimir interaction between dielectric objects in salty water contains a universal part the solvent does not screen, so it reaches over long distances. That non-screened universal force has already been measured experimentally, on a microsphere held by optical tweezers next to a larger fixed sphere. They derive the Casimir free energy for two parallel dielectric cylinders with the scattering method. Its magnitude far exceeds the thermal energy scale over a wide range, including the sizes of actin filaments and microtubules in cells. At every distance of biological interest the free energy depends only on geometry, not on the cylinders' dielectric response. This universal attraction should help hold bundles of parallel filaments together.
Listed work
Paper · 2022
Universal Casimir interactions in the sphere–sphere geometry
- Tanja Schoger(Author)
- Benjamin Spreng(Author)
- Gert-Ludwig Ingold(Author)
- Astrid Lambrecht(Author)
- Paulo A. Maia Neto(Author)
- Serge Reynaud(Author)
Schoger, Spreng, Ingold, Lambrecht, Maia Neto and Reynaud study universal Casimir interactions between spheres in two configurations that turn out to be dual. One has Drude-model metal spheres in vacuum, the other dielectric spheres in salt water beyond the Debye screening length. In both, the long-distance or high-temperature limit is dominated by low-frequency transverse magnetic thermal fluctuations. The results do not depend on material details, because metals and salt water both have finite conductivity and so an infinite static dielectric constant. Their dependence on geometry is also universal, linked to an approximate conformal invariance of the reduced free energy.
Listed work
Paper · 2019
Scattering theory of the screened Casimir interaction in electrolytes
- Paulo A. Maia Neto(Author)
- Felipe S. S. Rosa(Author)
- Luis B. Pires(Author)
- Anna B. Moraes(Author)
- Antoine Canaguier-Durand(Author)
- Romain Guérout(Author)
- Astrid Lambrecht(Author)
- Serge Reynaud(Author)
Maia Neto, Rosa, Pires, Moraes, Canaguier-Durand and Guérout apply the scattering approach to the Casimir interaction between two dielectric half-spaces separated by an electrolyte. They include the nonlocal response created by mobile ions and add longitudinal channels, coupled to transverse ones by reflection at the dielectric surface. The interaction energy follows from the matrix describing a round trip of these coupled waves between the surfaces. For all nonzero Matsubara frequencies the electrolyte acts almost like a local medium, so those contributions are nearly unaffected by the ions. At zero frequency, longitudinal channels give a term screened over about a Debye length, while an unscreened transverse-magnetic term sets the long-distance limit of the interaction.