Recently, it has been proposed that space-based atomic sensors may be used to detect gravitational waves. These proposals describe the sensors either as clocks or as atom interferometers. Here, we seek to explore the fundamental similarities and differences between the two types of proposals. We present a framework in which the fundamental mechanism for sensitivity is identical for clock and atom interferometer proposals, with the key difference being whether or not the atoms are tightly confined by an external potential. With this interpretation in mind, we propose two major enhancements to detectors using confined atoms, which allow for an enhanced sensitivity analogous to large-momentum-transfer (LMT) used in atom interferometry (though with no transfer of momentum to the atoms), and a way to extend the useful coherence time of the sensor beyond the atom's excited state lifetime.
A review is given of the implications of the absence of an intrinsic notion of instantaneous 3-space, so that a clock synchronization convention has to be introduced, for relativistic theories.
Atomic interference experiments test the universality of the coupling between matter-energy and gravity at different spacetime points, thus being in principle able to probe possible violations of the universality of the gravitational redshift (UGR). In this contribution, we introduce a UGR violation model and then discuss UGR tests performed by atomic clocks and atom interferometers on the same footing. We present a large class of atom-interferometric geometries which are sensitive to violations of UGR.
We propose a simplest detector of harmonic vibrations with micro amplitudes and low frequencies, i.e. the detector consisting of one atomic beam. Here the atomic beam is induced by a plane harmonic wave and has a classical collective harmonic vibrations, which vibrant directions are perpendicular to the wave vectors of atomic beam. Compared with the detector consisting of atomic Mach-Zehnder interferometer, the new detector has two advantages: (1) it is suitable for the detection of the harmonic vibrations induced either by a longitudinal plane harmonic wave or by a transverse plane harmonic w…
We analyze a method for serial writing of arbitrary two-dimensional patterns using optical focusing of a collimated atomic beam. A spatial light modulator is used in a side illumination geometry to create a localized optical spot with secondary maxima that are well separated from the central peak. Numerical simulation of a lithography experiment using a magneto-optical trap as a source of cold Cs atoms, collimation and cooling in a magnetic guide, and optical focusing predicts full width at half maximum pixel sizes of 110 x 110 nm and writing times of about $20 \rm ms$ per pixel.
The interatomic dipole-dipole interaction is commonly thought to be the main physical reason for spectroscopic effects nonlinear in atomic density. However, we have found that the free motion of atoms can lead to other effects nonlinear in atomic density $n$, using a previously unknown self-consistent solution of the Maxwell-Bloch equations in the mean-field approximation for a gas of two-level atoms with an optical transition at unperturbed frequency $ω^{}_0$. These effects distort the Doppler lineshape (shift, asymmetry, broadening), but are not associated with an atom-atom interaction. In p…
We describe the so-called "Lambda-Zeeman method" to investigate individual hyperfine transitions between Zeeman sublevels of atoms in an external magnetic field of 0.1 mT - 0.25 T. Atoms are confined in a nanocell with thickness L = Lambda, where Lambda is the resonant wavelength (794 nm or 780 nm for D1 or D2 line of Rb). Narrow resonances in the transmission spectrum of the nanocell are split into several components in a magnetic field; their frequency positions and probabilities depend on the B-field. Possible applications are described, such as magnetometers with nanometric spatial resolut…
Spherically-symmetric ground states of alkali-metal atoms do not posses electric quadrupole moments. However, the hyperfine interaction between nuclear moments and atomic electrons distorts the spherical symmetry of electronic clouds and leads to non-vanishing atomic quadrupole moments. We evaluate these hyperfine-induced quadrupole moments using techniques of relativistic many-body theory and compile results for Li, Na, K, Rb, and Cs atoms. For heavy atoms we find that the hyperfine-induced quadrupole moments are strongly (two orders of magnitude) enhanced by correlation effects. We further a…
When the atoms of a dimer remain most of the time very far apart, in so-called long-range molecular states, their mutual interaction is ruled by plain atomic properties. The high-resolution spectroscopic study of some molecular excited states populated by photoassociation of cold atoms (photoassociative spectroscopy) gives a good illustration of this property. It provides accurate determinations of atomic radiative lifetimes, which are known to be sensitive tests for atomic calculations. A number of such analyses has been performed up to now, for all stable alkali atoms and for some other atom…
We study the effects of atomic beams harmonic vibrations of micro amplitudes and low frequencies on the mean atomic numbers of the detectors in atomic Mach-Zehnder interferometer, where the two atomic beams are in the same wave surface and have the same phases. We propose a vibrant factor F to quantitatively describe the effects of atomic beams vibrations. It shows that: (i)the vibrant factor F depends on the relative vibrant displacements and the initial phases rather than the absolute amplitudes, (ii)the factor F increases with the increase of the initial phases, and (iii)the frequencies can…
Atomic collisions are included in an interacting system of optical fields and trapped atoms allowing field amplification. We study the effects of collisions on the system stability. Also a study of the degree of entanglement between atomic and optical fields is made. We found that, for an atomic field initially in a vacuum state and optical field in a coherent state, the degree of entanglement does not depend on the optical field intensity or phase. We show that in conditions of exponential instability the system presents at long times two distinct stationary degree of entanglement with collis…
We report on design and construction of a Zeeman slower for strontium atoms which will be used in an optical atomic clock experiment. The paper describes briefly required specifications of the device, possible solutions, and concentrates on the chosen design. The magnetic field produced by the built Zeeman slower has been measured and compared with the simulations. The system consisting of an oven and Zeeman slower are designed to produce an atomic beam of 10-12 s-1 flux and final velocity of ~30 m/s.
We present a compact $^{87}$Rb atomic source for high precision dual atom interferometers. The source is based on a double-stage magneto-optical trap (MOT) design, consisting of a 2-dimensional (2D)-MOT for efficient loading of a 3D-MOT. The accumulated atoms are precisely launched in a horizontal moving molasses. Our setup generates a high atomic flux ($>10^{10}$ atoms/s) with precise and flexibly tunable atomic trajectories as required for high resolution Sagnac atom interferometry. We characterize the performance of the source with respect to the relevant parameters of the launched atoms, i…
Stabilizing important physical quantities to atom-based standards lies at the heart of modern atomic, molecular and optical physics, and is widely applied to the field of precision metrology. Of particular importance is the atom-based microwave field amplitude stabilizer, the so-called atomic candle. Previous atomic candles are realized with atoms in their ground state, and hence suffer from the lack of frequency band tunability and small stabilization bandwidth, severely limiting their development and potential applications. To tackle these limitations, we employ microwave-dressed Rydberg ato…
Fundamental atomic parameters, such as oscillator strengths, play a key role in modelling and understanding the chemical composition of stars in the universe. Despite the significant work underway to produce these parameters for many astrophysically important ions, uncertainties in these parameters remain large and can propagate throughout the entire field of astronomy. The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to provide the largest systematic and homogeneous quality assessment of atomic data to date in terms of wavelength, atomic and stellar parameter…
We present a wave atom optics theory of the Collective Atomic-Recoil Laser, where the atomic center-of-mass motion is treated quantum mechanically. It extends the previous ray atom optics theory, which treated the center-of-mass atomic motion classically, to the realm of ultracold atoms. For the case of a far off resonant pump laser we derive an analytical solution which gives the linear response of the CARL system for both the quantum and classical regimes. A linear stability analysis reveals significant qualitative differences between these two regimes, which arise from the effects of diffra…
We have developed an efficient approach for treating low-dimensional few-body processes in confined geometry of atomic and hybrid atom-ion traps. It based on the split-operator method in 2D discrete-variable representation (DVR) suggested by V. Melezhik for integration of the few-dimensional time-dependent Schrödinger equation. We give a brief review of the application to resonant ultracold atomic processes and discuss our latest results on hybrid atomic-ion systems. Prospects for the application of the method in other hot problems of the physics of low-dimensional few-particle systems are als…
We study the generation of atom vortex beams in the case where an atomic wave-packet, moving in free space, is diffracted from a properly tailored light mask with a spiral transverse profile. We show how such a diffraction scheme could lead to the production of an atomic Ferris wheel beam.
Approximate probabilities of formation of various atoms and ions in different bound states are determined for the exothermic nuclear $(n,{}^{6}$Li$;t,{}^{4}$He)-reaction of atomic lithium-6 with slow neutrons. In our calculations of the final state probabilities we have assumed that the incident lithium atom is in its ground (doublet) atomic ${}^2S(L = 0)-$state. It is straightforward to generalize our analysis to other bound states of the three-electron Li atom.
We describe here the Atomic bremsstrahlung - emission of continuous spectrum electromagnetic radiation, which is generated in collisions of particles that have internal deformable structure that includes positively and negatively charged constituents. The deformation of one of or both colliding partners induces multiple, mainly dipole, time-dependent electrical moments that become a source of radiation. The history of Atomic bremsstrahlung invention is presented and it's unusual in comparison to ordinary bremsstrahlung properties are discussed. As examples, fast electron - atom, non-relativist…
We show that gravitational wave detectors based on a type of atom interferometry are sensitive to ultralight scalar dark matter. Such dark matter can cause temporal oscillations in fundamental constants with a frequency set by the dark matter mass, and amplitude determined by the local dark matter density. The result is a modulation of atomic transition energies. This signal is ideally suited to a type of gravitational wave detector that compares two spatially separated atom interferometers referenced by a common laser. Such a detector can improve on current searches for electron-mass or elect…
We report on theoretical and numerical study of propagation of atomic beams crossing a detuned standing-wave laser beam in the geometric optics limit. The interplay between external and internal atomic degrees of freedom is used to manipulate the atomic motion along the optical axis by light. By adjusting the atom-laser detuning, we demonstrate how to focus, split and scatter atomic beams in a real experiment. The novel effect of chaotic scattering of atoms at a regular near-resonant standing wave is found numerically and explained qualitatively. Some applications of the effects found are disc…
On the basis of general theoretical results developed previously in [I. M. Sokolov et al., J. Exp. Theor. Phys. 112, 246 (2011)], we analyze spontaneous decay of a single atom inside cold atomic clouds under conditions when the averaged interatomic separation is less or comparable with the wavelength of quasi resonant radiation. Beyond the decay dynamics we analyze shifts of resonance as well as distortion of the spectral shape of the atomic transition.
A simple, approximate relation is found between the total energy of a free atom and its atomic number: E ~= -Z^{2.411}. The existence of this index is inherent in the Coulomb and many-body nature of the electron-electron interaction in the atomic system and cannot be fabricated from the existing fundamental physical constants.
We experimentally demonstrated that the stability of an atomic clock improves at fastest rate $τ^{-1}$ (where $τ$ is the averaging time) when the phase of a local oscillator is genuinely compared to the continuous phase of many atoms in a single trap (atomic phase lock). For this demonstration, we developed a simple method that repeatedly monitors the atomic phase while retaining its coherence by observing only a portion of the whole ion cloud. Using this new method, we measured the continuous phase over 3 measurement cycles, and thereby improved the stability scaling from $τ^{-1/2}$ to $τ^{-1…
