Abstract
Interactions between atoms and light in optical cavities provide a means of investigating collective (many-body) quantum physics in controlled environments. Such ensembles of atoms in cavities have been proposed for studying collective quantum spin models, where the atomic internal levels mimic a spin degree of freedom and interact through long-range interactions tunable by changing the cavity parameters1,2,3,4. Non-classical steady-state phases arising from the interplay between atom–light interactions and dissipation of light from the cavity have previously been investigated5,6,7,8,9,10,11. These systems also offer the opportunity to study dynamical phases of matter that are precluded from existence at equilibrium but can be stabilized by driving a system out of equilibrium12,13,14,15,16, as demonstrated by recent experiments17,18,19,20,21,22. These phases can also display universal behaviours akin to standard equilibrium phase transitions8,23,24. Here, we use an ensemble of about a million strontium-88 atoms in an optical cavity to simulate a collective Lipkin–Meshkov–Glick model25,26, an iconic model in quantum magnetism, and report the observation of distinct dynamical phases of matter in this system. Our system allows us to probe the dependence of dynamical phase transitions on system size, initial state and other parameters. These observations can be linked to similar dynamical phases in related systems, including the Josephson effect in superfluid helium27, or coupled atomic28 and solid-state polariton29 condensates. The system itself offers potential for generation of metrologically useful entangled states in optical transitions, which could permit quantum enhancement in state-of-the-art atomic clocks30,31.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout




Similar content being viewed by others
Data availability
Data relevant to the figures and conclusions of this manuscript are available at https://doi.org/10.5061/dryad.mgqnk98w951.
Code availability
The codes used in the analysis of experimental data and to carry out associated theoretical calculations are available from the corresponding authors upon reasonable request.
References
Leroux, I. D., Schleier-Smith, M. H. & Vuletić, V. Implementation of cavity squeezing of a collective atomic spin. Phys. Rev. Lett. 104, 073602 (2010).
Norcia, M. A. et al. Cavity-mediated collective spin-exchange interactions in a strontium superradiant laser. Science 361, 259–262 (2018).
Davis, E. J., Bentsen, G., Homeier, L., Li, T. & Schleier-Smith, M. H. Photon-mediated spin-exchange dynamics of spin-1 atoms. Phys. Rev. Lett. 122, 010405 (2019).
Vaidya, V. D. et al. Tunable-range, photon-mediated atomic interactions in multimode cavity QED. Phys. Rev. X 8, 011002 (2018).
Baumann, K., Guerlin, C., Brennecke, F. & Esslinger, T. Dicke quantum phase transition with a superfluid gas in an optical cavity. Nature 464, 1301–1306 (2010).
Klinder, J., Keßler, H., Wolke, M., Mathey, L. & Hemmerich, A. Dynamical phase transition in the open Dicke model. Proc. Natl Acad. Sci. USA 112, 3290–3295 (2015).
Baden, M. P., Arnold, K. J., Grimsmo, A. L., Parkins, S. & Barrett, M. D. Realization of the Dicke model using cavity-assisted Raman transitions. Phys. Rev. Lett. 113, 020408 (2014).
Ritsch, H., Domokos, P., Brennecke, F. & Esslinger, T. Cold atoms in cavity-generated dynamical optical potentials. Rev. Mod. Phys. 85, 553–601 (2013).
Landini, M. et al. Formation of a spin texture in a quantum gas coupled to a cavity. Phys. Rev. Lett. 120, 223602 (2018).
Kroeze, R. M., Guo, Y., Vaidya, V. D., Keeling, J. & Lev, B. L. Spinor self-ordering of a quantum gas in a cavity. Phys. Rev. Lett. 121, 163601 (2018).
Kroeze, R. M., Guo, Y. & Lev, B. L. Dynamical spin–orbit coupling of a quantum gas. Phys. Rev. Lett. 123, 160404 (2019).
Heyl, M., Polkovnikov, A. & Kehrein, S. Dynamical quantum phase transitions in the transverse-field Ising model. Phys. Rev. Lett. 110, 135704 (2013).
Žunkovič, B., Heyl, M., Knap, M. & Silva, A. Dynamical quantum phase transitions in spin chains with long-range interactions: merging different concepts of nonequilibrium criticality. Phys. Rev. Lett. 120, 130601 (2018).
Eckstein, M., Kollar, M. & Werner, P. Thermalization after an interaction quench in the Hubbard model. Phys. Rev. Lett. 103, 056403 (2009).
Lamacraft, A. & Moore, J. in Ultracold Bosonic and Fermionic Gases (eds Levin, K. et al.) 177–202 (Elsevier, 2012).
Nandkishore, R. & Huse, D. A. Many-body localization and thermalization in quantum statistical mechanics. Annu. Rev. Condens. Matter Phys. 6, 15–38 (2015).
Zhang, J. et al. Observation of a many-body dynamical phase transition with a 53-qubit quantum simulator. Nature 551, 601–604 (2017).
Fläschner, N. et al. Observation of dynamical vortices after quenches in a system with topology. Nat. Phys. 14, 265 (2018).
Jurcevic, P. et al. Direct observation of dynamical quantum phase transitions in an interacting many-body system. Phys. Rev. Lett. 119, 080501 (2017).
Smale, S. et al. Observation of a transition between dynamical phases in a quantum degenerate Fermi gas. Sci. Adv. 5, eaax1568 (2019).
Zhang, J. et al. Observation of a discrete time crystal. Nature 543, 217–220 (2017).
Choi, S. et al. Observation of discrete time-crystalline order in a disordered dipolar many-body system. Nature 543, 221–225 (2017).
Prüfer, M. et al. Observation of universal dynamics in a spinor Bose gas far from equilibrium. Nature 563, 217–220 (2018).
Erne, S., Bücker, R., Gasenzer, T., Berges, J. & Schmiedmayer, J. Universal dynamics in an isolated one-dimensional Bose gas far from equilibrium. Nature 563, 225–229 (2018).
Lipkin, H., Meshkov, N. & Glick, A. Validity of many-body approximation methods for a solvable model: (I). Exact solutions and perturbation theory. Nucl. Phys. 62, 188–198 (1965).
Ribeiro, P., Vidal, J. & Mosseri, R. Thermodynamical limit of the Lipkin–Meshkov–Glick model. Phys. Rev. Lett. 99, 050402 (2007).
Backhaus, S. et al. Discovery of a metastable-state in a superfluid 3He weak link. Nature 392, 687–690 (1998).
Albiez, M. et al. Direct observation of tunneling and nonlinear self-trapping in a single bosonic Josephson junction. Phys. Rev. Lett. 95, 010402 (2005).
Abbarchi, M. et al. Macroscopic quantum self-trapping and Josephson oscillations of exciton polaritons. Nat. Phys. 9, 275–279 (2013).
Campbell, S. L. et al. A Fermi-degenerate three-dimensional optical lattice clock. Science 358, 90–94 (2017).
Ludlow, A. D., Boyd, M. M., Ye, J., Peik, E. & Schmidt, P. O. Optical atomic clocks. Rev. Mod. Phys. 87, 637–701 (2015).
Cazalilla, M. A. & Rey, A. M. Ultracold Fermi gases with emergent SU(n) symmetry. Rep. Prog. Phys. 77, 124401 (2014).
Daley, A. J. Quantum computing and quantum simulation with group-II atoms. Quantum Inform. Process. 10, 865 (2011).
Marino, J. & Diehl, S. Quantum dynamical field theory for nonequilibrium phase transitions in driven open systems. Phys. Rev. B 94, 085150 (2016).
Barberena, D., Lewis-Swan, R. J., Thompson, J. K. & Rey, A. M. Driven-dissipative quantum dynamics in ultra-long-lived dipoles in an optical cavity. Phys. Rev. A 99, 053411 (2019).
Mivehvar, F., Piazza, F. & Ritsch, H. Disorder-driven density and spin self-ordering of a Bose–Einstein condensate in a cavity. Phys. Rev. Lett. 119, 063602 (2017).
Schiró, M. & Fabrizio, M. Time-dependent mean field theory for quench dynamics in correlated electron systems. Phys. Rev. Lett. 105, 076401 (2010).
Sciolla, B. & Biroli, G. Quantum quenches and off-equilibrium dynamical transition in the infinite-dimensional Bose–Hubbard model. Phys. Rev. Lett. 105, 220401 (2010).
Gambassi, A. & Calabrese, P. Quantum quenches as classical critical films. Europhys. Lett. 95, 66007 (2011).
Smacchia, P., Knap, M., Demler, E. & Silva, A. Exploring dynamical phase transitions and prethermalization with quantum noise of excitations. Phys. Rev. B 91, 205136 (2015).
Smerzi, A., Fantoni, S., Giovanazzi, S. & Shenoy, S. R. Quantum coherent atomic tunneling between two trapped Bose–Einstein condensates. Phys. Rev. Lett. 79, 4950–4953 (1997).
Reinhard, A. et al. Self-trapping in an array of coupled 1D Bose gases. Phys. Rev. Lett. 110, 033001 (2013).
Lerose, A., Žunkovič, B., Marino, J., Gambassi, A. & Silva, A. Impact of non-equilibrium fluctuations on pre-thermal dynamical phase transitions in long-range interacting spin chains. Phys. Rev. B 99, 045128 (2019).
Barankov, R. A., Levitov, L. S. & Spivak, B. Z. Collective Rabi oscillations and solitons in a time-dependent BCS pairing problem. Phys. Rev. Lett. 93, 160401 (2004).
Yuzbashyan, E. A., Dzero, M., Gurarie, V. & Foster, M. S. Quantum quench phase diagrams of an s-wave BCS–BEC condensate. Phys. Rev. A 91, 033628 (2015).
Swingle, B., Bentsen, G., Schleier-Smith, M. & Hayden, P. Measuring the scrambling of quantum information. Phys. Rev. A 94, 040302 (2016).
Swingle, B. Unscrambling the physics of out-of-time-order correlators. Nat. Phys. 14, 988–990 (2018).
Norcia, M. A. & Thompson, J. K. Strong coupling on a forbidden transition in strontium and nondestructive atom counting. Phys. Rev. A 93, 023804 (2016).
Norcia, M. A. et al. Frequency measurements of superradiance from the strontium clock transition. Phys. Rev. X 8, 021036 (2018).
Norcia, M. A., Winchester, M. N., Cline, J. R. K. & Thompson, J. K. Superradiance on the millihertz linewidth strontium clock transition. Sci. Adv. 2, e1601231 (2016).
Muniz Silva, J. A. et al. Exploring dynamical phase transitions with a cavity-QED platform, v2. Dryad dataset (2020); https://doi.org/10.5061/dryad.mgqnk98w9.
Acknowledgements
We acknowledge discussions with I. Spielman, M. Holland and A. Shankar. This work is supported by the Air Force Office of Scientific Research (AFOSR) grant FA9550-18-1-0319, by the Defense Advanced Research Projects Agency (DARPA) Extreme Sensing and ARO grant W911NF-16-1-0576, the ARO single investigator award W911NF-19-1-0210, the US National Science Foundation (NSF) PHY1820885, NSF JILA-PFC PHY-1734006 grants, and by the National Institute of Standards and Technology (NIST). J.R.K.C. acknowledges financial support from NSF GRFP.
Author information
Authors and Affiliations
Contributions
J.A.M., D.J.Y., J.R.K.C. and J.K.T. collected and analysed the experimental data. R.J.L.-S., D.B. and A.M.R. developed the theoretical model. All authors discussed the results and contributed to the preparation of the manuscript.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Peer review information Nature thanks Murray Barrett, Maria Luisa Chiofalo and Farokh Mivehvar for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data figures and tables
Extended Data Fig. 1 Experimental platform.
a, An optical cavity is driven by a 689-nm coherent field that establishes an intra-cavity field \({\varOmega }_{{\rm{p}}}{{\rm{e}}}^{{\rm{i}}{\omega }_{{\rm{p}}}t}\), which is near resonance with the 1S0 to 3P1 transition in 88Sr. Inside the cavity, an ensemble of atoms is confined in a 1D optical lattice at 813 nm. Different lasers are applied for shelving excited-state atoms into long-lived metastable excited states, for freezing the system dynamics, for applying a radiation pressure force that pushes ground states in a direction transverse to the cavity axis, for optically pumping atoms from long lived metastable excited states back to the ground state, and for fluorescence imaging of atoms in the ground state. b, A typical fluorescence image captured on a CCD, showing the state-resolved imaging technique. The Ne excited state atoms that were shelved into 3P0,2 while the freeze/push beam was applied remain near the trapping region. The Ng ground-state atoms are pushed away from the trapping region. Based on their spatial location, the atoms assigned to be in the excited (ground) state are shown in false colour blue (orange). c, The relevant energy levels for 88Sr, the laser wavelengths and their functions. d, Experimental timing sequence and typical timescales.
Extended Data Fig. 2 Probing many-body dynamics and mapping the phase boundary.
a, Oscillation period as function of the cavity detuning Δ for 2Ωp/(Ng) = 0.104(4), δ = 0 and atoms starting in \(|\downarrow \,\rangle \). Blue points are experimental values, solid red line represents the mean-field prediction for the same drive and atom number, and the shaded red area represents typical experimental fluctuations on 2Ωp/(Ng). The period is extracted from sinusoidal fits to data as in Fig. 2a, after removing a linear term caused by the single-particle dephasing effects. The mean-field value (red solid line) is Tosc = 2π/(Nχ) with the effective replacements due to inhomogeneous coupling as discussed in Methods. Measurements are taken in the dispersive limit where \(\varDelta \gg \sqrt{N}g\). b, Critical detuning δc as function of the drive Δ for Δ/(2π) = ±50 MHz (red and blue points, respectively). We also plot the theoretical prediction for the phase boundary (equation (11)) with rescaled parameters, and predictions of the numerical model (solid lines) including uncertainty based on the typical fluctuations in Ω/(χN). Error bars are statistical (1σ).
Supplementary information
Supplementary Information
This Supplementary Information file contains the following sections: I, Effective spin model; II, Axial motion; III, Anomalous decoherence due to residual motion and technical noise; IV, Dynamical phase diagram; and V, Mapping between spin model and macroscopic self-trapping.
Rights and permissions
About this article
Cite this article
Muniz, J.A., Barberena, D., Lewis-Swan, R.J. et al. Exploring dynamical phase transitions with cold atoms in an optical cavity. Nature 580, 602–607 (2020). https://doi.org/10.1038/s41586-020-2224-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41586-020-2224-x
This article is cited by
-
Quantum phase transition of the Jaynes-Cummings model
Science China Physics, Mechanics & Astronomy (2024)
-
Engineering random spin models with atoms in a high-finesse cavity
Nature Physics (2023)
-
A non-equilibrium superradiant phase transition in free space
Nature Physics (2023)
-
Spectral engineering of cavity-protected polaritons in an atomic ensemble
Nature Physics (2023)
-
Light emission from strongly driven many-body systems
Nature Physics (2023)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.