Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1912.08104

Prospects for single photon sideband cooling in fermionic Lithium

Federico Berto, Carlo Sias

Published Dec 14, 2019• 1 citation
arXivHTMLPDF

Abstract

We present an analytic and numerical study for realizing single photon sideband cooling in an ultracold sample of fermionic Lithium trapped in a periodic optical potential. We develop an analytical model and obtain a master equation for the bound level populations. The cooling sequence is simulated both with a laser at a fixed frequency and with a frequency sweep. Finally, a Monte Carlo simulation is performed taking into account the full hyperfine spectrum of $^6\!$Li. We find that a gas of $^6\!$Li atoms loaded from a Magneto-Optical trap into a deep optical lattice can be cooled down to a $99\%$ occupancy of the lattice ground state after a 5mm single photon sideband cooling using the D1 line of Li.

DOI
10.48550/arxiv.1912.08104

Related papers

Prospects for single-photon sideband cooling of optically trapped neutral atoms

Federico Berto, Elia Perego, Lucia Duca +1 more

We propose a cooling scheme for realizing single-photon sideband cooling on particles trapped in a statedependent optical potential.We develop a master rate equation from an ab initio model and find that in experimentally feasible conditions it is possible to reduce the average occupation number of the vibrational levels in one dimension by more than 90% by applying a frequency sweep on the cooling laser that sequentially cools all the motional states.Notably, this cooling scheme works also when a particle experiences a deeper trap in its internal ground state than in its excited state, a condition for which conventional single-photon sideband cooling does not work.In our analysis, we consider two cases: a two-level particle confined in an optical tweezer, and Li atoms confined in an optical lattice, and we find conditions for efficient cooling in both cases.The results from the model are confirmed by a full quantum Monte Carlo simulation of the system Hamiltonian.Our findings provide an alternative cooling scheme that can be applied in principle to any particle, e.g., atoms, molecules, or ions, confined in a state-dependent optical potential.

arXiv:2107.04110•Physical Review Research•Nov 11, 2021•5 citations

Enhanced trapping of colding lithium by using the multiple-sideband cooling in a two-dimensional magneto-optical trap

Kai Li, Dongfang Zhang, Tianyou Gao +2 more

Trapping lithium with a big number in a simplified experimental setup has difficulties and challenges today. In this paper, we experimentally demonstrate the enhancement of \textsuperscript{6}Li trapping efficiency in a three-dimensional magneto-optical trap (3D MOT) by using the multiple-sideband cooling in a two-dimensional magneto-optical trap (2D MOT). To improve the number of trapped atoms, we broaden the cooling light spectrum to 102 MHz composed of seven frequency components and then trap atoms with a number of $6.0\times10^8$ which is about 4 times compared to that in the single-frequency cooling. The capture velocity and dependence of atomic number on the laser detuning have been analyzed, where the experimental result has a good agreement with the theoretical prediction based on a simple two-level model. We also analyze the loss rate of alkali metals due to fine-structure exchanging collisions and find that the multiple-sideband cooling is special valid for lithium.

arXiv:1505.03591•May 14, 2015•0 citations

Enhanced trapping of cold Li6 using multiple-sideband cooling in a two-dimensional magneto-optical trap

Kai Li, Dongfang Zhang, Tianyou Gao +2 more

Trapping a large number of $^{6}\mathrm{Li}$ atoms in a simplified experimental setup is a long-term pursuit in the studies of degenerate Fermi gases. We experimentally and theoretically demonstrate the enhancement of $^{6}\mathrm{Li}$ trapping efficiency in a three-dimensional magneto-optical trap (3D MOT) by using the multiple-sideband cooling in a two-dimensional magneto-optical trap (2D MOT). In the 2D MOT, we increase the spectral width of the cooling light to 102 MHz by generating six frequency sidebands in order to couple fast atoms. The capture velocity is dramatically increased by employing the multiple-sideband cooling. The number of trapped atoms in the 3D MOT is $6.0\ifmmode\times\else\texttimes\fi{}{10}^{8}$, which is higher by a factor of 4 than in the case of single-frequency cooling. We have investigated the dependence of atom number on laser detuning, and our experimental result agrees well with the prediction of a simple two-level model. The efficiency of the multiple-sideband cooling for lithium (in contrast to many other alkali-metal atoms) is also confirmed by the analysis of the loss due to fine-structure changing collisions.

Physical Review A•Jul 22, 2015•11 citations

Semi-classical and quantum Monte Carlo simulations in optical lattices

Stephen Peter Winklbauer

This thesis gives an account of work done on semi-classical and quantum Monte Carlo simulations in far-detuned optical lattices. Firstly, the basic principles of laser cooling of atoms are presented including a short introduction to optical lattices in the near and far-detuned regime. A detailed analysis is made of the band-structure of optical lattices, using the Bloch formalism, and of the bound-state population distribution appropriate for a thermal sample of trapped atoms. Secondly, a general overview is given of the quantum Monte Carlo method for simulating the dynamics of atom-light interactions. This is followed by a detailed study of the concept of Raman cooling, which is a useful tool to prepare atoms in the ground motional state of the lattice and an important first step to achieving quantum state control with ultra-cold atoms. A simplified model of Raman cooling is introduced and simulated using the quantum Monte Carlo wave-function approach. Then the implementation of simulations of resolved-sideband Raman cooling based on this model is discussed as is how the results were used to optimize the experimental work done by our group. The results of these simulations show for the first time that the quantum Zeno effect has a crucial impact on the efficiency of Raman cooling experiments. Also the experimental measurements of the temperature of Raman sideband cooled atoms for a range of parameters are compared with theoretical results and shows a good qualitative agreement. Thirdly, the results of semi-classical numerical simulations of parametric excitation in optical lattices are presented. It is shown that the modulation of the potential can result in selective parametric excitation of trapped atoms. The theoretical results show good qualitative agreement with experiment. The thesis is concluded with a description of possible avenues for future studies on quantum state control in optical lattices.

•Jan 1, 2004•0 citations

Simultaneous sub-Doppler laser cooling of fermionic Li6 and K40 on the D1 line: Theory and experiment

Franz Sievers, Norman Kretzschmar, Diogo Fernandes +7 more

We report on simultaneous sub-Doppler laser cooling of fermionic $^{6}\mathrm{Li}$ and $^{40}\mathrm{K}$ using the ${D}_{1}$ optical transitions. We compare experimental results to a numerical simulation of the cooling process applying a semiclassical Monte Carlo wave-function method. The simulation takes into account the three-dimensional optical molasses setup and the dipole interaction between atoms and the bichromatic light field driving the ${D}_{1}$ transitions. We discuss the physical mechanisms at play, identify the important role of coherences between the ground-state hyperfine levels, and compare ${D}_{1}$ and ${D}_{2}$ sub-Doppler cooling. In 5 ms, the ${D}_{1}$ molasses phase greatly reduces the temperature for both $^{6}\mathrm{Li}$ and $^{40}\mathrm{K}$ at the same time, with final temperatures of 44 and $11\ensuremath{\mu}\mathrm{K}$, respectively. For both species this leads to a phase-space density close to ${10}^{\ensuremath{-}4}$. These conditions are well suited to direct loading of an optical or magnetic trap for efficient evaporative cooling to quantum degeneracy.

arXiv:1410.8545•Physical Review A•Feb 23, 2015•54 citations

A versatile apparatus for fermionic lithium quantum gases based on an interference-filter laser system

Benjamin Gänger, Jan Phieler, Benjamin Nagler +1 more

We report on the design and construction of a versatile setup for experiments with ultracold lithium (Li) gases. We discuss our methods to prepare an atomic beam and laser cool it in a Zeeman slower and a subsequent magneto-optical trap, which rely on established methods. We focus on our laser system based on a stable interference-filter-stabilized, linear-extended-cavity diode laser, so far unreported for lithium wavelengths. Moreover, we describe our optical setup to combine various laser frequencies for cooling, manipulation, and detection of Li atoms. We characterize the performance of our system preparing degenerate samples of Li atoms via forced evaporation in a hybrid crossed-beam optical-dipole trap plus confining magnetic trap. Our apparatus allows one to produce quantum gases of N ≈ 105…106 fermionic lithium-6 atoms at nanokelvin temperatures in cycle times below 10 s. Our optical system is particularly suited to study the dynamics of fermionic superfluids in engineered optical potentials.

Review of Scientific Instruments•Sep 1, 2018•16 citations
We present an analytic and numerical study for realizing single photon sideband cooling in an ultracold sample of fermionic Lithium trapped in a periodic optical potential. We develop an analytical model and obtain a master equation for the bound level populations. The cooling sequence is simulated both with a laser at a fixed frequency and with a frequency sweep. Finally, a Monte Carlo simulation is performed taking into account the full hyperfine spectrum of 6 ⁣^6\!6Li. We find that a gas of 6 ⁣^6\!6Li atoms loaded from a Magneto-Optical trap into a deep optical lattice can be cooled down to a 99%99\%99% occupancy of the lattice ground state after a 5mm single photon sideband cooling using the D1 line of Li.
We propose a cooling scheme for realizing single-photon sideband cooling on particles trapped in a statedependent optical potential.We develop a master rate equation from an ab initio model and find that in experimentally feasible conditions it is possible to reduce the average occupation number of the vibrational levels in one dimension by more than 90% by applying a frequency sweep on the cooling laser that sequentially cools all the motional states.Notably, this cooling scheme works also when a particle experiences a deeper trap in its internal ground state than in its excited state, a condition for which conventional single-photon sideband cooling does not work.In our analysis, we consider two cases: a two-level particle confined in an optical tweezer, and Li atoms confined in an optical lattice, and we find conditions for efficient cooling in both cases.The results from the model are confirmed by a full quantum Monte Carlo simulation of the system Hamiltonian.Our findings provide an alternative cooling scheme that can be applied in principle to any particle, e.g., atoms, molecules, or ions, confined in a state-dependent optical potential.
Trapping lithium with a big number in a simplified experimental setup has difficulties and challenges today. In this paper, we experimentally demonstrate the enhancement of \textsuperscript{6}Li trapping efficiency in a three-dimensional magneto-optical trap (3D MOT) by using the multiple-sideband cooling in a two-dimensional magneto-optical trap (2D MOT). To improve the number of trapped atoms, we broaden the cooling light spectrum to 102 MHz composed of seven frequency components and then trap atoms with a number of 6.0×1086.0\times10^86.0×108 which is about 4 times compared to that in the single-frequency cooling. The capture velocity and dependence of atomic number on the laser detuning have been analyzed, where the experimental result has a good agreement with the theoretical prediction based on a simple two-level model. We also analyze the loss rate of alkali metals due to fine-structure exchanging collisions and find that the multiple-sideband cooling is special valid for lithium.
Trapping a large number of 6Li^{6}\mathrm{Li}6Li atoms in a simplified experimental setup is a long-term pursuit in the studies of degenerate Fermi gases. We experimentally and theoretically demonstrate the enhancement of 6Li^{6}\mathrm{Li}6Li trapping efficiency in a three-dimensional magneto-optical trap (3D MOT) by using the multiple-sideband cooling in a two-dimensional magneto-optical trap (2D MOT). In the 2D MOT, we increase the spectral width of the cooling light to 102 MHz by generating six frequency sidebands in order to couple fast atoms. The capture velocity is dramatically increased by employing the multiple-sideband cooling. The number of trapped atoms in the 3D MOT is $6.0\ifmmode\times\else\texttimes\fi{}{10}^{8}$, which is higher by a factor of 4 than in the case of single-frequency cooling. We have investigated the dependence of atom number on laser detuning, and our experimental result agrees well with the prediction of a simple two-level model. The efficiency of the multiple-sideband cooling for lithium (in contrast to many other alkali-metal atoms) is also confirmed by the analysis of the loss due to fine-structure changing collisions.
This thesis gives an account of work done on semi-classical and quantum Monte Carlo simulations in far-detuned optical lattices. Firstly, the basic principles of laser cooling of atoms are presented including a short introduction to optical lattices in the near and far-detuned regime. A detailed analysis is made of the band-structure of optical lattices, using the Bloch formalism, and of the bound-state population distribution appropriate for a thermal sample of trapped atoms. Secondly, a general overview is given of the quantum Monte Carlo method for simulating the dynamics of atom-light interactions. This is followed by a detailed study of the concept of Raman cooling, which is a useful tool to prepare atoms in the ground motional state of the lattice and an important first step to achieving quantum state control with ultra-cold atoms. A simplified model of Raman cooling is introduced and simulated using the quantum Monte Carlo wave-function approach. Then the implementation of simulations of resolved-sideband Raman cooling based on this model is discussed as is how the results were used to optimize the experimental work done by our group. The results of these simulations show for the first time that the quantum Zeno effect has a crucial impact on the efficiency of Raman cooling experiments. Also the experimental measurements of the temperature of Raman sideband cooled atoms for a range of parameters are compared with theoretical results and shows a good qualitative agreement. Thirdly, the results of semi-classical numerical simulations of parametric excitation in optical lattices are presented. It is shown that the modulation of the potential can result in selective parametric excitation of trapped atoms. The theoretical results show good qualitative agreement with experiment. The thesis is concluded with a description of possible avenues for future studies on quantum state control in optical lattices.
We report on simultaneous sub-Doppler laser cooling of fermionic 6Li^{6}\mathrm{Li}6Li and 40K^{40}\mathrm{K}40K using the D1{D}_{1}D1​ optical transitions. We compare experimental results to a numerical simulation of the cooling process applying a semiclassical Monte Carlo wave-function method. The simulation takes into account the three-dimensional optical molasses setup and the dipole interaction between atoms and the bichromatic light field driving the D1{D}_{1}D1​ transitions. We discuss the physical mechanisms at play, identify the important role of coherences between the ground-state hyperfine levels, and compare D1{D}_{1}D1​ and D2{D}_{2}D2​ sub-Doppler cooling. In 5 ms, the D1{D}_{1}D1​ molasses phase greatly reduces the temperature for both 6Li^{6}\mathrm{Li}6Li and 40K^{40}\mathrm{K}40K at the same time, with final temperatures of 44 and $11\ensuremath{\mu}\mathrm{K}$, respectively. For both species this leads to a phase-space density close to ${10}^{\ensuremath{-}4}$. These conditions are well suited to direct loading of an optical or magnetic trap for efficient evaporative cooling to quantum degeneracy.
We report on the design and construction of a versatile setup for experiments with ultracold lithium (Li) gases. We discuss our methods to prepare an atomic beam and laser cool it in a Zeeman slower and a subsequent magneto-optical trap, which rely on established methods. We focus on our laser system based on a stable interference-filter-stabilized, linear-extended-cavity diode laser, so far unreported for lithium wavelengths. Moreover, we describe our optical setup to combine various laser frequencies for cooling, manipulation, and detection of Li atoms. We characterize the performance of our system preparing degenerate samples of Li atoms via forced evaporation in a hybrid crossed-beam optical-dipole trap plus confining magnetic trap. Our apparatus allows one to produce quantum gases of N ≈ 105…106 fermionic lithium-6 atoms at nanokelvin temperatures in cycle times below 10 s. Our optical system is particularly suited to study the dynamics of fermionic superfluids in engineered optical potentials.