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:2505.10115 · Physical Review Research

Collective light shifts of many longitudinal cavity modes induced by coupling to a cold-atom ensemble

Marin Ðujić, Mateo Kruljac, Lovre Kardum, Neven Šantić, Damir Aumiler, Ivor Krešić, Ticijana Ban

Published Feb 20, 2026• 1 citation
arXivHTMLPDF

Abstract

We experimentally study the interaction between a cold-atom cloud and many longitudinal modes of a high-quality Fabry-Perot cavity, by measuring signatures of collective light shifts in the cavity transmission spectrum of an optical frequency comb probe. Using a resonator coupled to more than 10 5 intracavity atoms, we detect significant shifts of ∼ 100 cavity modes simultaneously, which is a direct manifestation of physics beyond the hitherto explored regime of cavity-cold atom interaction with only single or few longitudinal modes at a time. For the cavity mode closest to the atomic resonance, we demonstrate a bistability in the transmission spectrum, arising due to a combined coupling of the cloud to an external pump laser and a cavity mode probed by the optical frequency comb. These results provide a first step toward deeper exploration of multifrequency cavity quantum electrodynamics, where ultrashort pulsed sources could be used for optical manipulation, cooling, and entanglement of cold atoms in a resonator.

DOI
10.1103/fy4n-mj4d

Related papers

Cavity Optomechanics with synthetic Landau levels of ultra cold Fermi gas

Sankalpa Ghosh, Bikash Padhi

Ultracold fermionic atoms placed in a synthetic magnetic field arrange themselves in Landau levels. We theoretically study the optomechanical interaction between the light field and collective excitations of such fermionic atoms in synthetic magnetic field by placing them inside a Fabry-Perot cavity. We derive the effective Hamiltonian for particle hole excitations from a filled Landau level using a bosonization technique and obtain an expression for the cavity transmission spectrum. Using this we show that the cavity transmission spectrum demonstrates cold atom analog of Shubnikov‐de Haas oscillation in electronic condensed matter systems. We discuss the experimental consequences for this oscillation for such a system and the related optical bistability. By allowing an ultracold atomic ensemble to interact with a selected mode of a high-finesse cavity it is possible to probe the quantum many-body state of such an ultracold atomic system. The resulting cavity optomechanics or cavity quantum electrodynamics with ultracold atoms has recently witnessed a significant development [1]. The experimental successes include the coupling of collective density excitation of an ultracold bosonic condensate with a single-cavity mode and observation of the coupled dynamics through cavity transmission [2], a strongly coupled cavity mode with a highly localized ultracold atomic condensate trapped inside a single antinode of a cavity field [3], demonstration of strong ultracold atomcavity-coupling-induced optical nonlinearity even at low photon density [4], and selected atom-photon coupling of a single atomic ensemble in a multiensemble system [5 ]t o name a few. In another development, there has been significant experimental and theoretical progress in studying the effect of optically induced artificial or synthetic gauge field [6] on such neutral atoms, making it a playground for quantum simulation of phenomena that occur when an electronic condensed matter system is placed in a real magnetic field. The experimental achievements in this direction include the observation of vortices, Abrikosov vortex lattice in trapped ultracold atomic superfluid initially by achieving the synthetic magnetic field through the rotation of the trap [7], and later by Raman laser induced spatially varying coupling of the hyperfine states of such ultracold atoms [8]. A more recent development in this direction includes the creation of optical flux lattices [9], realization of spin-orbit coupling for such neutral ultracold bosonic [10] and fermionic atoms [11] with the possibility of creating ultracold atomic analogs of topological condensed matter phases [12]. This Letter aims to combine these two developments by considering a system of such ultracold atoms trapped inside a high-finesse Fabry-Perot cavity interacting with

Bulletin of the American Physical Society•Mar 4, 2014•1 citation

Atomic coherence and interference in a coupled atom–cavity system

Jiepeng Zhang, Gessler Hernandez, Yifu Zhu

When a coherently prepared atomic medium is confined in an optical cavity, the atomic coherence and interference manifested by electromagnetically induced transparency (EIT) can be manipulated and enhanced by the collective atom–cavity coupling and the cavity feedback. We present an experimental study of the light transmission through an optical cavity coupled with coherently prepared cold Rb atoms. In the frequency domain, the cavity transmission spectrum exhibits spectral peaks representing the cavity normal modes associated with the multi-atom vacuum Rabi splitting and the intra-cavity dark state manifested by the combined EIT effects of the absorption suppression and the steep normal dispersion. In the time domain, a light pulse coupled into the cavity mode propagates with a slow group velocity and the propagation time delay is significantly increased by the cavity feedback.

Journal of Modern Optics•Aug 14, 2009•3 citations

Cavity quantum optomechanics with ultracold atoms

Kater W. Murch

A common goal of recent research is the elucidation and control over quantum mechanical behavior in ever-larger physical systems. In this thesis I present an alternative target for investigating the quantum motion of macroscopic bodies: the collective motion of an ultracold atomic gas trapped within a high-finesse Fabry-Perot optical cavity in the single-atom strong-coupling regime of cavity quantum electrodynamics (CQED). When ultracold atoms are trapped in the Lamb-Dicke regime, the cavity-mode structure selects a single collective degree of freedom that is at once actuated by the optical forces from cavity probe light and measured by the cavity’s optical properties. Dispersive optical bistability arising from collective motion of the atomic medium was observed. Measurement of the collective motion was subject to quantum measurement backaction by the quantum force fluctuations of the cavity optical field. The strength and spectrum of these backaction force fluctuations was measured by quantifying the cavity-light-induced heating rate of the intracavity atomic ensemble, finding quantitative agreement with the expected heating rate from quantum optical fluctuations. Dynamical phenomena in the optomechanical system were explored experimentally and theoretically. Quantum limited measurements are discussed and were

•Jan 1, 2008•5 citations

Observation of collective bistability in an ultracold cloud of strongly driven strontium atoms interacting with a ring cavity

Yajaira Dalila Rivero Jerez

We report on our progress in the construction of a machine capable of cooling Strontium atoms to ultra-cold temperatures, to interact collectively with the modes of a ring cavity.We present the first observation of a novel manifestation of saturation-induced optical bistability in a resonantly pumped optical ring cavity, interacting with a narrow atomic transition cloud.The bistability emerges, above a critical pump rate, as an additional peak in the cavity's normal-mode spectra near the atomic resonance.The new regime addressed for our machine takes advantage of the narrow atomic transition enabling the observation of bistability in a strong resonant regime where the atoms couple collectively to the cavity.

•Dec 14, 2022•1 citation

Intracavity cold atomic ensemble with high optical depth

Yue Jiang, Yefeng Mei, Yueyang Zou +2 more

We describe the apparatus of an optical cavity loaded with cold 85Rb atoms of high optical depth (OD) in the weak coupling regime. The relevant cavity-atom parameters are the single-photon Rabi frequency g0 = 2π × 0.25 MHz, the cavity power decay rate κ = 2π × 9.0 MHz, and the atomic excited state decay rate Γ = 2π × 5.75 MHz. In this bad-cavity configuration where the atomic natural linewidth (Γ/2π) is less than the cavity linewidth (κ/2π), the cavity enhancement factor for the longitudinal OD is about 188. We obtain a cavity enhanced OD up to 7600, corresponding to an atomic ensemble with a bare single-pass OD of 40, coupled to the cavity mode. Our intracavity cold atomic ensemble with high OD may have many applications in studying collective atom-light interaction inside an optical cavity.

Review of Scientific Instruments•Jan 1, 2019•11 citations

Observation of Collective Superstrong Coupling of Cold Atoms to a 30-m Long Optical Resonator

Aisling Johnson, Martin Blaha, Alexander E. Ulanov +3 more

We report on the observation of collective superstrong coupling of a small ensemble of atoms interacting with the field of a 30-m long fiber resonator containing a nanofiber section. The collective light-matter coupling strength exceeds the free-spectral range and the atoms couple to consecutive longitudinal resonator modes. The measured transmission spectra of the coupled atom-resonator system provide evidence of this regime, realized with a few hundred atoms with an intrinsic single-atom cooperativity of 0.13. These results are the starting point for studies in a new setting of light-matter interaction, with strong quantum nonlinearities and a new type of dynamics.

arXiv:1905.07353•Physical Review Letters•Dec 11, 2019•39 citations
We experimentally study the interaction between a cold-atom cloud and many longitudinal modes of a high-quality Fabry-Perot cavity, by measuring signatures of collective light shifts in the cavity transmission spectrum of an optical frequency comb probe. Using a resonator coupled to more than 10 5 intracavity atoms, we detect significant shifts of ∼ 100 cavity modes simultaneously, which is a direct manifestation of physics beyond the hitherto explored regime of cavity-cold atom interaction with only single or few longitudinal modes at a time. For the cavity mode closest to the atomic resonance, we demonstrate a bistability in the transmission spectrum, arising due to a combined coupling of the cloud to an external pump laser and a cavity mode probed by the optical frequency comb. These results provide a first step toward deeper exploration of multifrequency cavity quantum electrodynamics, where ultrashort pulsed sources could be used for optical manipulation, cooling, and entanglement of cold atoms in a resonator.
Ultracold fermionic atoms placed in a synthetic magnetic field arrange themselves in Landau levels. We theoretically study the optomechanical interaction between the light field and collective excitations of such fermionic atoms in synthetic magnetic field by placing them inside a Fabry-Perot cavity. We derive the effective Hamiltonian for particle hole excitations from a filled Landau level using a bosonization technique and obtain an expression for the cavity transmission spectrum. Using this we show that the cavity transmission spectrum demonstrates cold atom analog of Shubnikov‐de Haas oscillation in electronic condensed matter systems. We discuss the experimental consequences for this oscillation for such a system and the related optical bistability. By allowing an ultracold atomic ensemble to interact with a selected mode of a high-finesse cavity it is possible to probe the quantum many-body state of such an ultracold atomic system. The resulting cavity optomechanics or cavity quantum electrodynamics with ultracold atoms has recently witnessed a significant development [1]. The experimental successes include the coupling of collective density excitation of an ultracold bosonic condensate with a single-cavity mode and observation of the coupled dynamics through cavity transmission [2], a strongly coupled cavity mode with a highly localized ultracold atomic condensate trapped inside a single antinode of a cavity field [3], demonstration of strong ultracold atomcavity-coupling-induced optical nonlinearity even at low photon density [4], and selected atom-photon coupling of a single atomic ensemble in a multiensemble system [5 ]t o name a few. In another development, there has been significant experimental and theoretical progress in studying the effect of optically induced artificial or synthetic gauge field [6] on such neutral atoms, making it a playground for quantum simulation of phenomena that occur when an electronic condensed matter system is placed in a real magnetic field. The experimental achievements in this direction include the observation of vortices, Abrikosov vortex lattice in trapped ultracold atomic superfluid initially by achieving the synthetic magnetic field through the rotation of the trap [7], and later by Raman laser induced spatially varying coupling of the hyperfine states of such ultracold atoms [8]. A more recent development in this direction includes the creation of optical flux lattices [9], realization of spin-orbit coupling for such neutral ultracold bosonic [10] and fermionic atoms [11] with the possibility of creating ultracold atomic analogs of topological condensed matter phases [12]. This Letter aims to combine these two developments by considering a system of such ultracold atoms trapped inside a high-finesse Fabry-Perot cavity interacting with
When a coherently prepared atomic medium is confined in an optical cavity, the atomic coherence and interference manifested by electromagnetically induced transparency (EIT) can be manipulated and enhanced by the collective atom–cavity coupling and the cavity feedback. We present an experimental study of the light transmission through an optical cavity coupled with coherently prepared cold Rb atoms. In the frequency domain, the cavity transmission spectrum exhibits spectral peaks representing the cavity normal modes associated with the multi-atom vacuum Rabi splitting and the intra-cavity dark state manifested by the combined EIT effects of the absorption suppression and the steep normal dispersion. In the time domain, a light pulse coupled into the cavity mode propagates with a slow group velocity and the propagation time delay is significantly increased by the cavity feedback.
A common goal of recent research is the elucidation and control over quantum mechanical behavior in ever-larger physical systems. In this thesis I present an alternative target for investigating the quantum motion of macroscopic bodies: the collective motion of an ultracold atomic gas trapped within a high-finesse Fabry-Perot optical cavity in the single-atom strong-coupling regime of cavity quantum electrodynamics (CQED). When ultracold atoms are trapped in the Lamb-Dicke regime, the cavity-mode structure selects a single collective degree of freedom that is at once actuated by the optical forces from cavity probe light and measured by the cavity’s optical properties. Dispersive optical bistability arising from collective motion of the atomic medium was observed. Measurement of the collective motion was subject to quantum measurement backaction by the quantum force fluctuations of the cavity optical field. The strength and spectrum of these backaction force fluctuations was measured by quantifying the cavity-light-induced heating rate of the intracavity atomic ensemble, finding quantitative agreement with the expected heating rate from quantum optical fluctuations. Dynamical phenomena in the optomechanical system were explored experimentally and theoretically. Quantum limited measurements are discussed and were
We report on our progress in the construction of a machine capable of cooling Strontium atoms to ultra-cold temperatures, to interact collectively with the modes of a ring cavity.We present the first observation of a novel manifestation of saturation-induced optical bistability in a resonantly pumped optical ring cavity, interacting with a narrow atomic transition cloud.The bistability emerges, above a critical pump rate, as an additional peak in the cavity's normal-mode spectra near the atomic resonance.The new regime addressed for our machine takes advantage of the narrow atomic transition enabling the observation of bistability in a strong resonant regime where the atoms couple collectively to the cavity.
We describe the apparatus of an optical cavity loaded with cold 85Rb atoms of high optical depth (OD) in the weak coupling regime. The relevant cavity-atom parameters are the single-photon Rabi frequency g0 = 2π × 0.25 MHz, the cavity power decay rate κ = 2π × 9.0 MHz, and the atomic excited state decay rate Γ = 2π × 5.75 MHz. In this bad-cavity configuration where the atomic natural linewidth (Γ/2π) is less than the cavity linewidth (κ/2π), the cavity enhancement factor for the longitudinal OD is about 188. We obtain a cavity enhanced OD up to 7600, corresponding to an atomic ensemble with a bare single-pass OD of 40, coupled to the cavity mode. Our intracavity cold atomic ensemble with high OD may have many applications in studying collective atom-light interaction inside an optical cavity.
We report on the observation of collective superstrong coupling of a small ensemble of atoms interacting with the field of a 30-m long fiber resonator containing a nanofiber section. The collective light-matter coupling strength exceeds the free-spectral range and the atoms couple to consecutive longitudinal resonator modes. The measured transmission spectra of the coupled atom-resonator system provide evidence of this regime, realized with a few hundred atoms with an intrinsic single-atom cooperativity of 0.13. These results are the starting point for studies in a new setting of light-matter interaction, with strong quantum nonlinearities and a new type of dynamics.