Deceleration Of Atoms Research Articles

Compact magneto-optical trap of thulium atoms for a transportable optical clock.

We have developed a compact vacuum system for laser cooling and spectroscopy of neutral thulium atoms. Compactness is achieved by obviating a classical Zeeman slower section and placing an atomic oven close to a magneto-optical trap (MOT), specifically at the distance of 11 cm. In this configuration, we significantly gained in solid angle of an atomic beam, which is affected by MOT laser beams, and reached 1 million atoms loaded directly in the MOT with only 15 mW of MOT cooling beams net power. By exploiting Zeeman-like deceleration of atoms with an additional laser beam and tailoring the MOT magnetic field gradient with a small magnetic coil, we demonstrated trapping of up to 13 million atoms. These results show great perspective of the developed setup for realizing a compact high-performance optical atomic clock based on thulium atoms.

Hydrodynamics of an Earthquake Swarm

The foundation of the material described in the article is the property of a liquid during movement along the pipeline to create a hydraulic shock. Channels, faults, and cracks in the earth's crust can be attributed to underground “pipelines”, and magma to liquid. Consequently, when magma moves in the earth's crust and mantle, hydraulic shocks occur. The shock waves that arise during this process form energy pulses, which are accompanied by instantaneous changes in temperature, pressure, acceleration, and deceleration of atoms, phase transitions of matter and a swarm of earthquakes. Being within the framework of Mr. Reid's theory - Elastic recoil, it is impossible to answer the question of the formation of an earthquake swarm, and modern geophysics indecisively blames magma for this, which supposedly changes the temperature background of the earth's crust, thereby causing volumetric expansion of rocks and tremors. We find this explanation correct, but insufficient. In our opinion, the mechanism of the formation of an earthquake swarm is the energy of hydraulic shocks of magma during its movement in faults and fissures of rocks.

Simultaneous deceleration of atoms and molecules in a supersonic beam

A unique property of Zeeman effect based manipulation of paramagnetic particle’s motion is the ability to control velocities of both atoms and molecules. In particular the moving magnetic trap decelerator is capable of slowing and eventually trapping mixtures of both cold atoms and cold molecules generated in a supersonic expansion. Here we report the deceleration of molecular oxygen together with metastable argon atoms. The cold mixture with temperature below 1 K is slowed from an initial velocity of 430 m s−1 down to 100 m s−1. Our decelerator spans 2.4 m and consists of 480 quadrupole traps. Our results pave the way for the study of sympathetic cooling of molecules by laser cooled atoms.

How to Combine Binary Collision Approximation and Multi-Body Potential for Molecular Dynamics

Our group has been developing a hybrid simulation of the molecular dynamics (MD) and the binary collision approximation (BCA) simulation. One of the main problems of this hybridization model is that the multi-body potential suddenly appears at the moment when the simulation method switches from the BCA to the MD. This instantaneously emerged multi-body potential causes the acceleration or deceleration of atoms of the system. To solve this problem, the kinetic energy of atoms should be corrected to conserve the total energy in the system. This paper gives the solution. The hybrid simulation for hydrogen atom injection into a graphite material is executed in order to demonstrate the solution.

Deceleration of atoms in an n-photon process by means of a laser-travelling wave in the Dirac representation

A detailed theoretical study is made of the slowing down of the atomic beam by resonant laser radiation. By using the density matrix technique in the interaction representation, employing optical Bloch equations, one can obtain the average radiation force, with respect to the coherent state of the laser mode, represented in the complex plane. It is revealed that all the relevant variables are explicit functions of time via the average photon number. It is shown under the conditions which can be attained in practice that the behavior of the velocity and diffusion coefficients in both the longitudinal and transverse directions is consistent with previous works on such phenomenon.

The Effect of a Fluctuating Laser Field on the Process of Decelerating Atoms in the Zeeman Tuning Technique

Abstract We present a study on the process of atomic deceleration in the Zeeman tuning technique when a fluctuating laser is used. The characterization of the deceleration is made through the analysis of velocity trajectories (k v(z)) from integration of the averaged equation of motion obtained from the Bloch optical equations. Atomic motion described from an accelerated frame of reference aids the analysis of the process. It is shown that the capability of an atom to follow a magnetic field profile is more sensitive to amplitude than to phase fluctuations. The analysis presented here permits evaluation of laser quality beam on optical deceleration of atoms.

The Dicke Effect in Nonlinear Spectroscopy

Abstract It is shown that deceleration of atoms by the dynamic force of friction leads to a narrowing of Voigt's contour in linear spectroscopy and to the Bennett hole being shifted, narrowed and asymmetric in nonlinear spectroscopy. Estimates are presented for the argon-ion laser plasma, where the friction force is to be taken into account in precise calculation.

Adiabatic following conditions for the deceleration of atoms with the Zeeman tuning technique

We present a study of the decelaration of atoms with the Zeeman tuning technique which allows us to investigate the conditions for the adiabatic following of atoms in an inhomogeneous magnetic field. The atomic motion is described in an accelerated frame of reference and two possible solutions are found for the atomic velocity, one being stable and the other unstable. The stability condition for the velocity imposes an upper limit for the magnetic field gradient and experimental results for this limit are presented.

Laser Deceleration of an Atomic Beam

Deceleration and velocity bunching of Na atoms in an atomic beam have been observed. The deceleration, caused by absorption of counterpropagating resonant laser light, amounts to 40% of the initial thermal velocity, corresponding to about 15 000 absorptions. Atoms were kept in resonance with the laser by using a spatially varying magnetic field to provide a changing Zeeman shift to compensate for the changing Doppler shift as the atoms decelerated.

Hydrodynamical equations for atomic motion in a resonant light wave

The hydrodynamical equations for atomic motion in a resonant light wave have been derived. The obtained equations are applied to analyze the atomic deceleration in counter propagating light beam.