RESUMO
In this study, we report on the stabilization of a continuous-wave Ti:Sa laser to an optical frequency comb. The laser is emitting at 866 nm to address one of the transitions required for Doppler cooling of a single 40Ca+ ion in a linear Paul trap (2D3/2 âP1/22). The stabilized Ti:Sa laser is utilized to calibrate an ultra-accurate wavelength meter. We certify this self-reference laser source by comparing the results from monitoring the laser-cooled 40Ca+ ion in the linear Paul trap, with those obtained when a HeNe laser is used for calibration. The use of this self-reference is compatible with the simultaneous use of the comb for precision spectroscopy in the same ion-trap experiment.
RESUMO
We use extensive computer simulations to probe local thermodynamic equilibrium (LTE) in a quintessential model fluid, the two-dimensional hard-disks system. We show that macroscopic LTE is a property much stronger than previously anticipated, even in the presence of important finite-size effects, revealing a remarkable bulk-boundary decoupling phenomenon in fluids out of equilibrium. This allows us to measure the fluid's equation of state in simulations far from equilibrium, with an excellent accuracy comparable to the best equilibrium simulations. Subtle corrections to LTE are found in the fluctuations of the total energy which strongly point to the nonlocality of the nonequilibrium potential governing the fluid's macroscopic behavior out of equilibrium.