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

Exact treatment of many body self-organization in a cavity.

Catalin-Mihai Halati, Ameneh Sheikhan, Helmut Ritsch, Corinna Kollath

Published Sep 16, 2019• 0 citations
OpenAlex

Abstract

We investigate the full quantum evolution of ultracold interacting bosonic atoms on a chain and coupled to an optical cavity. Extending the time-dependent matrix product state techniques to capture the global coupling to the cavity mode and the open nature of the cavity, we examine the long time behavior of the system beyond the mean-field elimination of the cavity field. We benchmark the newly developed method by computing the von Neumann entanglement entropy of the quantum trajectories. We investigate the many body steady states and the self-organization transition for a wide range of parameters. We show that in the self-organized phase the steady state consists in a mixture of the mean-field predicted density wave states and excited states with additional defects. For large dissipation strengths we develop a variant of the many-body adiabatic elimination technique and obtain a steady state with a fully mixed atomic sector. We observe numerically the crossover from the density wave state towards this mixed state.

Related papers

Numerically Exact Treatment of Many-Body Self-Organization in a Cavity

Catalin-Mihai Halati, Ameneh Sheikhan, Helmut Ritsch +1 more

We investigate the full quantum evolution of ultracold interacting bosonic atoms on a chain and coupled to an optical cavity. Extending the time-dependent matrix product state techniques and the many-body adiabatic elimination technique to capture the global coupling to the cavity mode and the open nature of the cavity, we examine the long time behavior of the system beyond the mean-field elimination of the cavity field. We investigate the many-body steady states and the self-organization transition for a wide range of parameters. We show that in the self-organized phase the steady state consists in a mixture of the mean-field predicted density wave states and excited states with additional defects. In particular, for large dissipation strengths a steady state with a fully mixed atomic sector is obtained crucially different from the predicted mean-field state.

arXiv:1909.07335•Physical Review Letters•Aug 28, 2020•42 citations

Theoretical methods to treat a single dissipative bosonic mode coupled globally to an interacting many-body system

Catalin-Mihai Halati, Ameneh Sheikhan, Corinna Kollath

We present two approaches capable of describing the dynamics of an interacting many-body system on a lattice coupled globally to a dissipative bosonic mode.Physical realizations are, for example, ultracold atom gases in optical lattice coupled to a photonic mode of an optical cavity or electronic gases in solids coupled to THz cavity fields.The first approach, applicable for large dissipation strengths and any system size, is a variant of the many-body adiabatic elimination method for investigating the long-time dynamics of the system.The second method extends the time-dependent matrix product techniques to capture the global coupling of the interacting particles to the bosonic mode and its open nature.It gives numerically exact results for small to intermediate system sizes.As a benchmark for our methods we perform the full quantum evolution of a Bose-Hubbard chain coupled to a cavity mode.We show that important deviations from the mean-field behavior occur when considering the full atoms cavity coupling [C.

arXiv:2004.11807•Physical Review Research•Nov 18, 2020•23 citations

Self-Organized Cavity Bosons beyond the Adiabatic Elimination Approximation

Giuliano Orso, Jakub Zakrzewski, Piotr Deuar

The longtime behavior of weakly interacting bosons moving in a two-dimensional optical lattice and coupled to a lossy cavity is investigated numerically via the truncated Wigner method, which allows us to take into full account the dynamics of the cavity mode, quantum fluctuations, cavity-boson correlations, and self-organization of individual runs. We first compare our results for small systems with quasi-exact calculations based on quantum trajectories, finding a remarkably good agreement for experimentally relevant boson fillings that improves further with system size. For large systems, we observe metastability at very long times and superfluid quasi-long range order, in sharp contrast with the true long range order found in the ground state of the approximate Bose-Hubbard model with extended interactions, obtained by adiabatically eliminating the cavity field. As the strength of the light-matter coupling increases, the system first becomes supersolid at the Dicke superradiant transition and then turns into a charge-density wave via the Berezinskii-Kosterlitz-Thouless mechanism. The two phase transitions are characterized via an accurate finite-size scaling analysis.

arXiv:2312.10502•Physical Review Letters•May 6, 2025•7 citations

Mott transition in a cavity-boson system: A quantitative comparison between theory and experiment

Rui Lin, Christoph Georges, Jens Klinder +6 more

The competition between short-range and cavity-mediated infinite-range interactions in a cavity-boson system leads to the existence of a superfluid phase and a Mott-insulator phase within the self-organized regime. In this work, we quantitatively compare the steady-state phase boundaries of this transition measured in experiments and simulated using the Multiconfigurational Time-Dependent Hartree Method for Indistinguishable Particles. To make the problem computationally feasible, we represent the full system by the exact many-body wave function of a two-dimensional four-well potential. We argue that the validity of this representation comes from the nature of both the cavity-atomic system and the Bose-Hubbard physics. Additionally, we show that the chosen representation only induces small systematic errors, and that the experimentally measured and theoretically predicted phase boundaries agree reasonably well. We thus demonstrate a new approach for the quantitative numerical modeling for the physics of the superfluid--Mott-insulator phase boundary.

arXiv:2104.11253•SciPost Physics•Aug 17, 2021•24 citations

Breaking strong symmetries in dissipative quantum systems: the (non-)interacting bosonic chain coupled to a cavity

Catalin-Mihai Halati, Ameneh Sheikhan, Corinna Kollath

In dissipative quantum systems, strong symmetries can lead to the existence of conservation laws and multiple steady states. The investigation of such strong symmetries and their consequences on the dynamics of the dissipative systems is still in its infancy. In this work we investigate a strong symmetry for bosonic atoms coupled to an optical cavity, an experimentally relevant system, using adiabatic elimination techniques and numerically exact matrix product state methods. We show the existence of multiple steady states for ideal bosons coupled to the cavity. We find that the introduction of a weak breaking of the strong symmetry by a small interaction term leads to a direct transition from multiple steady states to a unique steady state. We point out the phenomenon of dissipative freezing, the breaking of the conservation law at the level of individual realizations in the presence of the strong symmetry. For a weak breaking of the strong symmetry we see that the behavior of the individual trajectories still shows some signs of this dissipative freezing before it fades out for a larger symmetry breaking terms.

•Feb 4, 2021•7 citations

Ultracold bosons with cavity-mediated long-range interactions: A local mean-field analysis of the phase diagram

Astrid Elisa Niederle, Giovanna Morigi, Heiko Rieger

Ultracold bosonic atoms in optical lattices self-organize into a variety of structural and quantum phases when placed into a single-mode cavity and pumped by a laser. Cavity optomechanical effects induce an atom density modulation at the cavity-mode wavelength that competes with the optical lattice arrangement. Simultaneously short-range interactions via particle hopping promote superfluid order such that a variety of structural and quantum coherent phases can occur. We analyze the emerging phase diagram in two dimensions by means of an extended Bose-Hubbard model using a local mean-field approach combined with a superfluid cluster analysis. For commensurate ratios of the cavity and external lattice wavelengths, the Mott insulator-superfluid transition is modified by the appearance of charge density wave and supersolid phases, at which the atomic density supports the buildup of a cavity field. For incommensurate ratios, the optomechanical forces induce the formation of Bose-glass and superglass phases, namely, nonsuperfluid and superfluid phases, respectively, displaying quasiperiodic density modulations, which in addition can exhibit structural and superfluid stripe formation. The onset of such structures is constrained by the on-site interaction and is favorable at fractional densities. Experimental observables are identified and discussed.

arXiv:1606.00912•Physical Review A•Sep 7, 2016•62 citations
We investigate the full quantum evolution of ultracold interacting bosonic atoms on a chain and coupled to an optical cavity. Extending the time-dependent matrix product state techniques to capture the global coupling to the cavity mode and the open nature of the cavity, we examine the long time behavior of the system beyond the mean-field elimination of the cavity field. We benchmark the newly developed method by computing the von Neumann entanglement entropy of the quantum trajectories. We investigate the many body steady states and the self-organization transition for a wide range of parameters. We show that in the self-organized phase the steady state consists in a mixture of the mean-field predicted density wave states and excited states with additional defects. For large dissipation strengths we develop a variant of the many-body adiabatic elimination technique and obtain a steady state with a fully mixed atomic sector. We observe numerically the crossover from the density wave state towards this mixed state.
We investigate the full quantum evolution of ultracold interacting bosonic atoms on a chain and coupled to an optical cavity. Extending the time-dependent matrix product state techniques and the many-body adiabatic elimination technique to capture the global coupling to the cavity mode and the open nature of the cavity, we examine the long time behavior of the system beyond the mean-field elimination of the cavity field. We investigate the many-body steady states and the self-organization transition for a wide range of parameters. We show that in the self-organized phase the steady state consists in a mixture of the mean-field predicted density wave states and excited states with additional defects. In particular, for large dissipation strengths a steady state with a fully mixed atomic sector is obtained crucially different from the predicted mean-field state.
We present two approaches capable of describing the dynamics of an interacting many-body system on a lattice coupled globally to a dissipative bosonic mode.Physical realizations are, for example, ultracold atom gases in optical lattice coupled to a photonic mode of an optical cavity or electronic gases in solids coupled to THz cavity fields.The first approach, applicable for large dissipation strengths and any system size, is a variant of the many-body adiabatic elimination method for investigating the long-time dynamics of the system.The second method extends the time-dependent matrix product techniques to capture the global coupling of the interacting particles to the bosonic mode and its open nature.It gives numerically exact results for small to intermediate system sizes.As a benchmark for our methods we perform the full quantum evolution of a Bose-Hubbard chain coupled to a cavity mode.We show that important deviations from the mean-field behavior occur when considering the full atoms cavity coupling [C.
The longtime behavior of weakly interacting bosons moving in a two-dimensional optical lattice and coupled to a lossy cavity is investigated numerically via the truncated Wigner method, which allows us to take into full account the dynamics of the cavity mode, quantum fluctuations, cavity-boson correlations, and self-organization of individual runs. We first compare our results for small systems with quasi-exact calculations based on quantum trajectories, finding a remarkably good agreement for experimentally relevant boson fillings that improves further with system size. For large systems, we observe metastability at very long times and superfluid quasi-long range order, in sharp contrast with the true long range order found in the ground state of the approximate Bose-Hubbard model with extended interactions, obtained by adiabatically eliminating the cavity field. As the strength of the light-matter coupling increases, the system first becomes supersolid at the Dicke superradiant transition and then turns into a charge-density wave via the Berezinskii-Kosterlitz-Thouless mechanism. The two phase transitions are characterized via an accurate finite-size scaling analysis.
The competition between short-range and cavity-mediated infinite-range interactions in a cavity-boson system leads to the existence of a superfluid phase and a Mott-insulator phase within the self-organized regime. In this work, we quantitatively compare the steady-state phase boundaries of this transition measured in experiments and simulated using the Multiconfigurational Time-Dependent Hartree Method for Indistinguishable Particles. To make the problem computationally feasible, we represent the full system by the exact many-body wave function of a two-dimensional four-well potential. We argue that the validity of this representation comes from the nature of both the cavity-atomic system and the Bose-Hubbard physics. Additionally, we show that the chosen representation only induces small systematic errors, and that the experimentally measured and theoretically predicted phase boundaries agree reasonably well. We thus demonstrate a new approach for the quantitative numerical modeling for the physics of the superfluid--Mott-insulator phase boundary.
In dissipative quantum systems, strong symmetries can lead to the existence of conservation laws and multiple steady states. The investigation of such strong symmetries and their consequences on the dynamics of the dissipative systems is still in its infancy. In this work we investigate a strong symmetry for bosonic atoms coupled to an optical cavity, an experimentally relevant system, using adiabatic elimination techniques and numerically exact matrix product state methods. We show the existence of multiple steady states for ideal bosons coupled to the cavity. We find that the introduction of a weak breaking of the strong symmetry by a small interaction term leads to a direct transition from multiple steady states to a unique steady state. We point out the phenomenon of dissipative freezing, the breaking of the conservation law at the level of individual realizations in the presence of the strong symmetry. For a weak breaking of the strong symmetry we see that the behavior of the individual trajectories still shows some signs of this dissipative freezing before it fades out for a larger symmetry breaking terms.
Ultracold bosonic atoms in optical lattices self-organize into a variety of structural and quantum phases when placed into a single-mode cavity and pumped by a laser. Cavity optomechanical effects induce an atom density modulation at the cavity-mode wavelength that competes with the optical lattice arrangement. Simultaneously short-range interactions via particle hopping promote superfluid order such that a variety of structural and quantum coherent phases can occur. We analyze the emerging phase diagram in two dimensions by means of an extended Bose-Hubbard model using a local mean-field approach combined with a superfluid cluster analysis. For commensurate ratios of the cavity and external lattice wavelengths, the Mott insulator-superfluid transition is modified by the appearance of charge density wave and supersolid phases, at which the atomic density supports the buildup of a cavity field. For incommensurate ratios, the optomechanical forces induce the formation of Bose-glass and superglass phases, namely, nonsuperfluid and superfluid phases, respectively, displaying quasiperiodic density modulations, which in addition can exhibit structural and superfluid stripe formation. The onset of such structures is constrained by the on-site interaction and is favorable at fractional densities. Experimental observables are identified and discussed.