arXiv subjects

Martin Stoll

Publications and source records attributed to Martin Stoll.

77 records · Page 5Linked to original sources

arXiv2005

Production of three-body Efimov molecules in an optical lattice

We study the possibility of associating meta-stable Efimov trimers from three free Bose atoms in a tight trap realised, for instance, via an optical lattice site or a microchip. The suggested scheme for the production of these molecules is based on magnetically tunable Feshbach resonances and takes advantage of the Efimov effect in three-body energy spectra. Our predictions on the energy levels and wave functions of three pairwise interacting 85Rb atoms rely upon exact solutions of the Faddeev equations and include the tightly confining potential of an isotropic harmonic atom trap. The magnetic field dependence of these energy levels indicates that it is the lowest energetic Efimov trimer state that can be associated in an adiabatic sweep of the field strength. We show that the binding energies and spatial extents of the trimer molecules produced are comparable, in their magnitudes, to those of the associated diatomic Feshbach molecule. The three-body molecular state follows Efimov's scenario when the pairwise attraction of the atoms is strengthened by tuning the magnetic field strength.

cond-mat.other↗

arXiv2004

Matter diffraction at oblique incidence: Higher resolution and the Helium Trimer Efimov state

We study the diffraction of atoms and weakly-bound three-atomic molecules from a transmission grating at non-normal incidence. Due to the thickness of the grating bars the slits are partially shadowed. Therefore, the projected slit width decreases more strongly with the angle of incidence than the projected period, increasing, in principle, the experimental resolution. The shadowing, however, requires a revision of the theory of atom diffraction. We derive an expression in the style of the Kirchhoff integral of optics and show that the diffraction pattern exhibits a characteristic asymmetry which must be accounted for when comparing with experimental data. We then analyze the diffraction of weakly bound trimers and show that their finite size manifests itself in a further reduction of the slit width by (3/4) where is the average bond length. The improved resolution at non-normal incidence may in particular allow to discern, by means of their bond lengths, between the small ground state of the helium trimer ( =1 nm, Barletta and Kievsky, Phys. Rev. A 64, 042514 (2001)) and its predicted Efimov-type excited state ( =8 nm, ibid.), and in this way to experimentally prove the existence of this long-sought Efimov state.

quant-ph↗

arXiv2003

Diffraction of Weakly Bound Clusters: Spectroscopy and Size Effects

Exciting experiments in the field of atom and molecule optics have lately drawn much attention to the effects involved in the coherent diffraction of particle beams. We review the influence of the finite size of the particles and of their energy level spectrum on the diffraction pattern. In turn, we demonstrate how experimental diffraction measurements allow to determine these quantities of weakly bound molecules by considering the diffraction of the dimer and trimer of helium, and the deuterium molecule dimer.

quant-ph↗

arXiv2002

Inelastic Diffraction and Spectroscopy of Very Weakly Bound Clusters

We study the coherent inelastic diffraction of very weakly bound two body clusters from a material transmission grating. We show that internal transitions of the clusters can lead to new separate peaks in the diffraction pattern whose angular positions determine the excitation energies. Using a quantum mechanical approach to few body scattering theory we determine the relative peak intensities for the diffraction of the van der Waals dimers (D_2)_2 and H_2-D_2. Based on the results for these realistic examples we discuss the possible applications and experimental challenges of this coherent inelastic diffraction technique.

quant-ph↗

arXiv2002

The van der Waals Potential between Metastable Atoms and Solid Surfaces: Novel Diffraction Experiments versus Theory

Highly polarizable metastable He* ($\mathrm{2^3S}$) and Ne* ($\mathrm{2^3P}$) atoms have been diffracted from a 100 nm period silicon nitride transmission grating and the van der Waals coefficients $C_3$ for the interaction of the excited atoms with the silicon nitride surface have been determined from the diffraction intensities out to the 10th order. The results agree with calculations based on the non-retarded Lifshitz formula.

quant-ph↗