Gravitational-wave detection with matter-wave interferometers based on standing light waves

We study the possibility of detecting gravitational-waves with matter-wave interferometers, where atom beams are split, deflected and recombined totally by standing light waves. Our calculation shows that the phase shift is dominated by terms proportional to the time derivative of the gravitational wave amplitude. Taking into account future improvements on current technologies, it is promising to build a matter-wave interferometer detector with desired sensitivity.     

HYPER: A Satellite Mission in Fundamental Physics Based on High Precision Atom Interferometry

The article presents the HYPER project, a proposal for a satellite mission on precision matter-wave interferometry. For the mission several scientific objectives are under investigation, for which atom interferometers proved on ground to be a true complementary and competitive alternative for classical concepts: The application of atom interferometers as gyroscopes, the measurement of the gravitational acceleration (including tests of the universality of the free fall of atoms) and the precise determination of the fine-structure constant. The paper focuses on the use of cold-atom gyroscopes to map the Lense-Thirring effect close by the Earth and reports on results of recent feasibility studies of the European Space Agency. HYPER requires new concepts of compact, high-resolution matter-wave gyroscopes, which are better adapted to the use in satellite based experiments. The article will give a concise overview of the status and strategies in the field.     

Micromanipulation of neutral atoms with nanofabricated structures

A large variety of trapping and guiding potentials can be designed by bringing cold atoms close to charged or current carrying material objects. We describe the basic principles of constructing microscopic traps and guides and how to load atoms into them. The simplicity and versatility of these methods will allow for miniaturization and integration of atom optical elements into matter-wave quantum circuits on Atom Chips. These could form the basis for robust and widespread applications in atom optics, ranging from fundamental studies in mesoscopic physics to possibly quantum information systems. Received: 20 December 1999 / Revised version: 7 March 2000 / Published online: 5 April 2000     

The Sagnac effect: 20 years of development in matter-wave interferometry

Since the first atom interferometry experiments in 1991, measurements of rotation through the Sagnac effect in open-area atom interferometers have been investigated. These studies have demonstrated very high sensitivity that can compete with state-of-the-art optical Sagnac interferometers. Since the early 2000s, these developments have been motivated by possible applications in inertial guidance and geophysics. Most matter-wave interferometers that have been investigated since then are based on two-photon Raman transitions for the manipulation of atomic wave packets. Results from the two most studied configurations, a space-domain interferometer with atomic beams and a time-domain interferometer with cold atoms, are presented and compared. Finally, the latest generation of cold atom interferometers and their preliminary results are presented.     

Quantum Theory of Atom-Wave Beam Splitters and Application to Multidimensional Atomic Gravito-Inertial Sensors

We review the theory of atom-wave beam splitters using atomic transitions induced by electromagnetic interactions. Both the spatial and temporal dependences of the e.m.³ fields are introduced in order to compare the differences in momentum transfer which occur for pulses either in the time or in the space domains. The phases imprinted on the matter-wave by the splitters are calculated in the limit of weak e.m. and gravitational fields and simple rules are derived for practical atom interferometers. The framework is applicable to the Lamb-Dicke regime. Finally, a generalization of present 1D beam splitters to 2D or 3D is considered and leads to a new concept of multidimensional atom interferometers to probe inertial and gravitational fields especially well-suited for space experiments.     

Microchip traps and Bose–Einstein condensation

The article gives an overview of the rapidly evolving field of magnetic microchip traps (also called ‘atom chips’) for neutral atoms. Special attention is given to Bose–Einstein condensation in such traps, to the particular properties of microchip trap potentials, and to practical considerations in their design. Scaling laws are developed, which lead to an estimate of the ultimate confinement that chip traps can provide. Future applications such as integrated atom interferometers are discussed. Received: 28 March 2002 / Published online: 14 May 2002     

A Radio-frequency Atomchip for Neutral Atoms

Present work aims to establish that a generalized notion of total noise may be used as a measure of depth of nonclassicality. Here it is shown that the minimum total noise （ Tmin ） can be used as a measure of depth of higher order squeezing. It is also shown that the Caruthers-Nieto quantum phase fluctuation parameter U, which is an indirect measure of total fluctuation in sine and cosine quantum phase operators, is a measure of depth of antibunching. As an specific example, interaction of intense laser beam with an inversion symmetric third order nonlinear medium is studied. In this physical system, existence of different nonclassical states （such as squeezing, antibunching, higher order squeezing etc. ） have already been reported by us. Present work establishes that an appropriate notion of total fluctuation can be used as a measure of nonclassicality in al these cases.     

A neutral atom and a wire: towards mesoscopic atom optics

A large variety of trapping and guiding potentials can be designed by bringing cold atoms close to charged or current-carrying material objects. Using a current-carrying wire we demonstrate how to build guides and traps for neutral atoms and using a charged wire we study a 1/r ² singularity. The simplicity and versatility of the principles demonstrated in our experiments will allow for miniaturization and integration of atom optical elements into matter-wave quantum circuits. Received: 13 December 1998 / Revised version: 8 July 1999 / Published online: 8 September 1999     

Using time-reversal symmetry for sensitive incoherent matter-wave Sagnac interferometry

We present a theory of the transmission of guided matter-waves through Sagnac interferometers. Interferometer configurations with only one input and one output port have a property similar to the phase rigidity observed in the transmission through Aharonov-Bohm interferometers in coherent mesoscopic electronics. This property enables their operation with incoherent matter-wave sources. High rotation sensitivity is predicted for high finesse configurations.     

对被囚禁原子质心运动基态波包的有效分束

文章简要地介绍了原子干涉现象及原子光学的发展历史和现状．在对各种不同的原子干涉仪工作原理进行简单总结之后，文章描述了包括文章作者在内的研究小组一项最新的理论工作．这个工作提出了一个对被囚禁原子质心运动基态波包进行有效分束的物理方案．     

Matter-wave bright solitons: Internal atomic recombination and external feeding

We consider matter-wave bright solitons in the presence of three-body atomic recombination, an axial periodic modulation and a feeding term, and use a variational method to derive conditions to have dynamically stabilized solitons due to compensation between the dissipation and alimentation of atoms from external sources. We critically examine how the BEC soliton is affected by the imbalance between the internal atom loss and external feeding. We pay special attention to study the influence of these terms on the soliton dynamics in optical lattice potentials that cause periodic modulation.     

Gravitational wave detection with single-laser atom interferometers

We present a new general design approach of a broad-band detector of gravitational radiation that relies on two atom interferometers separated by a distance L. In this scheme, only one arm and one laser will be used for operating the two atom interferometers. We consider atoms in the atom interferometers not only as perfect inertial reference sensors, but also as highly stable clocks. Atomic coherence is intrinsically stable and can be many orders of magnitude more stable than a laser. The unique one-laser configuration allows us to then apply time-delay interferometry to the responses of the two atom interferometers, thereby canceling the laser phase fluctuations while preserving the gravitational wave signal in the resulting data set. Our approach appears very promising. We plan to investigate further its practicality and detailed sensitivity analysis.     

Interferometer-type structures for guided atoms

We experimentally demonstrate interferometer-type guiding structures for neutral atoms based on dipole potentials created by microfabricated optical systems. As a central element we use an array of atom waveguides being formed by focusing a red-detuned laser beam with an array of cylindrical microlenses. Combining two of these arrays, we realize X-shaped beam splitters and more complex systems like the geometries for Mach-Zehnder and Michelson-type interferometers for atoms.     

Non-autonomous matter-wave solitons in hybrid atomic–molecular Bose–Einstein condensates with tunable interactions and harmonic potential

In this paper, we investigate matter-wave solitons in hybrid atomic–molecular Bose–Einstein condensates with tunable interactions and external potentials. Three types of time-modulated harmonic potentials are considered and, for each of them, two groups of exact non-autonomous matter-wave soliton solutions of the coupled Gross–Pitaevskii equation are presented. Novel nonlinear structures of these non-autonomous matter-wave solitons are analyzed by displaying their density distributions. It is shown that the time-modulated nonlinearities and external potentials can support exact non-autonomous atomic–molecular matter-wave solitons.     

对抛式冷原子陀螺仪中原子运动轨迹的控制

冷原子具有很小的速度,很窄的速度分布以及良好的相干特性,利用冷原子物质波干涉特性可实现原子干涉仪,具有萨格奈克效应的原子干涉仪即原子陀螺仪,可精密测量转动速率. 冷原子轨迹的精确控制对提高冷原子陀螺仪的测量精度有着重要的意义,文章报道了利用直接数字频率综合器,实现对双向对抛冷原子运动轨迹的精确控制. 关键词： 冷原子 原子陀螺仪 直接数字频率综合器     

Ideal multipole ion traps from planar ring electrodes

We present designs for multipole ion traps based on a set of planar, annular, concentric electrodes which require only rf potentials to confine ions. We illustrate the desirable properties of the traps by considering a few simple cases of confined ions. We predict that mm-scale surface traps may have trap depths as high as tens of electron volts when parameters of a magnitude common in the field are chosen. Under similar conditions, micromotion amplitudes in a 2D ion crystal as low as tens of nanometers could be realized. Several example traps are studied, and the scaling of those properties with voltage, frequency, and trap scale, for small numbers of ions, is derived. Applications of these traps include quantum information science, frequency metrology, and cold ion–atom collisions.     

Vibration-induced phase noise in Mach–Zehnder atom interferometers

The high inertial sensitivity of atom interferometers has been used to build accelerometers and gyrometers, but this property makes these interferometers very sensitive to the laboratory seismic noise. This seismic noise induces a phase noise which is large enough to reduce the fringe visibility in many cases. We develop here a model calculation of this phase noise applicable to a wide class of Mach–Zehnder atom interferometers and we apply this model to our thermal lithium interferometer. We are thus able to explain the observed dependence of the fringe visibility on the diffraction order. The dynamical model developed in the present paper should be very useful to further reduce this phase noise in atom interferometers and this reduction should open the way to improved interferometers. PACS 03.75.Dg; 39.20.+q; 42.50.Vk     

102ℏk large area atom interferometers

We demonstrate atom interferometers utilizing a novel beam splitter based on sequential multiphoton Bragg diffractions. With this sequential Bragg large momentum transfer (SB-LMT) beam splitter, we achieve high contrast atom interferometers with momentum splittings of up to 102 photon recoil momenta (102?k). To our knowledge, this is the highest momentum splitting achieved in any atom interferometer, advancing the state-of-the-art by an order of magnitude. We also demonstrate strong noise correlation between two simultaneous SB-LMT interferometers, which alleviates the need for ultralow noise lasers and ultrastable inertial environments in some future applications. Our method is intrinsically scalable and can be used to dramatically increase the sensitivity of atom interferometers in a wide range of applications, including inertial sensing, measuring the fine structure constant, and detecting gravitational waves.     

Demonstration of an area-enclosing guided-atom interferometer for rotation sensing

We demonstrate area-enclosing atom interferometry based on a moving guide. Light pulses along the free-propagation direction of a magnetic guide are applied to split and recombine the confined atomic matter-wave, while the atoms are translated back and forth along a second direction in 50 ms. The interferometer is estimated to resolve 10 times the earth rotation rate per interferometry cycle. We demonstrate a "folded figure 8" interfering configuration for creating a compact, large-area atom gyroscope with multiple-turn interfering paths.