Measuring gravitational effect of superintense laser by spin-squeezed Bose—Einstein condensates interferometer

We consider an extremely intense laser, enclosed by an atom interferometer. The gravitational potential generated from the high-intensity laser is solved from the Einstein field equation under the Newtonian limit. We compute the strength of the gravitational force and study the feasibility of measuring the force by the atom interferometer. The intense laser field from the laser pulse can induce a phase change in the interferometer with Bose-Einstein condensates. We push up the sensitivity limit of the interferometer with Bose-Einstein condensates by spin-squeezing effect and determine the sensitivity gap for measuring the gravitational effect from intense laser by atom interferometer.     

Reaction imaging with interferometry

We analyze scattering into a double-slit interferometer with target-fragment recoil detection as a monitor of quantum correlation and entanglement in few-body reaction amplitudes. We thus investigate two-slit interference with which-way information as an enhancement to modern reaction-fragment detection. We briefly consider charged-particle scattering with recoil-ion detection from the point of view of quantum information.     

Spatial-Variant Geometric Phase of Hybrid-Polarized Vector Optical Fields

We investigate a novel spatial geometric phase of hybrid-polarized vector fields consisting of linear, elliptical and circular polarizations by Young's two-slit interferometer instead of the widely used Mach-Zehnder interferometer.This spatial geometric phase can be manipulated by engineering the spatial configuration of hybrid polarizations,and is directly related to the topological charge, the local states of polarization and the rotational symmetry of hybrid-polarized vector optical fields. The unique feature of geometric phase has implications in quantum information science as well as other physical systems such as electron vortex beams.     

Unsharp particle-wave duality in a photon split-beam experiment

In a quantum mechanical two-slit experiment one can observe a single photon simultaneously as particle (measuring the path) and as wave (measuring the interference pattern) if the path and the interference pattern are measured in the sense of unsharp observables. These theoretical predictions are confirmed experimentally by a photon split-beam experiment using a modified Mach—Zehnder interferometer.     

Atom Michelson interferometer on a chip using a Bose-Einstein condensate

An atom Michelson interferometer is implemented on an "atom chip." The chip uses lithographically patterned conductors and external magnetic fields to produce and guide a Bose-Einstein condensate. Splitting, reflecting, and recombining of condensate atoms are achieved by a standing-wave light field having a wave vector aligned along the atom waveguide. A differential phase shift between the two arms of the interferometer is introduced by either a magnetic-field gradient or with an initial condensate velocity. Interference contrast is still observable at 20% with an atom propagation time of 10 ms.     

Atomic Interference Method for Direct Measurement of the Wigner Function of a Cavity Field

We propose a scheme for the reconstruction of a cavity field state.In the scheme the cavity field is first displaced by a microwave source,and then is placed in front of one slit of the two-slit apparatus.Ground state stoms pass through the apparatus,hitting upon the screen far away from the two-slit apparatus.The atom-field interaction is dispersive.The contrast of interference fringes is directly related to the Wigner function for the field state.The scheme can be easily generalized to measure the Wigner function of an entangled state of two spatially separated single-mode cavities.     

Two-Slit and Aharonov-Bohm Experiments in Magnetic Field

We discuss the two-slit experiment and the Aharonov-Bohm (AB) experiment in the magnetic field. In such a case the electron moving in the magnetic field produces so called synchrotron radiation. In other words the photons are emitted from the points of the electron trajectory and it means that the trajectory of electron is visible in the synchrotron radiation spectrum. The axiomatic system of quantum mechanics does not enable to define the trajectory of the elementary particle. The two-slit experiment and AB experiment in a magnetic field was never performed and it means that they are the missing experiments of quantum mechanics. The extension of the discussion to the cosmical rays moving in the magnetic field of the Saturn magnetosphere and its rings is mentioned. It is related to the probe CASSINI. The solution of the problem in the framework of the hydrodynamical model of quantum mechanics and the nonlinear quantum mechanics is also mentioned.     

Cross correlation between the two modes in two-photon Jaynes-Cummings model in the presence of a classical homogeneous gravitational field

The temporal evolution of both the atomic population inversion of an effective two-level atom and the cross correlation between the two modes in two-photon Jaynes-Cummings model in the presence of a classical homogeneous gravitational field are investigated. To analyse the dynamical evolution of the atom-radiation system a quantum treatment of the internal and external dynamics of the atom is presented based on an alternative su(2) dynamical algebraic structure. By solving the Schr?dinger equation in the interaction picture, the evolving state of the system is found by which the influence of the gravitational field on the dynamical behavior of both the atomic population inversion of an effective two-level atom and the cross correlation between the two modes of the radiation field are explored. Assuming that initially the radiation field is prepared in the coherent state for each mode and an effective two-level atom is in a coherent superposition of the excited and ground states, the influence of gravity on both the atomic population inversion of an effective two-level atom and the cross correlation between the two modes of the radiation field are studied.     

用于原子干涉仪的拉曼光的制备

原子干涉仪是利用原子物质波的特性而实现的干涉仪,广泛应用于精密测量领域.在原子干涉仪中,通过拉曼光对原子进行相干操作,拉曼光的质量直接影响着干涉仪的技术指标.基于注入锁定技术,采用普通半导体激光器、声光调制器,实现了功率、频率和位相稳定的拉曼光的制备,并对拉曼光的相位噪声技术指标进行了测试.     

Topological phase shift in a cold-atom interferometer

Matter-wave interferences in a four-pulse version of a Ramsey-Bordé atom interferometer have been utilized to study phase shifts. A topological phase shift analogous to the scalar Aharonov-Bohm effect proposed for charged-particle interferences in the presence of a pulsed electrostatic potential has been investigated. The time-dependent potential has been generated by the interaction of a laser field with an induced atomic dipole without spatial variation along the interferometer arms. The atom interferometer has been run with laser-cooled magnesium atoms stored in a magneto-optical trap.Dedicated to H. Walther on the occasion of his 60th birthday     

Λ型和V型三能级原子与耦合腔相互作用系统中场的量子特性

研究了能级结构分别为Λ型三能级和V型三能级结构的两个原子和通过光纤耦合的由双模腔构成的复合系统中光场的压缩效应、二阶相干度和亚泊松分布等量子特性。利用数值计算方法讨论了光纤模与腔场间的耦合强度对量子特性的影响。研究结果表明:双模光场不呈现压缩效应,但呈现出反关联和亚泊松分布的量子特性;随着光纤模与腔场间耦合强度的增强,亚泊松分布减弱。     

Macroscopic manifestations of specific features of quantum statistics of the radiation field in the spectrum of resonance fluorescence

The fluorescence spectrum of a two-level atom excited by the field, whose state represents a superposition of the coherent states, is investigated. It is shown that to each mode of the quantum-statistical distribution of the incident field, a spectral mode of the scattered radiation corresponds, and one can determine the number of statistical modes of the incident field from the number of spectral modes of the scattered field. This result is a consequence of the fact that in the quasi-classical limit, statistical modes of the superimposed state interact with the atom independently of one another.     

Dynamic splitting and merging of an atom cloud on an atom chip

Chip-based atom interferometers bring together the advantages of atom chips and Bose--Einstein condensates. Their central prerequisite is that a condensate can be coherently split into two halves with a determined relative phase. This paper demonstrates the dynamical splitting and merging of an atom cloud with two U-wires on an atom chip. Symmetrical and asymmetrical splittings are realized by applying a bias field with dif\/ferent directions and magnitudes. The trajectories of the splitting are consistent with theoretical calculations. The atom chip is a good candidate for constructing an atom interferometer.     

基于复合干涉的光纤低相干干涉传感系统研究

研究一种能够进行远程及绝对测量的光纤低相干干涉传感系统。该系统包含两个光纤干涉仪,其中一个光纤干涉仪置于被测场中感应被测量的变化,可实现远程测量;另一个光纤干涉仪解调被测量的值。运用波分复用技术,使用于解调的光纤干涉仪同时工作于低相干干涉和高相干干涉状态。用低相干干涉信号决定被测量的幅值,对被测量实现绝对测量,并使测量量程不受波长限制;同时,用高相干干涉信号对被测量进行高精度的测量。系统的测量量程为6mm,测量分辨率小于1nm,位移实验结果的线性相关系数R为0.99。     

Exact Solutions for Jaynes-Cummings Models with Non-degenerate Two-Photon Transitions in the Ladder Configuration

In the present paper, the eigenfunctions and eigenvalues of the Hamiltonian of the interacting system have been obtained in two generalized Jaynes Cummings models separately, one in which the transition are mediated by two different modes of photon in the ladder configuration and the other involving two mode multi-photon interaction between the field and the atom. Effect of intensity dependent coupling between the field and the atom in both the above-mentioned cases have been investigated. Graphical features of the time dependence of population inversion have been analyzed when one of the field modes is prepared initially in a coherent state while the other one in a vacuum state.     

Effect of phase-damped cavity on dynamics of tangles of a nondegenerate two-photon JC model

A two-mode cavity field coupled to a two-level atom and damped by the environment through a phase-damped process is considered. For a chosen initial state, the effects of phase damping on the purity loss of the global system and different bipartite partitions of the system (atom-two modes, mode-(atom-mode)) through the tangles are considered. In particular, the effect of phase damping on the amount of entanglement between atom and field is evaluated by the negativity.     

A matter-wave interferometer based on the dc-Stark effect

We present a new separated beam atom interferometer in which the recombination of the atomic wave packet is due to the dc-Stark interaction of an induced atomic dipole with a cylindrically symmetric electric field of a charged wire. The fringe period shows a weak power-law dependence on the de Broglie wavelength and the polarizability of the particles. We present a semiclassical theoretical model for this interferometer which resembles the measured performance of the interferometer without free parameters. A discussion of possible applications of this interferometer for atoms and molecules is given. Received: 20 November 1998 / Published online: 8 September 1999     

Matter-wave decoherence due to a gas environment in an atom interferometer

Decoherence due to scattering from background gas particles is observed for the first time in a Mach-Zehnder atom interferometer, and compared with decoherence due to scattering photons. A single theory is shown to describe decoherence due to scattering either atoms or photons. Predictions from this theory are tested by experiments with different species of background gas, and also by experiments with different collimation restrictions on an atom beam interferometer.     

利用原子干涉仪的相位调制进行绝对转动测量

提出一种基于原子干涉仪的相位调制进行绝对转动测量的方法.以π/2-π-π/2构型的空间型原子干涉仪为例,通过对拉曼激光进行相位调制,然后在动量谱空间测量转动对原子速度谱的调制周期,获得原子干涉仪相对惯性空间的绝对转动.文章对于采用该法进行角速度测量的测量范围以及对相位调制频率的要求进行了分析,对于散粒噪声限下的转动测量灵敏度及其影响因素进行了仿真. 关键词： 原子干涉仪 原子陀螺 相位调制 绝对转动测量     

Remote and high precision step height measurement with an optical fiber multiplexing interferometric system

An optical fiber multiplexing low coherence and high coherence interferometric system, which includes a Fizeau interferometer as the sensing element and a Michelson interferometer as the demodulating element, is designed for remote and high precision step height measurement. The Fizeau interferometer is placed in the remote field for sensing the measurand, while the Michelson interferometer which works in both modes of low coherence interferometry and high coherence interferometry is employed for demodulating the measurand. The range of the step height is determined by the low coherence interferometry and the value of it is measured precisely by the high coherence interferometry. High precision has been obtained by searching precisely the peak of the low coherence interferogram symmetrically from two sides of the low coherence interferogram and stabilizing the Michelson interferometer with a feedback loop. The maximum step height that could be measured is 6 mm while the measurement resolution is less than 1 nm. The standard deviation of 10 times measurement results of a step height of 1 mm configurated with two gauge blocks is 0.5 nm.