Optical Cavity Advances Superradiant Phase Transition in Two-Component Bose-Einstein Condensate

The behaviour of Bose-Einstein condensates within optical cavities is revealing new insights into fundamental physics, and a recent study explores the complex interplay of phase transitions and atomic properties within these systems. Jia-Ying Lin, Wei Qin, and Renyuan Liao, all from the College of Physics and Energy at Fujian Normal University, investigated a two-component condensate subjected to a transverse pump laser. Their work demonstrates a unique phase diagram, significantly different from single-component systems, driven by the characteristics of the red-detuned component. This research is important because it reveals spontaneous phase separation and a superfluid-to-lattice supersolid transition, potentially paving the way for advancements in areas like quantum simulation and optical switching.

Researchers combined perturbation theory with extensive numerical simulations to map the phase transition, demonstrating its dominance by the red-detuned component and revealing a phase diagram markedly different from single-component systems. This work pioneered a method for inducing spontaneous phase separation between the two condensate components, observable as alternating stripe patterns in the normal phase and distinct Bragg gratings emerging in the superradiant phase.

To achieve these results, the team solved the driven-dissipative dynamics of the atom-cavity system using a Gross-Pitaevski-like equation, employing an imaginary time propagation method to obtain stationary states. The researchers carefully discriminated between normal and superradiant phases by examining the cavity photon field order parameter, having first replaced a parameter α with a specific equation and evaluated the integral within each time evolution step. Further analysis involved decomposing the order parameter Θ into components θj, allowing scientists to track their evolution as a function of the tuning parameter V0.

The simultaneous occurrence of atomic self-organized pattern formation and the superradiant phase transition was confirmed by observing finite values of both α and θj, with opposing signs for θ1 and θ2 indicating spatial separation of the two components. Visualisation of density modulations revealed alternate stripe patterns in the normal phase and Bragg gratings in the superradiant phase, providing direct evidence of the phase transition. Detailed spectral analysis, derived by considering deviations from the steady state and linearizing the governing equations, identified roton-type mode softening, signifying a transition from a superfluid to a lattice supersolid phase.

Two-Component BEC Superradiance and Phase Separation Scientists have

Scientists have demonstrated a novel superradiant phase transition within a two-component Bose-Einstein condensate, meticulously investigating the interplay between distinct atomic detunings. The research reveals a phase diagram markedly different from single-component systems, driven by components confined within an optical cavity and stimulated by a transverse pump laser. Experiments show a spontaneous phase separation occurring between the two condensate components, visually manifesting as alternating stripe patterns in the normal phase and the formation of distinct Bragg gratings when the system enters the superradiant phase.

The team measured the Bogoliubov excitation spectrum, revealing a critical softening of roton-type modes, a key indicator of a superfluid-to-lattice supersolid transition. Detailed calculations of ground-state structures and critical behaviours established that the red-detuned component dominates the phase transition process. The work meticulously maps out the phase diagrams, identifying the dominant factors driving the transition and demonstrating a natural separation between the two condensate components as tuning parameters are varied.

Specifically, component one experiences an attractive pump potential with a negative detuning, while component two experiences a repulsive potential with a positive detuning. The theoretical framework incorporates the optical potentials generated by both the pump beam and the cavity field. Further analysis of the system’s dynamics reveals the influence of the effective cavity detuning and the density order parameter Θ. This breakthrough delivers insights into the complex interplay between atomic detunings and collective phenomena, potentially enabling advancements in areas such as quantum simulation and the development of novel optical switching technologies.

Red Detuning Drives Superradiant Phase Separation Superradiance in

This research details an investigation into superradiance within a two-component Bose-Einstein condensate, exploring how differing atomic detunings influence the phase transition. Through a combination of perturbation theory and numerical simulations, the authors demonstrate that the red-detuned component dominates the process, leading to a phase diagram markedly different from that observed in single-component systems. The condensate exhibits spontaneous phase separation, evidenced by the formation of alternating stripe patterns in the normal phase and distinct Bragg gratings when superradiance occurs.

Furthermore, analysis of the Bogoliubov excitation spectrum revealed a softening of roton-type modes, suggesting the phase transition also represents a transition to a superfluid-to-lattice supersolid state. This finding highlights a complex interplay between atomic detunings and collective phenomena, potentially opening avenues for applications in areas like simulation technologies and optical switching. The authors acknowledge limitations inherent in the mean-field approach used to generate the initial phase diagrams, noting the emergence of an unstable region due to diverging ground-state energy.

The study establishes a clear link between the relative atomic detunings and the resulting phase behaviour, demonstrating that the system sustains superradiance to higher lattice depths than a blue-detuned single-component condensate. Future work could focus on exploring the detailed dynamics of these driven-dissipative atom-cavity systems and refining the understanding of the observed instabilities through more advanced theoretical modelling. These results contribute a nuanced understanding of multi-component Bose-Einstein condensates and their behaviour within optical cavities.

The behaviour of Bose-Einstein condensates within optical cavities is revealing new insights into fundamental physics, and a recent study explores the complex interplay of phase transitions and atomic properties within these systems. Their work demonstrates a unique phase diagram, potentially paving the way for advancements in areas like quantum simulation and optical switching. This research is important because it reveals spontaneous phase separation and a superfluid-to-lattice supersolid transition.