Supersolid Formation in a Quantum Gas Breaking Continuous Translational Symmetry
Abstract
The concept of a supersolid state combines the crystallization of a many-body system with dissipationless flow of the atoms from which it is built. This quantum phase requires the breaking of two continuous symmetries: the phase invariance of a superfluid and the continuous translational invariance to form the crystal1,2. Despite having been proposed for helium almost 50 years ago3,4, experimental verification of supersolidity remains elusive5,6. A variant with only discrete translational symmetry breaking on a preimposed lattice structure—the 'lattice supersolid'7—has been realized, based on self-organization of a Bose–Einstein condensate8,9. However, lattice supersolids do not feature the continuous ground-state degeneracy that characterizes the supersolid state as originally proposed. Here we report the realization of a supersolid with continuous translational symmetry breaking along one direction in a quantum gas. The continuous symmetry that is broken emerges from two discrete spatial symmetries by symmetrically coupling a Bose–Einstein condensate to the modes of two optical cavities. We establish the phase coherence of the supersolid and find a high ground-state degeneracy by measuring the crystal position over many realizations through the light fields that leak from the cavities. These light fields are also used to monitor the position fluctuations in real time. Our concept provides a route to creating and studying glassy many-body systems with controllably lifted ground-state degeneracies, such as supersolids in the presence of disorder.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Discovery of quantum phases in the Shastry-Sutherland compound SrCu2(BO3)2 under extreme conditions of field and pressure
Nature Communications Open Access 28 April 2022
-
Self assembling cluster crystals from DNA based dendritic nanostructures
Nature Communications Open Access 09 December 2021
-
Extended Bose-Hubbard Model with Cavity-Mediated Infinite-Range Interactions at Finite Temperatures
Scientific Reports Open Access 03 June 2020
Access options
Subscribe to Journal
Get full journal access for 1 year
185,98 €
only 3,65 € per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Buy article
Get time limited or full article access on ReadCube.
$32.00
All prices are NET prices.
References
-
Boninsegni, M. & Prokof'ev, N. V. Supersolids: what and where are they? Rev. Mod. Phys. 84, 759–776 (2012)
-
Chan, M. H. W., Hallock, R. B. & Reatto, L. Overview on solid 4He and the issue of supersolidity. J. Low Temp. Phys. 172, 317–363 (2013)
-
Andreev, A. F. & Lifshitz, I. M. Quantum theory of defects in crystals. Sov. Phys. JETP 29, 1107–1113 (1969)
-
Thouless, D. J. The flow of a dense superfluid. Ann. Phys. 52, 403–427 (1969)
-
Kim, E. & Chan, M. H. W. Probable observation of a supersolid helium phase. Nature 427, 225–227 (2004)
-
Kim, D. Y. & Chan, M. H. W. Absence of supersolidity in solid helium in porous Vycor glass. Phys. Rev. Lett. 109, 155301 (2012)
-
Matsuda, H. & Tsuneto, T. Off-diagonal long-range order in solids. Prog. Theor. Phys. 46, 411–436 (1970)
-
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)
-
Mottl, R. et al. Roton-type mode softening in a quantum gas with cavity-mediated long-range interactions. Science 336, 1570–1573 (2012)
-
Bloch, I., Dalibard, J. & Zwerger, W. Many-body physics with ultracold gases. Rev. Mod. Phys. 80, 885–964 (2008)
-
Lahaye, T., Menotti, C., Santos, L., Lewenstein, M. & Pfau, T. The physics of dipolar bosonic quantum gases. Rep. Prog. Phys. 72, 126401 (2009)
-
Kadau, H. et al. Observing the Rosensweig instability of a quantum ferrofluid. Nature 530, 194–197 (2016)
-
Zeiher, J. et al. Many-body interferometry of a Rydberg-dressed spin lattice. Nat. Phys. 12, 1095–1099 (2016)
-
Moses, S. A. et al. Creation of a low-entropy quantum gas of polar molecules in an optical lattice. Science 350, 659–662 (2015)
-
Goldman, N., Juzeliūnas, G., Öhberg, P. & Spielman, I. B. Light-induced gauge fields for ultracold atoms. Rep. Prog. Phys. 77, 126401 (2014)
-
Li, J. et al. Spin-orbit coupling and spin textures in optical superlattices. Phys. Rev. Lett. 117, 185301 (2016)
-
Ostermann, S., Piazza, F. & Ritsch, H. Spontaneous crystallization of light and ultracold atoms. Phys. Rev. X 6, 021026 (2016)
-
Gopalakrishnan, S., Lev, B. L. & Goldbart, P. M. Emergent crystallinity and frustration with Bose–Einstein condensates in multimode cavities. Nat. Phys. 5, 845–850 (2009)
-
Labeyrie, G. et al. Optomechanical self-structuring in a cold atomic gas. Nat. Photon. 8, 321–325 (2014)
-
Kollár, A. J. et al. Supermode-density-wave-polariton condensation. Preprint at https://arxiv.org/abs/1606.04127 (2016)
-
Lemoine, M., Martin, J. & Peter, P. (eds) Inflationary Cosmology Ch. 11 (Springer, 2008)
-
Eichhorn, A., Mesterházy, D. & Scherer, M. M. Multicritical behavior in models with two competing order parameters. Phys. Rev. E 88, 042141 (2013)
-
Ritsch, H., Domokos, P., Brennecke, F. & Esslinger, T. Cold atoms in cavity-generated dynamical optical potentials. Rev. Mod. Phys. 85, 553–601 (2013)
-
Asbóth, J. K., Domokos, P. & Ritsch, H. Correlated motion of two atoms trapped in a single-mode cavity field. Phys. Rev. A 70, 013414 (2004)
-
Safaei, S., Miniatura, C. & Grémaud, B. Triangular and honeycomb lattices of cold atoms in optical cavities. Phys. Rev. A 92, 043810 (2015)
-
Nagy, D., Szirmai, G. & Domokos, P. Critical exponent of a quantum-noise-driven phase transition: the open-system Dicke model. Phys. Rev. A 84, 043637 (2011)
-
Brennecke, F. et al. Real-time observation of fluctuations at the driven-dissipative Dicke phase transition. Proc. Natl Acad. Sci. USA 110, 11763–11767 (2013)
-
Strack, P. & Sachdev, S. Dicke quantum spin glass of atoms and photons. Phys. Rev. Lett. 107, 277202 (2011)
-
Fan, J. et al. Hidden continuous symmetry and Nambu-Goldstone mode in a two-mode Dicke model. Phys. Rev. A 89, 023812 (2014)
-
Baksic, A. & Ciuti, C. Controlling discrete and continuous symmetries in "superradiant" phase transitions with circuit QED systems. Phys. Rev. Lett. 112, 173601 (2014)
-
Léonard, J. et al. Optical transport of ultracold atoms using focus-tunable lenses. New J. Phys. 16, 093028 (2014)
-
Emary, C. & Brandes, T. Chaos and the quantum phase transition in the Dicke model. Phys. Rev. E 67, 066203 (2003)
-
Hayn, M., Emary, C. & Brandes, T. Phase transitions and dark-state physics in two-color superradiance. Phys. Rev. A 84, 053856 (2011)
Acknowledgements
We thank E. Demler, J. Larson and B. P. Venkatesh for discussions on U(1) symmetries in optical cavities and M. Lee for contributions in the building stage of the experimental apparatus. We acknowledge funding from Synthetic Quantum Many-Body Systems (European Research Council advanced grant) and the EU Collaborative Project TherMiQ (Grant Agreement 618074), and also SBFI support for Horizon2020 project QUIC and SNF support for NCCR QSIT and DACH project 'Quantum Crystals of Matter and Light'.
Author information
Authors and Affiliations
Contributions
All authors contributed extensively to the work presented here.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Additional information
Reviewer Information Nature thanks K. Hazzard and D. Huse for their contribution to the peer review of this work.
Extended data figures and tables
Extended Data Figure 1 Mean-field solution of the phase diagram.
Order parameters α 1 and α 2 as a function of the pump–cavity detunings Δ 1 and Δ 2. The Raman coupling λ is fixed by the experimental value of the transverse pump lattice depth of 38ħω rec. The mean-field model includes cavity decay, different vacuum Rabi frequencies g i and the transverse pump potential.
Source data
Extended Data Figure 2 Lattice geometries for different choices of the phase ϕ of the transverse pump field for balanced cavity fields.
The atoms are cut into one-dimensional lines by the strong transverse pump field. On top, spatial distributions between triangular (ϕ = 0) and hexagonal (ϕ = π/2) can form through the interference between the cavity light fields and the transverse pump, depending on the phase ϕ of the latter.
Extended Data Figure 3 Dependence of the lattice structure on the cavity field amplitudes.
The ground-state manifold for equal couplings and detunings in is a circle in the space of the cavity fields α 1 and α 2. For each combination of fields, the interference potential in equation (3) between the transverse pump and cavity fields for ϕ = π/2 will have its minima at different positions. Following the circle clockwise, every second line moves left (top highlighted line) while the others move right (bottom highlighted line).
Extended Data Figure 4 Transition between discrete and continuous symmetries.
a–c, Histograms (normalized to unity area) of the angles θ describing the position of the crystal lattice, measured in the same way as the data in Fig. 4, but at Δ 1 = −2.1 MHz (a), Δ 1 = −2.2 MHz (b) and Δ 1 = −2.3 MHz (c). The grey lines show kernel density estimation analyses with a Gaussian kernel, whose bandwidth of 0.13π/2 was determined from a cross-validation maximum likelihood reconstruction. Each histogram consists of 19–49 realizations.
Source data
PowerPoint slides
Source data
Rights and permissions
About this article
Cite this article
Léonard, J., Morales, A., Zupancic, P. et al. Supersolid formation in a quantum gas breaking a continuous translational symmetry. Nature 543, 87–90 (2017). https://doi.org/10.1038/nature21067
-
Received:
-
Accepted:
-
Published:
-
Issue Date:
-
DOI : https://doi.org/10.1038/nature21067
This article is cited by
-
Crystallization of bosonic quantum Hall states in a rotating quantum gas
Nature (2022)
-
Discovery of quantum phases in the Shastry-Sutherland compound SrCu2(BO3)2 under extreme conditions of field and pressure
Nature Communications (2022)
-
Analysis of Shape Change of Droplet in Dipolar Bose–Hubbard Model
Journal of Low Temperature Physics (2022)
-
An optical lattice with sound
Nature (2021)
-
Self assembling cluster crystals from DNA based dendritic nanostructures
Nature Communications (2021)
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.
Source: https://www.nature.com/articles/nature21067
Publicar un comentario for "Supersolid Formation in a Quantum Gas Breaking Continuous Translational Symmetry"