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:2210.10859 · Physical Review A

Zeeman-Sisyphus deceleration for heavy molecules with perturbed excited-state structure

Hiromitsu Sawaoka, Alexander Frenett, Abdullah Nasir, Tasuku Ono, Benjamin L. Augenbraun, Timothy C. Steimle, John M. Doyle

Published Feb 15, 2023• 7 citations
arXivHTMLPDF

Abstract

We demonstrate and characterize Zeeman-Sisyphus (ZS) deceleration of a beam of ytterbium monohydroxide. Our method uses a combination of large magnetic fields ($\ensuremath{\sim}2.5$ T) and optical spin-flip transitions to decelerate molecules while scattering only $\ensuremath{\sim}10$ photons per molecule. We study the challenges associated with the presence of internal molecular perturbations among the excited electronic states and discuss the methods used to overcome these challenges, including a modified ZS decelerator using microwave and optical transitions.

DOI
10.1103/physreva.107.022810

Related papers

Zeeman-Sisyphus Deceleration of Molecular Beams

Benjamin L. Augenbraun, Alexander Frenett, Hiromitsu Sawaoka +5 more

We present a robust, continuous molecular decelerator that employs high magnetic fields and few optical pumping steps. CaOH molecules are slowed, accumulating at low velocities in a range sufficient for loading both magnetic and magneto-optical traps. During the slowing, the molecules scatter only seven photons, removing around 8 K of energy. Because large energies can be removed with only a few spontaneous radiative decays, this method can in principle be applied to nearly any paramagnetic atomic or molecular species, opening a general path to trapping of complex molecules.

arXiv:2109.03067•Physical Review Letters•Dec 20, 2021•21 citations

Laser cooling, optical trapping and Zeeman-Sisyphus deceleration of heavy polyatomic molecules for probing physics beyond the Standard Model

Hiromitsu Sawaoka

Ultracold polyatomic molecules containing heavy nuclei, such as SrOH and YbOH, are sensitive to T- symmetry violating and P-symmetry violating physics beyond the Standard Model through the electron’s electric dipole moment. Furthermore, SrOH is sensitive to ultralight Dark Matter through measuring time variations of fundamental constants. However, in order to make full use of these molecules, they need to be cooled to ultracold temperatures and held in optical traps. We have realized a magneto-optical trap (MOT) of SrOH and used this as the essential element to achieve optical trap- ping in the microKelvin temperature regime. We observed MOT lifetimes approaching 200 ms with temperatures ∼ 1 mK and observed damped oscillations in the MOT. We further cooled the SrOH molecules to ∼ 40 μ K using Λ-enhanced gray molasses, and compressed the cloud to about 100 μm size using the conveyor belt MOT technique. Using this ultracold dense cloud of SrOH, we loaded an optical dipole trap (ODT), with a molecular lifetime of 1.2(1) seconds. In separate experiments with YbOH, which is heavier than SrOH, we demonstrated a novel deceleration method (Zeeman- Sisyphus deceleration) that can slow YbOH to under 20 m/s with only a few photons scattered utilizing high magnetic fields up to 2.5 T. By driving spin-flip transitions at the maxima and minima of the magnetic fields, slowing was achieved, which is a critical first step toward loading of a MOT for this species. We addressed the challenges associated with driving spin-flip transitions in molecules that have molecular perturbations among the electronic excited states and developed an understanding of the physics of such systems that is applicable to a wide range of molecules.

•Jan 1, 2025•0 citations

Principles and Design of a Zeeman–Sisyphus Decelerator for Molecular Beams

Noah J. Fitch, Michael R. Tarbutt

We explore a technique for decelerating molecules using a static magnetic field and optical pumping. Molecules travel through a spatially varying magnetic field and are repeatedly pumped into a weak-field seeking state as they move towards each strong field region, and into a strong-field seeking state as they move towards weak field. The method is time-independent and so is suitable for decelerating both pulsed and continuous molecular beams. By using guiding magnets at each weak field region, the beam can be simultaneously guided and decelerated. By tapering the magnetic field strength in the strong field regions, and exploiting the Doppler shift, the velocity distribution can be compressed during deceleration. We develop the principles of this deceleration technique, provide a realistic design, use numerical simulations to evaluate its performance for a beam of CaF, and compare this performance to other deceleration methods.

arXiv:1609.05823•ChemPhysChem•Sep 15, 2016•32 citations

Ring-shaped traveling wave Zeeman decelerator for both light and heavy molecules

Yabing Ji, Qing Liu, Yang Liu +3 more

Abstract Taming more species of molecules with large density is a long-standing goal in molecular science. Heavy molecule (> 100 amu) is of particular interest for precision measurements. However, decelerating a fast-moving beam of heavy molecules to rest remains challenging for Zeeman deceleration. Additionally, the traditional approach of pulsed Zeeman decelerator suffers from serious molecular loss during deceleration, significantly limiting its potential applications. Herein, we present a ring-shaped traveling wave Zeeman decelerator (RTWZD) featured with true three-dimensional smoothly-moving magnetic potential wells that directly solve the above intractable problems. With this approach, not only the density of the molecule can be greatly increased but also the range of molecular species for Zeeman deceleration can be extended from light to heavy. The performance of the RTWZD is characterized with both the theoretical analysis and the numerical calculation, where a group of atoms and molecules such as 7Li, 32O2, 88Sr19F and 174Yb19F are employed as testers. Losses in the traditional Zeeman decelerator can be avoided, yielding more than two orders of magnitude improvement in molecular density. These characteristics of the RTWZD make it an ideal toolbox to produce cold and dense atomic/molecular samples, enabling promising prospects for cold collision, sympathetic cooling, and precision measurement.

•Jan 30, 2023•0 citations

Motional Control of Polyatomic Molecules for Precision Measurement

Alexander Frenett

Extending AMO techniques of motional control to heavy polyatomic molecules opens new possibilities for precision measurements of fundamental physics. Though various laser-cooling and deceleration techniques have been applied to diatomic molecules throughout the last decade, their application to more complex molecules has heretofore been focused on light species, leaving generalizability to heavy species an open question. To investigate the high-mass frontier, we here study how to extend motional control to heavy-atom-containing polyatomic molecules. First, we discuss Zeeman-Sisyphus deceleration of YbOH, which can be used to decelerate species capable of scattering only ~10s of photons. Then, we discuss radiative slowing and magneto-optical trapping of SrOH, techniques only extendable to species capable of scattering $\sim10^4$ photons. The last work focuses on spectroscopy of nonlinear molecules to assess the viability of extending techniques of motional control to more complex species. We find a dependence of both rotational and vibrational control on symmetry group, and identify a next-generation candidate for laser cooling. We end with a overview tying these projects together, and assessing the future of motional control along mass and complexity axes, including brief suggestions of how complementary methods to those studied here can further expand into the frontiers of molecular control.

•Jan 1, 2024•0 citations

Design and construction of a multistage Zeeman decelerator for crossed molecular beams scattering experiments

Theo Cremers, Niek Janssen, Edwin Sweers +1 more

Zeeman deceleration is a relatively new technique used to obtain full control over the velocity of paramagnetic atoms or molecules in a molecular beam. We present a detailed description of a multistage Zeeman decelerator that has recently become operational in our laboratory [Cremers et al., Phys. Rev. A 98, 033406 (2018)] and that is specifically optimized for crossed molecular beams scattering experiments. The decelerator consists of an alternating array of 100 solenoids and 100 permanent hexapoles to guide or decelerate beams of paramagnetic atoms or molecules. The Zeeman decelerator features a modular design that is mechanically easy to extend to arbitrary length and allows for solenoid and hexapole elements that are convenient to replace. The solenoids and associated electronics are efficiently water cooled and allow the Zeeman decelerator to operate at repetition rates exceeding 10 Hz. We characterize the performance of the decelerator using various beams of metastable rare gas atoms. Imaging of the atoms that exit the Zeeman decelerator reveals the transverse focusing properties of the hexapole array in the Zeeman decelerator.

arXiv:1901.02643•Review of Scientific Instruments•Jan 1, 2019•23 citations
We demonstrate and characterize Zeeman-Sisyphus (ZS) deceleration of a beam of ytterbium monohydroxide. Our method uses a combination of large magnetic fields (\ensuremath∼2.5\ensuremath{\sim}2.5\ensuremath∼2.5 T) and optical spin-flip transitions to decelerate molecules while scattering only \ensuremath∼10\ensuremath{\sim}10\ensuremath∼10 photons per molecule. We study the challenges associated with the presence of internal molecular perturbations among the excited electronic states and discuss the methods used to overcome these challenges, including a modified ZS decelerator using microwave and optical transitions.
We present a robust, continuous molecular decelerator that employs high magnetic fields and few optical pumping steps. CaOH molecules are slowed, accumulating at low velocities in a range sufficient for loading both magnetic and magneto-optical traps. During the slowing, the molecules scatter only seven photons, removing around 8 K of energy. Because large energies can be removed with only a few spontaneous radiative decays, this method can in principle be applied to nearly any paramagnetic atomic or molecular species, opening a general path to trapping of complex molecules.
Ultracold polyatomic molecules containing heavy nuclei, such as SrOH and YbOH, are sensitive to T- symmetry violating and P-symmetry violating physics beyond the Standard Model through the electron’s electric dipole moment. Furthermore, SrOH is sensitive to ultralight Dark Matter through measuring time variations of fundamental constants. However, in order to make full use of these molecules, they need to be cooled to ultracold temperatures and held in optical traps. We have realized a magneto-optical trap (MOT) of SrOH and used this as the essential element to achieve optical trap- ping in the microKelvin temperature regime. We observed MOT lifetimes approaching 200 ms with temperatures ∼ 1 mK and observed damped oscillations in the MOT. We further cooled the SrOH molecules to ∼ 40 μ K using Λ-enhanced gray molasses, and compressed the cloud to about 100 μm size using the conveyor belt MOT technique. Using this ultracold dense cloud of SrOH, we loaded an optical dipole trap (ODT), with a molecular lifetime of 1.2(1) seconds. In separate experiments with YbOH, which is heavier than SrOH, we demonstrated a novel deceleration method (Zeeman- Sisyphus deceleration) that can slow YbOH to under 20 m/s with only a few photons scattered utilizing high magnetic fields up to 2.5 T. By driving spin-flip transitions at the maxima and minima of the magnetic fields, slowing was achieved, which is a critical first step toward loading of a MOT for this species. We addressed the challenges associated with driving spin-flip transitions in molecules that have molecular perturbations among the electronic excited states and developed an understanding of the physics of such systems that is applicable to a wide range of molecules.
We explore a technique for decelerating molecules using a static magnetic field and optical pumping. Molecules travel through a spatially varying magnetic field and are repeatedly pumped into a weak-field seeking state as they move towards each strong field region, and into a strong-field seeking state as they move towards weak field. The method is time-independent and so is suitable for decelerating both pulsed and continuous molecular beams. By using guiding magnets at each weak field region, the beam can be simultaneously guided and decelerated. By tapering the magnetic field strength in the strong field regions, and exploiting the Doppler shift, the velocity distribution can be compressed during deceleration. We develop the principles of this deceleration technique, provide a realistic design, use numerical simulations to evaluate its performance for a beam of CaF, and compare this performance to other deceleration methods.
Abstract Taming more species of molecules with large density is a long-standing goal in molecular science. Heavy molecule (> 100 amu) is of particular interest for precision measurements. However, decelerating a fast-moving beam of heavy molecules to rest remains challenging for Zeeman deceleration. Additionally, the traditional approach of pulsed Zeeman decelerator suffers from serious molecular loss during deceleration, significantly limiting its potential applications. Herein, we present a ring-shaped traveling wave Zeeman decelerator (RTWZD) featured with true three-dimensional smoothly-moving magnetic potential wells that directly solve the above intractable problems. With this approach, not only the density of the molecule can be greatly increased but also the range of molecular species for Zeeman deceleration can be extended from light to heavy. The performance of the RTWZD is characterized with both the theoretical analysis and the numerical calculation, where a group of atoms and molecules such as 7Li, 32O2, 88Sr19F and 174Yb19F are employed as testers. Losses in the traditional Zeeman decelerator can be avoided, yielding more than two orders of magnitude improvement in molecular density. These characteristics of the RTWZD make it an ideal toolbox to produce cold and dense atomic/molecular samples, enabling promising prospects for cold collision, sympathetic cooling, and precision measurement.
Extending AMO techniques of motional control to heavy polyatomic molecules opens new possibilities for precision measurements of fundamental physics. Though various laser-cooling and deceleration techniques have been applied to diatomic molecules throughout the last decade, their application to more complex molecules has heretofore been focused on light species, leaving generalizability to heavy species an open question. To investigate the high-mass frontier, we here study how to extend motional control to heavy-atom-containing polyatomic molecules. First, we discuss Zeeman-Sisyphus deceleration of YbOH, which can be used to decelerate species capable of scattering only ~10s of photons. Then, we discuss radiative slowing and magneto-optical trapping of SrOH, techniques only extendable to species capable of scattering ∼104\sim10^4∼104 photons. The last work focuses on spectroscopy of nonlinear molecules to assess the viability of extending techniques of motional control to more complex species. We find a dependence of both rotational and vibrational control on symmetry group, and identify a next-generation candidate for laser cooling. We end with a overview tying these projects together, and assessing the future of motional control along mass and complexity axes, including brief suggestions of how complementary methods to those studied here can further expand into the frontiers of molecular control.
Zeeman deceleration is a relatively new technique used to obtain full control over the velocity of paramagnetic atoms or molecules in a molecular beam. We present a detailed description of a multistage Zeeman decelerator that has recently become operational in our laboratory [Cremers et al., Phys. Rev. A 98, 033406 (2018)] and that is specifically optimized for crossed molecular beams scattering experiments. The decelerator consists of an alternating array of 100 solenoids and 100 permanent hexapoles to guide or decelerate beams of paramagnetic atoms or molecules. The Zeeman decelerator features a modular design that is mechanically easy to extend to arbitrary length and allows for solenoid and hexapole elements that are convenient to replace. The solenoids and associated electronics are efficiently water cooled and allow the Zeeman decelerator to operate at repetition rates exceeding 10 Hz. We characterize the performance of the decelerator using various beams of metastable rare gas atoms. Imaging of the atoms that exit the Zeeman decelerator reveals the transverse focusing properties of the hexapole array in the Zeeman decelerator.