Showing papers by "Udo Seifert published in 2006"
TL;DR: The first lawlike balance between applied work, exchanged heat, and internal energy on the level of a single trajectory is demonstrated, and the observed distribution of applied work is distinctly non-Gaussian in good agreement with numerical calculations.
Abstract: We study the motion of an overdamped colloidal particle in a time-dependent nonharmonic potential. We demonstrate the first lawlike balance between applied work, exchanged heat, and internal energy on the level of a single trajectory. The observed distribution of applied work is distinctly non-Gaussian in good agreement with numerical calculations. Both the Jarzynski relation and a detailed fluctuation theorem are verified with good accuracy.
297 citations
TL;DR: In this article, the violation of the fluctuation-dissipation theorem (FDT) is connected to breaking detailed balance, by measuring the velocity with respect to the local mean velocity.
Abstract: In a nonequilibrium steady state, the violation of the fluctuation-dissipation theorem (FDT) is connected to breaking detailed balance. For the velocity correlations of a driven colloidal particle we calculate an explicit expression of the FDT violation. The equilibrium form of the FDT can be restored by measuring the velocity with respect to the local mean velocity.
220 citations
TL;DR: This work directly measures entropy production of a single two-level system realized experimentally as an optically driven defect center in diamond and demonstrates that the total entropy production obeys various exact relations for finite time trajectories.
Abstract: Using fluorescence spectroscopy we directly measure entropy production of a single two-level system realized experimentally as an optically driven defect center in diamond. We exploit a recent suggestion to define entropy on the level of a single stochastic trajectory [Seifert, Phys. Rev. Lett. 95, 040602 (2005)10.1103/PhysRevLett.95.040602]. Entropy production can then be split into one of the system itself and one of the surrounding medium. We demonstrate that the total entropy production obeys various exact relations for finite time trajectories.
113 citations
TL;DR: In this article, the authors analyzed the instability of the capsule shape and used the length scale separation between the capsule radius and the wrinkling wavelength to derive analytical results both for the threshold value of the shear rate and for the critical wavelength of wrinkling.
Abstract: Elastic capsules can exhibit short wavelength wrinkling in external shear flow. We analyse this instability of the capsule shape and use the length scale separation between the capsule radius and the wrinkling wavelength to derive analytical results both for the threshold value of the shear rate and for the critical wavelength of the wrinkling. These results can be used to deduce elastic parameters from experiments.
60 citations
TL;DR: Two new control mechanisms for antagonist-induced deadhesion are identified and a new method is provided for the determination of the receptor binding affinity of either the surface-embedded ligands or the competing antagonist molecules.
31 citations
TL;DR: The thermal fluctuation spectrum of a fluid membrane coupled harmonically to a solid support by an array of tethers is calculated and possible applications cover pillar-supported or polymer-tethered membranes.
Abstract: The thermal fluctuation spectrum of a fluid membrane coupled harmonically to a solid support by an array of tethers is calculated. For strong tethers, this spectrum exhibits nonmonotonic, anisotropic behavior with a relative maximum at a wavelength about twice the tether distance. The root-mean-square displacement is evaluated to estimate typical membrane displacements. Possible applications cover pillar-supported or polymer-tethered membranes.
19 citations
TL;DR: The adhesion of microcapsules to an attractive contact potential is studied theoretically and the axisymmetric shape equations are solved numerically.
Abstract: The adhesion of microcapsules to an attractive contact potential is studied theoretically. The axisymmetric shape equations are solved numerically. Beyond a universal threshold strength of the potential, the contact radius increases in proportion to the square root of the strength. Scaling functions for the corresponding amplitudes are derived as a function of the elastic parameters.
15 citations
TL;DR: In this paper, the adhesion of microcapsules to an attractive contact potential is studied theoretically and scaling functions for corresponding amplitudes are derived as a function of the elastic parameters.
Abstract: The adhesion of microcapsules to an attractive contact potential is studied theoretically. The axisymmetric shape equations are solved numerically. Beyond a universal threshold strength of the potential, the contact radius increases like a square root of the strength. Scaling functions for the corresponding amplitudes are derived as a function of the elastic parameters.
1 citations
TL;DR: In this article, entropy change along a single stochastic trajectory of a biomolecule is discussed for two different sources of non-equilibrium entropy, and the total entropy change obeys an integral fluctuation theorem and a class of further exact relations.
Abstract: Entropy production along a single stochastic trajectory of a biomolecule is discussed for two different sources of non-equilibrium. For a molecule manipulated mechanically by an AFM or an optical tweezer, entropy production (or annihilation) occurs in the molecular conformation proper or in the surrounding medium. Within a Langevin dynamics, a unique identification of these two contributions is possible. The total entropy change obeys an integral fluctuation theorem and a class of further exact relations, which we prove for arbitrarily coupled slow degrees of freedom including hydrodynamic interactions. These theoretical results can therefore also be applied to driven colloidal systems. For transitions between different internal conformations of a biomolecule involving unbalanced chemical reactions, we provide a thermodynamically consistent formulation and identify again the two sources of entropy production, which obey similar exact relations. We clarify the particular role degenerate states have in such a description.
1 citations
TL;DR: In this paper, the authors analyzed the instability of the capsule shape and used the length scale separation between the capsule radius and the wrinkling wavelength to derive analytical results both for the threshold value of the shear rate and for the critical wave-length of the wrinkles.
Abstract: Elastic capsules can exhibit short wavelength wrinkling in external shear flow. We analyse this instability of the capsule shape and use the length scale separation between the capsule radius and the wrinkling wavelength to derive analytical results both for the threshold value of the shear rate and for the critical wave-length of the wrinkling. These results can be used to deduce elastic parameters from experiments.