Measuring the Sr $^+$ 5s $_{1/2}$ Landé $g$ -factor Using Singlet-Triplet Oscillations in a Circular Rydberg State of StrontiumMeasuring the Sr$^+$ 5s$_{1/2}$ Landé $g$-factor Using Singlet-Triplet Oscillations in a Circular Rydberg State of Strontium

Baptiste Muraz, Mathis Pepin, Corentin Guimard +3 more

Circular states of strontium are promising platforms for quantum technologies. They exhibit much longer lifetimes than laser-accessible Rydberg states and possess an optically active ionic core that can be manipulated with laser light. Here we trap circular states in optical tweezers by exploiting the dynamical polarizability of the ionic core. We measure the decay of the orbital component of a n=51 circular state and observe singlet-triplet spin oscillations arising from the interplay of vector light shifts induced by the optical tweezers, spin-orbit coupling associated with the Rydberg electron, and the difference in Landé $g$ -factor between the ionic core and the Rydberg electrons. By observing the two electron spin dynamics, we measure the spin-orbit interaction and the correction $δg \sim$ 10^(-5) of the Landé $g$ -factor of the Sr $^+$ 5s $_{1/2}$ ionic core electron with respect to that of a free electron. This provides a first high-precision measurement of $g_{\textrm{Sr}^+, 5s_{1/2}}$ = 2.002290(1).Circular states of strontium are promising platforms for quantum technologies. They exhibit much longer lifetimes than laser-accessible Rydberg states and possess an optically active ionic core that can be manipulated with laser light. Here we trap circular states in optical tweezers by exploiting the dynamical polarizability of the ionic core. We measure the decay of the orbital component of a n=51 circular state and observe singlet-triplet spin oscillations arising from the interplay of vector light shifts induced by the optical tweezers, spin-orbit coupling associated with the Rydberg electron, and the difference in Landé $g$-factor between the ionic core and the Rydberg electrons. By observing the two electron spin dynamics, we measure the spin-orbit interaction and the correction $δg \sim$ 10^(-5) of the Landé $g$-factor of the Sr$^+$ 5s$_{1/2}$ ionic core electron with respect to that of a free electron. This provides a first high-precision measurement of $g_{\textrm{Sr}^+, 5s_{1/2}}$ = 2.002290(1).

arXiv:2608.26784Aug 27, 20260 citations

Transitions between Rydberg states in two-color corotating circularly polarized laser pulses

Yonas Gebre, Joel Venzke, Agnieszka Jaroń-Becker +1 more

We present a study of higher-order Raman ($\mathrm{\ensuremath{\Lambda}}, V$, and $S$ ) transitions between Rydberg states involving the absorption and emission of at least three photons in the interaction of two-color corotating circularly polarized laser pulses with the hydrogen atom. Our analysis is based on results of numerical solutions of the corresponding time-dependent Schr\"odinger equation. The results for the interaction with ($\ensuremath{\omega},2\ensuremath{\omega}$) fields show that the simultaneous interaction with both fields results in an excited state distribution over a broad range of magnetic quantum numbers. Indications of the impact of the $\mathrm{\ensuremath{\Lambda}}, V$, and $S$ transitions are found via the analysis of final distributions resulting from the preparation of the atom in specific Rydberg states. Furthermore, we show that similar mechanisms for the redistribution of population between Rydberg states are present in two-color fields with larger differences in the central frequencies, i.e., ($\ensuremath{\omega},3\ensuremath{\omega}$) and ($\ensuremath{\omega},4\ensuremath{\omega}$) fields.We present a study of higher-order Raman ($\mathrm{\ensuremath{\Lambda}}, V$, and $S$) transitions between Rydberg states involving the absorption and emission of at least three photons in the interaction of two-color corotating circularly polarized laser pulses with the hydrogen atom. Our analysis is based on results of numerical solutions of the corresponding time-dependent Schr\"odinger equation. The results for the interaction with ($\ensuremath{\omega},2\ensuremath{\omega}$) fields show that the simultaneous interaction with both fields results in an excited state distribution over a broad range of magnetic quantum numbers. Indications of the impact of the $\mathrm{\ensuremath{\Lambda}}, V$, and $S$ transitions are found via the analysis of final distributions resulting from the preparation of the atom in specific Rydberg states. Furthermore, we show that similar mechanisms for the redistribution of population between Rydberg states are present in two-color fields with larger differences in the central frequencies, i.e., ($\ensuremath{\omega},3\ensuremath{\omega}$) and ($\ensuremath{\omega},4\ensuremath{\omega}$) fields.

Physical Review AJan 5, 20210 citations

Spin-exchange interactions between circular Rydberg atoms over long times

Andrés Durán-Hernández, Gautier Creutzer, Aurore Alice Young +5 more

Arrays of neutral atoms excited to Rydberg levels have emerged as one of the most promising platforms for quantum computation and simulation. With the hope to outperform classical devices, the number of atoms has been increased by orders of magnitude. However, the interaction time, i.e., the maximum accumulated time during which an atom interacts with its neighbours, has been limited to a few microseconds only. This restrains the number of gates per atom or prevents the simulation of long-time dynamics of quantum many-body systems. Here, we observe the spin-exchange interaction between two spin 1/2s encoded in laser-trapped circular Rydberg atoms over more than $60μs$ and 40 spin-oscillation periods, improving the state of the art by an order of magnitude. These unprecedented timescales allow us to record for weak atomic trapping a collapse and revival of the spin-exchange oscillation contrast induced by spin-motion coupling. Our results constitute the first observation of this coupling with laser-trapped Rydberg atoms. To counteract its detrimental effect for quantum simulation, we demonstrate a novel dynamical decoupling method that prevents the collapse of the spin oscillations. This method exploits the advantages of our recently developed hybrid platform that enables the measurement and the optical manipulation of long-lived circular Rydberg atoms with auxiliary Rydberg atoms. This work opens a direct route to long-duration quantum simulation of strongly-interacting many-body systems.Arrays of neutral atoms excited to Rydberg levels have emerged as one of the most promising platforms for quantum computation and simulation. With the hope to outperform classical devices, the number of atoms has been increased by orders of magnitude. However, the interaction time, i.e., the maximum accumulated time during which an atom interacts with its neighbours, has been limited to a few microseconds only. This restrains the number of gates per atom or prevents the simulation of long-time dynamics of quantum many-body systems. Here, we observe the spin-exchange interaction between two spin 1/2s encoded in laser-trapped circular Rydberg atoms over more than $60μs$ and 40 spin-oscillation periods, improving the state of the art by an order of magnitude. These unprecedented timescales allow us to record for weak atomic trapping a collapse and revival of the spin-exchange oscillation contrast induced by spin-motion coupling. Our results constitute the first observation of this coupling with laser-trapped Rydberg atoms. To counteract its detrimental effect for quantum simulation, we demonstrate a novel dynamical decoupling method that prevents the collapse of the spin oscillations. This method exploits the advantages of our recently developed hybrid platform that enables the measurement and the optical manipulation of long-lived circular Rydberg atoms with auxiliary Rydberg atoms. This work opens a direct route to long-duration quantum simulation of strongly-interacting many-body systems.

physics.atom-phCross-listedarXiv:2609.37766Sep 30, 20260 citations

Theory of Laser Oscillation

Kōichi Shimoda

Springer series in optical sciences/SPringer series in optical sciencesJan 1, 19860 citations

Theory of Laser Oscillation

Kōichi Shimoda

Springer series in optical sciences/SPringer series in optical sciencesJan 1, 19840 citations

Measuring the Sr

^+

_{1/2}

Landé

g

-factor Using Singlet-Triplet Oscillations in a Circular Rydberg State of Strontium

g

-factor between the ionic core and the Rydberg electrons. By observing the two electron spin dynamics, we measure the spin-orbit interaction and the correction

δg \sim

10^(-5) of the Landé

g

-factor of the Sr

^+

_{1/2}

ionic core electron with respect to that of a free electron. This provides a first high-precision measurement of

g_{\textrm{Sr}^+, 5s_{1/2}}

= 2.002290(1).

We present a study of higher-order Raman ($\mathrm{\ensuremath{\Lambda}}, V$, and

S

) transitions between Rydberg states involving the absorption and emission of at least three photons in the interaction of two-color corotating circularly polarized laser pulses with the hydrogen atom. Our analysis is based on results of numerical solutions of the corresponding time-dependent Schr\"odinger equation. The results for the interaction with ($\ensuremath{\omega},2\ensuremath{\omega}$) fields show that the simultaneous interaction with both fields results in an excited state distribution over a broad range of magnetic quantum numbers. Indications of the impact of the $\mathrm{\ensuremath{\Lambda}}, V$, and

S

transitions are found via the analysis of final distributions resulting from the preparation of the atom in specific Rydberg states. Furthermore, we show that similar mechanisms for the redistribution of population between Rydberg states are present in two-color fields with larger differences in the central frequencies, i.e., ($\ensuremath{\omega},3\ensuremath{\omega}$) and ($\ensuremath{\omega},4\ensuremath{\omega}$) fields.

60μs

and 40 spin-oscillation periods, improving the state of the art by an order of magnitude. These unprecedented timescales allow us to record for weak atomic trapping a collapse and revival of the spin-exchange oscillation contrast induced by spin-motion coupling. Our results constitute the first observation of this coupling with laser-trapped Rydberg atoms. To counteract its detrimental effect for quantum simulation, we demonstrate a novel dynamical decoupling method that prevents the collapse of the spin oscillations. This method exploits the advantages of our recently developed hybrid platform that enables the measurement and the optical manipulation of long-lived circular Rydberg atoms with auxiliary Rydberg atoms. This work opens a direct route to long-duration quantum simulation of strongly-interacting many-body systems.