Showing papers by "Jörg Schmiedmayer published in 1995"
TL;DR: The Talbot effect, the self-imaging of a periodic structure, with atom waves is demonstrated, and the successive recurrence of these self-images is measured as a function of the distance from the imaged grating.
Abstract: We have demonstrated the Talbot effect, the self-imaging of a periodic structure, with atom waves. We have measured the successive recurrence of these self-images as a function of the distance from the imaged grating. This is a near-field interference effect, which has several possible applications that are discussed.
238 citations
TL;DR: Experiments are discussed here in which this entanglement results from the elastic scattering of a photon from an atom initially in a state with extended spatial coherence inside an atom interferometer.
Abstract: Loss of coherence in one system A that results from entanglement or correlation with a reservoir M has long been an important issue in quantum mechanics. It is of special interest both because of the difficulty of incorporating the resulting coherence loss into Schrodinger’s equation describing system A and because of its relevance to understanding the measurement process in particular and the connection between quantum mechanics and classical mechanics in general [1]. We discuss experiments here in which this entanglement results from the elastic scattering of a photon from an atom initially in a state with extended spatial coherence inside an atom interferometer. The major issues addressed are the degree of loss of coherence (ie. contrast of the interference fringes), both when the outgoing photon is ignored (ie. treated as a reservoir) and when information about its final state is inferred from the final momentum of the atom. This inference is exact since momentum (and energy too) is conserved and the initial momentum of both photon and atom are well specified.
215 citations
TL;DR: In this paper, an atom interferometer with interfering beams that are physically isolated by a metal foil was constructed, and the phase shift induced from the quadratic Stark effect was analyzed.
Abstract: We have constructed an atom interferometer with interfering beams that are physically isolated by a metal foil. By applying an interaction to one of the two interfering beams, we can measure ground-state energy shifts with a spectroscopic precision of 6.6\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}14}$ eV/\ensuremath{\surd}min , or 16 Hz/\ensuremath{\surd}min . Applying an electric field to one beam of the interferometer, we have measured the phase shift induced from the quadratic Stark effect. By analyzing these phase shifts, we have determined the ground-state polarizability of sodium, with much improved accuracy, to be 24.11(6${)}_{\mathrm{statistical}}$(6${)}_{\mathrm{systematic}}$\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}24}$ ${\mathrm{cm}}^{3}$.
200 citations
TL;DR: This new atom interferometer is the exact mirror image of interferometers for light, with the roles of atoms and photons interchanged, and it directly demonstrates coherence of the diffraction of atomic waves at standing light waves.
Abstract: We have developed a novel interferometer for atom de Broglie waves, where amplitude division and recombination is achieved by diffraction at standing light waves operating as phase gratings. Our new atom interferometer is the exact mirror image of interferometers for light, with the roles of atoms and photons interchanged, and it directly demonstrates coherence of the diffraction of atomic waves at standing light waves. Easy manipulation of the phase, intensity, and polarization of the standing light wave permits novel studies of atomic coherence properties.
180 citations
TL;DR: An intense, pure beam of sodium molecules (Na2) is produced by using light forces to separate the atomic and molecular species in a seeded supersonic beam using diffraction from a microfabricated grating and a molecule interferometer with fully separated beams and high contrast fringes.
Abstract: We have produced an intense, pure beam of sodium molecules (Na2) by using light forces to separate the atomic and molecular species in a seeded supersonic beam. We used diffraction from a microfabricated grating to study the atomic and molecular sodium in the beam. Using three of these gratings, we constructed a molecule interferometer with fully separated beams and high contrast fringes. We measured both the real and imaginary parts of the index of refraction of neon gas for Na2 molecule de Broglie waves by inserting a gas cell in one arm of the interferometer. PACS numbers: 03.75.‐b, 07.77.Gx, 34.20.Gj Quantum mechanical treatment of the center-of-mass motion of increasingly complex systems is an important theme in modern physics. This issue is manifest theoretically in studies of the transition from quantum through mesoscopic to classical regimes and experimentally in efforts to coherently control and manipulate the external spatial coordinates of complex systems (e.g., matter wave optics and interferometry). Recently, matter wave optics and interferometry have been extended to atoms with the many techniques for the coherent manipulation of the external degrees of freedom of atoms constituting a new
120 citations
TL;DR: By inserting a gas cell in one arm of an atom interferometer, both the attenuation and the phase shift of a sodium matter wave that passes through monatomic or molecular gases are measured.
Abstract: By inserting a gas cell in one arm of an atom interferometer, we have measured both the attenuation and the phase shift of a sodium matter wave that passes through monatomic (He, Ne, Ar, Kr, and Xe) or molecular gases (${\mathrm{N}}_{2}$, C${\mathrm{O}}_{2}$, N${\mathrm{H}}_{3}$, and ${\mathrm{H}}_{2}$O). This determines the complex index of refraction for Na matter waves and, more accurately, the ratio of the real to the imaginary part of the forward scattering amplitude. These measurements are compared with several semiclassical scattering models.
77 citations
68 citations
TL;DR: In this article, the interaction of a polarizable atom with the electric field of a charged wire alone is not possible because of the 1/r2 form of the interaction potential, however, one can build a microscopic trap with a combination of a magnetic field generated by a straight wire and the static electric field generated from a concentric charged ring which provides the longitudinal confinement.
Abstract: We present new ways of trapping a neutral atom with static electric and magnetic fields. We discuss the interaction of a neutral atom with the magnetic field of a current carrying wire and the electric field of a charged wire. Atoms can be trapped by the 1/r magnetic field of a current-carrying wire in a two-dimensional trap. The atoms move in Kepler-like orbits around the wire and angular momentum prevents them from being absorbed at the wire. Trapping was demonstrated in an experiment by guiding atoms along a 1 m long current-carrying wire. Stable traps using the interaction of a polarizable atom with the electric field of a charged wire alone are not possible because of the 1/r2 form of the interaction potential. Nevertheless, we show that one can build a microscopic trap with a combination of a magnetic field generated by a current in a straight wire and the static electric field generated by a concentric charged ring which provides the longitudinal confinement. In all of these traps, the neutral atoms are trapped in a region of maximal field, in theirhigh-field seeking state.
44 citations
TL;DR: In this paper, the velocity distribution is chopped into a series of narrow peaks such that the velocity dependence of the phase shifts will result in a rephasing of the interference for certain strengths of applied potential.
Abstract: We describe a novel velocity-selection technique for measuring dispersive phase shifts in matter-wave interferometers. Where conventional velocity-selection techniques simply reduce the width of the initial velocity distribution, here, the velocity distribution is chopped into a series of narrow peaks such that the velocity dependence of the phase shifts will result in a rephasing of the interference for certain strengths of applied potential. This technique overcomes limitations due to wide and poorly known velocity distributions and thus allows a better determination of the applied interaction with complete independence from the initial velocity distribution of the beam.
11 citations
2 citations