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:1804.04752 · Science

Building one molecule from a reservoir of two atoms

Lee R. Liu, Jonathan D. Hood, Yichao Yu, Jessie T. Zhang, Nicholas R. Hutzler, Till Rosenband, Kang-Kuen Ni

Published Apr 12, 2018• 225 citations
arXivHTMLPDF

Abstract

Chemical reactions typically proceed via stochastic encounters between reactants. Going beyond this paradigm, we combined exactly two atoms in a single, controlled reaction. The experimental apparatus traps two individual laser-cooled atoms [one sodium (Na) and one cesium (Cs)] in separate optical tweezers and then merges them into one optical dipole trap. Subsequently, photoassociation forms an excited-state NaCs molecule. The discovery of previously unseen resonances near the molecular dissociation threshold and measurement of collision rates are enabled by the tightly trapped ultracold sample of atoms. As laser-cooling and trapping capabilities are extended to more elements, the technique will enable the study of more diverse, and eventually more complex, molecules in an isolated environment, as well as synthesis of designer molecules for qubits.

DOI
10.1126/science.aar7797

Related papers

Building Single Molecules - Reactions, Collisions, and Spectroscopy of Two Atoms

Lee R. Liu

Recent theoretical and experimental advances have led to better understanding and control of simple molecules, bringing them to the forefront of quantum science. Diatomic polar molecules, with their vibrational and rotational degrees of freedom and electric dipole moment, are excellent candidates for a scalable qubit, probes of beyond-Standard Model physics, and quantum simulation of topological and chiral many-body systems. These applications call for high-phase space density (PSD) of molecules in a single quantum state. To date, the highest molecular PSD is achieved by coherently associating degenerate quantum gases of atoms into molecules. However, this requires fine-tuning of experimental parameters to maximize spatial overlap of the atomic density distributions while minimizing three-body recombination of the atoms.\nIn this thesis, we propose a bottom-up solution to gain single particle control of ultracold molecules for the first time. We use optical tweezers to deterministically assemble a single NaCs molecule in a single quantum state from a pair of Na and Cs atoms. Added benefits of using optical tweezers include: tight confinement of isolated atoms enabling cooling of Na and Cs to their quantum ground state of motion in less than 100~ms, and dynamic reconfigurability of optical tweezer arrays which will allow scaling up to defect-free arrays of single molecules. In the process, we realize a conceptually simple platform for studying atomic collisions and molecular spectra which derives its strength from the ability to gather "before" and "after" images of single atoms.

•May 21, 2019•1 citation

Ultracold Molecular Assembly

Lee R. Liu, Jessie T. Zhang, Yichao Yu +4 more

Chemical reactions can be surprisingly efficient at ultracold temperatures ( < 1mK) due to the wave nature of atoms and molecules. The study of reactions in the ultracold regime is a new research frontier enabled by cooling and trapping techniques developed in atomic and molecular physics. In addition, ultracold molecular gases that offer diverse molecular internal states and large electric dipolar interactions are sought after for studies of strongly interacting many-body quantum physics. Here we propose a new approach for producing ultracold molecules in the absolute internal and motional quantum ground state, where single molecules are assembled one by one from individual atoms. The scheme involves laser cooling, optical trapping, Raman sideband cooling, and coherent molecular state transfer. As a crucial initial step, we demonstrate quantum control of constituent atoms, including 3D ground-state cooling of a single Cs atom, in a simple apparatus. As laser technology advances to shorter wavelengths, additional atoms will be amenable to laser-cooling, allowing more diverse, and eventually more complex, molecules to be assembled with full quantum control.

arXiv:1701.03121•Jan 11, 2017•10 citations

Molecular Assembly of Ground-State Cooled Single Atoms

Lee R. Liu, Jonathan D. Hood, Yichao Yu +5 more

We demonstrate full quantum state control of two species of single atoms using optical tweezers and assemble the atoms into a molecule.Our demonstration includes 3D ground-state cooling of a single atom (Cs) in an optical tweezer, transport by several microns with minimal heating, and merging with a single Na atom.Subsequently, both atoms occupy the simultaneous motional ground state with 61(4)% probability.This realizes a sample of exactly two cotrapped atoms near the phase-space-density limit of one, and allows for efficient stimulated-Raman transfer of a pair of atoms into a molecular bound state of the triplet electronic ground potential a 3 Σ þ .The results are key steps toward coherent creation of single ultracold molecules for future exploration of quantum simulation and quantum information processing.

arXiv:1902.03935•Physical Review X•May 24, 2019•77 citations

CHEMISTRY IN THE ULTRACOLD REGIME: PRECISION MOLECULAR ASSEMBLY AND TEST OF STATISTICAL REACTION DYNAMICS

Kang-Kuen Ni

Advances in quantum manipulation of molecules bring unique opportunities, including the use of molecules to search for new physics, harnessing molecular resources for quantum engineering, and exploring chemical reactions in the ultra-low temperature regime. In this talk, I will focus on the latter two topics. First, I will introduce our effort on building single ultracold molecules with full internal and motional state control in optical tweezers for future quantum simulators and computers. This work allows us to go beyond the usual paradigm of chemical reactions that proceed via stochastic encounters between reactants, to a single, controlled reaction of exactly two atoms. Second, I will present our work giving a detailed microscopic picture of molecules transforming from one species to another. We develop full quantum state mapping of chemical reaction product-pairs from single events, which we use to precisely benchmark statistical theory.

International Symposium on Molecular Spectroscopy (ISMS)•Jun 20, 2022•0 citations

Preparation of one 87Rb and one 133Cs atom in a single optical tweezer

R V Brooks, S Spence, A Guttridge +5 more

Abstract We report the preparation of exactly one 87Rb atom and one 133Cs atom in the same optical tweezer as the essential first step towards the construction of a tweezer array of individually trapped 87Rb133Cs molecules. Through careful selection of the tweezer wavelengths, we show how to engineer species-selective trapping potentials suitable for high-fidelity preparation of Rb + Cs atom pairs. Using a wavelength of 814 nm to trap Rb and 938 nm to trap Cs, we achieve loading probabilities of 0.508(6) for Rb and 0.547(6) for Cs using standard red-detuned molasses cooling. Loading the traps sequentially yields exactly one Rb and one Cs atom in 28.4(6)% of experimental runs. Using a combination of an acousto-optic deflector and a piezo-controlled mirror to control the relative position of the tweezers, we merge the two tweezers, retaining the atom pair with a probability of 0.9 9 ( − 0.02 ) ( + 0.01 ) . We use this capability to study hyperfine-state-dependent collisions of Rb and Cs in the combined tweezer and compare the measured two-body loss rates with coupled-channel quantum scattering calculations.

arXiv:2104.05760•New Journal of Physics•May 11, 2021•25 citations

Cold Molecules, Photoassociation, Optical Pumping and Laser Cooling: The Cesium Case

Bentham Science Publisher Bentham Science Publisher

The cold-molecule field concerns the physics and the applications of molecular systems with translational temperature well below the 1 К range. The possibility of controlling all the motion as well as the internal quantum state of a sample of molecules is a long-term goal that opens the possibility for many new experiments and measurements ranging from fundamental constants to quantum chemistry and quantum computation. Although, direct laser cooling of the translational degree of freedom of molecules is still waiting for further technological or theoretical breakthroughs and ideas, many different techniques have proven to be successful in producing different types of cold as well as ultracold (i.e. T < 1 mK) molecules. In this chapter, we will concentrate on the description of one of these techniques: the photoassociation of laser cooled atoms. We will report on the status of the art of this technique for the case of cesium atoms, describing all the main experimental findings. In particular, we will illustrate the different photoassociation schemes for molecule formation, the detection schemes through photoionization, the molecule trapping in a magnetic or dipolar trap, the vibrational cooling into a single vibrational state and finally the present prospects for rotational cooling.

BENTHAM SCIENCE PUBLISHERS eBooks•Mar 13, 2012•0 citations
Chemical reactions typically proceed via stochastic encounters between reactants. Going beyond this paradigm, we combined exactly two atoms in a single, controlled reaction. The experimental apparatus traps two individual laser-cooled atoms [one sodium (Na) and one cesium (Cs)] in separate optical tweezers and then merges them into one optical dipole trap. Subsequently, photoassociation forms an excited-state NaCs molecule. The discovery of previously unseen resonances near the molecular dissociation threshold and measurement of collision rates are enabled by the tightly trapped ultracold sample of atoms. As laser-cooling and trapping capabilities are extended to more elements, the technique will enable the study of more diverse, and eventually more complex, molecules in an isolated environment, as well as synthesis of designer molecules for qubits.
Recent theoretical and experimental advances have led to better understanding and control of simple molecules, bringing them to the forefront of quantum science. Diatomic polar molecules, with their vibrational and rotational degrees of freedom and electric dipole moment, are excellent candidates for a scalable qubit, probes of beyond-Standard Model physics, and quantum simulation of topological and chiral many-body systems. These applications call for high-phase space density (PSD) of molecules in a single quantum state. To date, the highest molecular PSD is achieved by coherently associating degenerate quantum gases of atoms into molecules. However, this requires fine-tuning of experimental parameters to maximize spatial overlap of the atomic density distributions while minimizing three-body recombination of the atoms.\nIn this thesis, we propose a bottom-up solution to gain single particle control of ultracold molecules for the first time. We use optical tweezers to deterministically assemble a single NaCs molecule in a single quantum state from a pair of Na and Cs atoms. Added benefits of using optical tweezers include: tight confinement of isolated atoms enabling cooling of Na and Cs to their quantum ground state of motion in less than 100~ms, and dynamic reconfigurability of optical tweezer arrays which will allow scaling up to defect-free arrays of single molecules. In the process, we realize a conceptually simple platform for studying atomic collisions and molecular spectra which derives its strength from the ability to gather "before" and "after" images of single atoms.
Chemical reactions can be surprisingly efficient at ultracold temperatures ( < 1mK) due to the wave nature of atoms and molecules. The study of reactions in the ultracold regime is a new research frontier enabled by cooling and trapping techniques developed in atomic and molecular physics. In addition, ultracold molecular gases that offer diverse molecular internal states and large electric dipolar interactions are sought after for studies of strongly interacting many-body quantum physics. Here we propose a new approach for producing ultracold molecules in the absolute internal and motional quantum ground state, where single molecules are assembled one by one from individual atoms. The scheme involves laser cooling, optical trapping, Raman sideband cooling, and coherent molecular state transfer. As a crucial initial step, we demonstrate quantum control of constituent atoms, including 3D ground-state cooling of a single Cs atom, in a simple apparatus. As laser technology advances to shorter wavelengths, additional atoms will be amenable to laser-cooling, allowing more diverse, and eventually more complex, molecules to be assembled with full quantum control.
We demonstrate full quantum state control of two species of single atoms using optical tweezers and assemble the atoms into a molecule.Our demonstration includes 3D ground-state cooling of a single atom (Cs) in an optical tweezer, transport by several microns with minimal heating, and merging with a single Na atom.Subsequently, both atoms occupy the simultaneous motional ground state with 61(4)% probability.This realizes a sample of exactly two cotrapped atoms near the phase-space-density limit of one, and allows for efficient stimulated-Raman transfer of a pair of atoms into a molecular bound state of the triplet electronic ground potential a 3 Σ þ .The results are key steps toward coherent creation of single ultracold molecules for future exploration of quantum simulation and quantum information processing.
Advances in quantum manipulation of molecules bring unique opportunities, including the use of molecules to search for new physics, harnessing molecular resources for quantum engineering, and exploring chemical reactions in the ultra-low temperature regime. In this talk, I will focus on the latter two topics. First, I will introduce our effort on building single ultracold molecules with full internal and motional state control in optical tweezers for future quantum simulators and computers. This work allows us to go beyond the usual paradigm of chemical reactions that proceed via stochastic encounters between reactants, to a single, controlled reaction of exactly two atoms. Second, I will present our work giving a detailed microscopic picture of molecules transforming from one species to another. We develop full quantum state mapping of chemical reaction product-pairs from single events, which we use to precisely benchmark statistical theory.
Abstract We report the preparation of exactly one 87Rb atom and one 133Cs atom in the same optical tweezer as the essential first step towards the construction of a tweezer array of individually trapped 87Rb133Cs molecules. Through careful selection of the tweezer wavelengths, we show how to engineer species-selective trapping potentials suitable for high-fidelity preparation of Rb + Cs atom pairs. Using a wavelength of 814 nm to trap Rb and 938 nm to trap Cs, we achieve loading probabilities of 0.508(6) for Rb and 0.547(6) for Cs using standard red-detuned molasses cooling. Loading the traps sequentially yields exactly one Rb and one Cs atom in 28.4(6)% of experimental runs. Using a combination of an acousto-optic deflector and a piezo-controlled mirror to control the relative position of the tweezers, we merge the two tweezers, retaining the atom pair with a probability of 0.9 9 ( − 0.02 ) ( + 0.01 ) . We use this capability to study hyperfine-state-dependent collisions of Rb and Cs in the combined tweezer and compare the measured two-body loss rates with coupled-channel quantum scattering calculations.
The cold-molecule field concerns the physics and the applications of molecular systems with translational temperature well below the 1 К range. The possibility of controlling all the motion as well as the internal quantum state of a sample of molecules is a long-term goal that opens the possibility for many new experiments and measurements ranging from fundamental constants to quantum chemistry and quantum computation. Although, direct laser cooling of the translational degree of freedom of molecules is still waiting for further technological or theoretical breakthroughs and ideas, many different techniques have proven to be successful in producing different types of cold as well as ultracold (i.e. T < 1 mK) molecules. In this chapter, we will concentrate on the description of one of these techniques: the photoassociation of laser cooled atoms. We will report on the status of the art of this technique for the case of cesium atoms, describing all the main experimental findings. In particular, we will illustrate the different photoassociation schemes for molecule formation, the detection schemes through photoionization, the molecule trapping in a magnetic or dipolar trap, the vibrational cooling into a single vibrational state and finally the present prospects for rotational cooling.