Showing papers by "Jörg Schmiedmayer published in 1996"

Inertial sensing with classical atomic beams

Abstract: A different approach to high-precision measurement of rotation, acceleration, and gravitation is presented. Our Moir\'e deflectometer is based on geometric propagation of an atomic (or molecular) beam through a set of three identical gratings. Accelerated movements of the gratings with respect to the atomic beam result in a change of the total transmitted intensity. The device is nondispersive, i.e., atoms with a broad energy distribution and without collimation can be used. Furthermore, rotational and linear (gravitational) acceleration can easily be distinguished and measured simultaneously. In a certain sense the Moir\'e deflectometer represents the classical analog to a quantum-mechanical matter-wave interferometer. Experimental results on a test system demonstrate that its sensitivity to rotation and gravitation is already in the range of commercially used inertial sensors. It can be increased straightforwardly by orders of magnitude. \textcopyright{} 1996 The American Physical Society.

Atom waves in crystals of light

Abstract: We present experiments studying the coherent motion of atoms in crystals made from on and off resonant light. The experiments confirm that inside the light-field atoms fulfilling the Bragg condition form a standing matter wave pattern. As a consequence we observed anomalous transmission of atoms through resonant light fields.

Coherent Frequency Shift of Atomic Matter Waves.

Abstract: We demonstrate how Bragg diffraction of atomic matter waves at a time-modulated thick standing light wave can be used to coherently shift the de Broglie frequency of the diffracted atoms. The coherent frequency shift is experimentally confirmed by interferometric superposition of modulated and unmodulated atoms resulting in time-dependent interference fringes. Our frequency shifter for atomic matter waves is a generalization of an acousto-optic frequency shifter for photons. [S0031-9007(96)01871-6]

Trapping polar molecules with a charged wire

Abstract: We consider the interaction of a small polar molecule with the electric field produced by a charged wire. We conjecture that such molecules, if rotationally cold, can perform stable orbital motion around the wire. Experimental conditions to realize such wire traps are considered.

Modulation of atomic de Broglie waves using Bragg diffraction

Abstract: Bragg diffraction of atoms at thick standing light waves requires that the wave-matching condition is fulfilled. This usually means that the atomic beam crosses the light wave exactly at the Bragg angle. Nevertheless, our experiments also demonstrate Bragg diffraction at detuned angles if the amplitude of the standing light wave is temporally modulated with an appropriate frequency. If, on the other hand, the phase of the light wave is modulated no diffraction is observed. Both modulation processes produce frequency sidebands which set up `slowly travelling standing waves' in front of a retro-reflection mirror. Atoms are diffracted at these `almost standing' light waves in a similar way to photons at the travelling sound waves in an acousto-optic modulator. The frequency of the diffracted de Broglie waves is assumed to be shifted by the intensity modulation frequency. The different results using amplitude- and phase-modulated light waves are due to interference between the diffraction contributions of the individual frequency sidebands contained in the standing light wave.

Classical and quantum binding of a particle with arbitrary spin in the magnetic field of a current-carrying wire: a simple guide for atoms

Abstract: A neutral atom with a magnetic moment can be bound to, and guided along, a current-carrying wire. The atom is attracted to regions of high field strength (high-field seeking state) and repelled from the wire by the centrifugal barrier. In the classical regime the atoms move in Kepler-like orbits. In the quantum regime, the system resembles a two-dimensional hydrogen atom in Rydberg-like states. The wire replaces the nucleus and the atom plays the role of the electron. We give a quantum mechanical and a classical description of the system. We rigorously prove the existence of infinitely many bound states for zero or finite wire cross section and any spin (F) of the atom. The bound-state energies closely follow a Coulomb-like behaviour with an effective angular momentum, .

Particle with arbitrary spin in the magnetic field of a linear current

Abstract: We investigated the bound-state spectrum of a particle with spin F> 1 2 in the magnetic field of a thin currentcarrying wire. We prove the existence of infinitely many bound states for any F . The bound-state energies closely follow a Coulomb-like behavior with an effective angular momentum l *, suggesting a high adiabaticity of the system. Numerical results (F5 1 2,. . . ,3) are well approximated by a single simple formula for the quantum defect, which is more accurate than the approximations given in the literature. We find a qualitative disagreement with the result obtained by adiabatic approximation. @S1050-2947~96!51309-0#

An Interferometer for Atoms with Standing Light Waves

Abstract: All experimentally realized atom interferometers may be divided into two classes. In atomic state interferometers,1,2 the beam splitter produces a superposition of internal states. The process of producing the superposition of internal states is the mechanism for coherently splitting the beams. In the other class of interferometers the beam splitter does not change the internal state of the atom. Rather, diffraction produces a superposition of external states and thus directly creates distinctly different paths in real space. In these de Broglie wave interferometers the beam splitting process — up till now only realized by diffraction at material double slits or material gratings — is directly linked to the wave nature of the external motion.