arXiv subjects

H. Ritsch

Publications and source records attributed to H. Ritsch.

22 records · Page 2Linked to original sources

arXiv2001

An optical kaleidoscope using a single atom

A new method to track the motion of a single particle in the field of a high-finesse optical resonator is described. It exploits near-degenerate higher-order Gaussian cavity modes, whose symmetry is broken by the phase shift on the light induced by the particle. Observation of the spatial intensity distribution behind the cavity allows direct determination of the particle's position with approximately wavelength accuracy. This is demonstrated by generating a realistic atomic trajectory using a semiclassical simulation including friction and diffusion and comparing it to the reconstructed path. The path reconstruction itself requires no knowledge about the forces on the particle.

quant-ph↗

arXiv2000

Observation of decoherence with a movable mirror

Recently it has been proposed to use parity as a measure of the mechanism behind decoherence or the transformation from quantum to classical. Here, we show that the proposed experiment is more feasible than previously thought, as even an initial thermal state would exhibit the hypothesized symmetry breaking.

quant-ph↗

arXiv1999

On the observation of decoherence with a movable mirror

Following almost a century of debate on possible `independent of measurement' elements of reality, or `induced' elements of reality - originally invoked as an ad-hoc collapse postulate, we propose a novel line of interference experiments which may be able to examine the regime of induced elements of reality. At the basis of the proposed experiment, lies the hypothesis that all models of 'induced' elements of reality should exhibit symmetry breaking within quantum evolution. The described {\em symmetry experiment} is thus aimed at being able to detect and resolve symmetry breaking signatures.

quant-ph↗

arXiv1996

An all-optical gray lattice for atoms

We create a gray optical lattice structure using a blue detuned laser field coupling an atomic ground state of angular momentum J simultaneously to two excited states with angular momenta J and J-1. The atoms are cooled and trapped at locations of purely circular polarization. The cooling process efficiently accumulates almost half of the atomic population in the lowest energy band which is only weakly coupled to the light field. Very low kinetic temperatures are obtained by adiabatically reducing the optical potential. The dynamics of this process is analysed using a full quantum Monte Carlo simulation. The calculations explicitly show the mapping of the band populations on the corresponding momentum intervals of the free atom. In an experiment with subrecoil momentum resolution we measure the band populations and find excellent absolut agreement with the theoretical calculations.

physics.atom-ph↗