Papers by Eloisa Marchesoni
Classical and Quantum Gravity, 2014
Physical review. E, Statistical, nonlinear, and soft matter physics, 2015
We numerically investigate the motion of active artificial microswimmers diffusing in a fuel conc... more We numerically investigate the motion of active artificial microswimmers diffusing in a fuel concentration gradient. We observe that, in the steady state, their probability density accumulates in the low-concentration regions, whereas a tagged swimmer drifts with velocity depending in modulus and orientation on how the concentration gradient affects the self-propulsion mechanism. Under most experimentally accessible conditions, the particle drifts toward the high-concentration regions (pseudochemotactic drift). A correct interpretation of experimental data must account for such an "anti-Fickian" behavior.
EPL (Europhysics Letters), 2015
Classical and Quantum Gravity, 2014
Advances in Chemical Physics, 1985
The Fokker-Planck equation, better known among biologists as the Kolmogorov forward equation, was... more The Fokker-Planck equation, better known among biologists as the Kolmogorov forward equation, was introduced into the field of population genetics by Wright'in 1945. Since then a variety of stochastic processes in the change of gene frequencies have been treated by means of this approach, from random sampling of gametes in linite populations to random fluctuations in systematic evolutionary pressures, of which fluctuation of selection intensity is especially relevant. It is clear, therefore, that this field could be investigated with the ...
Statistical Physics and Thermodynamics of Nonlinear Nonequilibrium Systems, 1993
Twenty Years After NEEDS '79, 2000
Many one-dimensional systems may be modeled as thermalized elastic strings moving on either perio... more Many one-dimensional systems may be modeled as thermalized elastic strings moving on either periodic (multistable) or bistable substrates. Popular examples in condensed matter physics are dislocations in crystalline lattices 1, 2 magnetic flux vortex lines in type-II superconducting samples 3, triple lines in surface wetting problems 4, propagating flux quanta in Josephson transmission lines 5, to mention but a few topics of ongoing research. Broadly speaking, all of the objects listed above, can be regarded as linear imperfections ...
Physics Letters A, 1996
A series of tests on the geometry and the materials of the mechanical clamps of the suspensions f... more A series of tests on the geometry and the materials of the mechanical clamps of the suspensions for the test masses of a large interferometric gravity wave detector (VIRGO project) has been carried out with the purpose of improving the clamp design. A significant decrease of the losses due to the stick-and-slip mechanism on the clamp surfaces has been obtained by increasing and localizing the clamping pressure on the heads of the suspension wires or strips (monolithic suspensions). The total losses thus measured compare well ...
Experimental Physics of Gravitational Waves - Proceedings of the International Summer School, 2000
A gravitational wave interferometer must detect very small displacements of free masses which are... more A gravitational wave interferometer must detect very small displacements of free masses which are hung as mechanical pendulums. Once seismic noise is filtered, the dominant noise source between 10 and 50 Hz is likely to be the thermal noise of the pendulum motion. One way to reduce this noise source is to construct the pendulum with as high a mechanical Q as possible in order to concentrate the thermal motion in a narrow band around the pendulum resonant frequency.
Physical Review Letters, 1997
The unlocking of a linear defect (like a lattice dislocation or a magnetic flux line is a type-II... more The unlocking of a linear defect (like a lattice dislocation or a magnetic flux line is a type-II superconductor) from a periodic substrate is modeled by a damped elastic string subjected to a washboard potential. At low temperatures running solutions are shown to set in for tilt amplitudes larger than a certain threshold value, sensitive to the damping constant. Close to the unlocking threshold the motion of a string segment is characterized by a logarithmic transient dynamics; as a consequence, hysteresis effects become observable for forcing ...
Physical Review B, 2001
Soliton-bearing field theories have been advocated to model a variety of physical processes in pa... more Soliton-bearing field theories have been advocated to model a variety of physical processes in particle physics, 1 soft matter such as polymers and magnetic chains, 2, 3 dislocation theory, 4–6 and magnetic vortex-line dynamics. 7–9 In the continuum limit both the dynamics of a single soliton and the statistical mechanics of a dilute gas of solitons are well understood. 10, 11 Discreteness, however, is an unavoidable complication, which rests upon two orders of motivations. a In most applications the physical system at hand is ...
Philosophical Magazine A, 1998
Abstract The apparent conflict between two experimental estimates of the Peierls stress in fcc me... more Abstract The apparent conflict between two experimental estimates of the Peierls stress in fcc metals, σB from Bordoni peak experiments and σf from low-temperature plastic flow measurements, is settled within the standard Peierls model of dislocation dynamics. We prove that the Peierls stress is estimated correctly by σB, the ratio σf/σB being proportional to the (small) dislocation damping constant.
Physics Letters A, 1995
Thermally driven escape over a barrier which fluctuates with Gaussian statistics is studied by me... more Thermally driven escape over a barrier which fluctuates with Gaussian statistics is studied by means of analog simulation. The phenomenon of resonant activation [CR Doering and JC Gadoua, Phys. Rev. Lett. 69 (1992) 2318] occurs when the correlation-time of the barrier fluctuations is increased without changing the amplitude. The dependence of the relevant escape time on the fluctuation variance exhibits a number of properties, independent of the potential shape, which eluded previous investigations.
Physics Letters A, 1990
Abstract Stochastic relaxation in a strongly nonlinear one-dimensional potential driven by band-l... more Abstract Stochastic relaxation in a strongly nonlinear one-dimensional potential driven by band-limited noise is investigated by means of analogue simulation. On suitably high-pass filtering the stochastic process under study, intermittent bursts become observable. Most statistical properties related with this phenomenon appear to be universal, ie independent of the noise statistics, over a wide frequency range.
Classical and Quantum Gravity, 2014
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Papers by Eloisa Marchesoni