353 research outputs found
Work probability distribution and tossing a biased coin
We show that the rare events present in dissipated work that enters Jarzynski
equality, when mapped appropriately to the phenomenon of large deviations found
in a biased coin toss, are enough to yield a quantitative work probability
distribution for Jarzynski equality. This allows us to propose a recipe for
constructing work probability distribution independent of the details of any
relevant system. The underlying framework, developed herein, is expected to be
of use in modelling other physical phenomena where rare events play an
important role.Comment: 6 pages, 4 figures
Assembly and force measurement with SPM-like probes in holographic optical tweezers
We report a high fidelity tomographic reconstruction of the quantum state of photon pairs generated by parametric down-conversion with orbital angular momentum (OAM) entanglement. Our tomography method allows us to estimate an upper and lower bound for the entanglement between the down-converted photons. We investigate the two-dimensional state subspace defined by the OAM states ±ℓ and superpositions thereof, with ℓ=1, 2, ..., 30. We find that the reconstructed density matrix, even for OAMs up to around ℓ=20, is close to that of a maximally entangled Bell state with a fidelity in the range between F=0.979 and F=0.814. This demonstrates that, although the single count-rate diminishes with increasing ℓ, entanglement persists in a large dimensional state space
The Kawasaki identity and the fluctuation theorem
In this paper we show that the Fluctuation Theorem of Evans and Searles [D. J. Evans, D. J. Searles, Phys. Rev. E 50, 1645 (1994)] implies that the Kawasaki function is unity for all time t. We confirm this relationship using experimental data obtained using optical tweezers, and show that the Kawasaki function is a valuable diagnostic tool
Reversibility in nonequilibrium trajectories of an optically trapped particle
The measure of irreversibility as the dissipation function that serves as the quantitative argument in the fluctuation theorem (FT) was investigated. The FT describes the system's thermodynamic irreversibility developed in time from a completely thermodynamically reversibble system at short times to a thermodynamically irreversible one at infinitely long times. It was observed that the ensemble average of ωt was positive definite irrespective of the system for which it was constructed. It was found that the different expressions for ωt can arise in stochastic and deterministic systems
Non-spherical optically trapped probes: Design, control, and applications
In this proceedings paper we show describe how a microtool can be assembled, and tracked in three dimensions such that its full rotational and translational coordinates, q, are recovered. This allows tracking of the motion of any arbitrary point, d, on the microtool's surface. When the micro-tool is held using multiple optical traps the motion of such a point investigates the inside of an ellipsoidal volume - we term this a 'thermal ellipsoid. We demonstrate how the shape of this thermal ellipsoid may be controlled by varying the relative trapping power of the optical traps, and adjusting the angle at which the micro-tool is held relative to the focal plane. Our experimental results follow the trends derived by Simpson and Hanna
An optically actuated surface scanning probe
We demonstrate the use of an extended, optically trapped probe that is capable of imaging surface topography with nanometre precision, whilst applying ultra-low, femto-Newton sized forces. This degree of precision and sensitivity is acquired through three distinct strategies. First, the probe itself is shaped in such a way as to soften the trap along the sensing axis and stiffen it in transverse directions. Next, these characteristics are enhanced by selectively position clamping independent motions of the probe. Finally, force clamping is used to refine the surface contact response. Detailed analyses are presented for each of these mechanisms. To test our sensor, we scan it laterally over a calibration sample consisting of a series of graduated steps, and demonstrate a height resolution of ∼ 11 nm. Using equipartition theory, we estimate that an average force of only ∼ 140 fN is exerted on the sample during the scan, making this technique ideal for the investigation of delicate biological samples
Special Lagrangian cones with higher genus links
For every odd natural number g=2d+1 we prove the existence of a countably
infinite family of special Lagrangian cones in C^3 over a closed Riemann
surface of genus g, using a geometric PDE gluing method.Comment: 48 page
Probing Ganymede's atmosphere with HST Ly images in transit of Jupiter
We report results from far-ultraviolet observations by the Hubble Space
Telescope of Jupiter's largest moon Ganymede transiting across the planet's
dayside hemisphere. {Within} a targeted campaign on 9 September 2021 two
exposures were taken during one transit passage to probe for attenuation of
Jupiter's hydrogen Lyman- dayglow above the moon limb. The background
dayglow is slightly attenuated over an extended region around Ganymede, with
stronger attenuation in the second exposure when Ganymede was near the planet's
center. In the first exposure when the moon was closer to Jupiter's limb, the
effects from the Ganymede corona are hardly detectable, likely because the
Jovian Lyman- dayglow is spectrally broader and less intense at this
viewing geometry. The obtained vertical H column densities of around
~cm are consistent with previous results.
Constraining angular variability around Ganymede's disk, we derive an upper
limit on a local HO column density of ~cm, such
as could arise from outgassing plumes in regions near the observed moon limb
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