The effects of spacetime geometry on quantum systems are typically very small. Here, we demonstrate a coherent many-body mechanism that can enhance these effects. We show that, in an ordered array, a gravitational wave induces long-range all-to-all dissipative coupling among atoms within half the gravitational wavelength. This coupling is mediated by the electromagnetic vacuum and leads to cooperative photon emission that we term gravitational wave-induced photon superradiance--delayed and intense emission of photons at frequencies shifted from the atomic transition by the gravitational wave frequency. The phenomenon arises in a regime distinct from flat-spacetime superradiance, allowing gravitational effects to dominate the collective photon emission from atoms. It persists despite common experimental challenges in atom arrays such as position disorder and partial filling. We thus identify a new class of effects arising from the interplay of general relativity and collective quantum optics that individual atoms do not exhibit, and demonstrate that engineered quantum many-body systems provide a new window into the interface of general relativity and quantum mechanics.
The effects of spacetime geometry on quantum systems are typically very small. Here, we demonstrate a coherent many-body mechanism that can enhance these effects. We show that, in an ordered array, a gravitational wave induces long-range all-to-all dissipative coupling among atoms within half the gravitational wavelength. This coupling is mediated by the electromagnetic vacuum and leads to cooperative photon emission that we term gravitational wave-induced photon superradiance--delayed and intense emission of photons at frequencies shifted from the atomic transition by the gravitational wave frequency. The phenomenon arises in a regime distinct from flat-spacetime superradiance, allowing gravitational effects to dominate the collective photon emission from atoms. It persists despite common experimental challenges in atom arrays such as position disorder and partial filling. We thus identify a new class of effects arising from the interplay of general relativity and collective quantum optics that individual atoms do not exhibit, and demonstrate that engineered quantum many-body systems provide a new window into the interface of general relativity and quantum mechanics.
When quantum emitters couple indistinguishably to light, they can synchronize into a collective light matter system with radiative properties profoundly different from those of independent particles. To date, the resulting collective effects have largely been confined to point like or homogeneous ensembles. Here, we open access to a qualitatively new collective regime by realizing geometrically ordered, spatially extended atom arrays with subwavelength spacing. This establishes a fundamentally new platform in which collective emission is no longer confined to a single Dicke mode but instead emerges from an ordered network of photon mediated interactions. We find that 2D atom arrays undergo strong super and subradiant emission. Despite subwavelength spacing, we achieve site resolved imaging and directly observe the buildup of spatial correlations, demonstrating the transformation of cooperative decay into a strongly correlated many-body process. We observe extensive scaling of superradiance, uncover superradiant revivals, and reveal the ferromagnetic nature of superradiance and the antiferromagnetic nature of subradiance. Our results realize a novel programmable platform for exploring and utilizing dissipative many-body quantum physics, opening new possibilities for photon capture, storage, and atom photon entanglement.
We investigate the collective spontaneous emission of ordered atomic arrays in the presence of external magnetic fields and generalized gravitational backgrounds. In this case, within a unified theoretical framework, the influence of magnetic interactions in cooperative radiative processes is analyzed through modified transition dynamics and collective coupling effects between interacting atoms. Also, the formalism includes generalized gravitational contributions to the emission process, permitting the evaluation of curvature-dependent phase corrections and their combined influence with magnetic-field interactions. Moreover, the collective emission spectrum is obtained through an eikonal reduction procedure, where both the gravitational phase and magnetic coupling modify the spectral profile and coherence characteristics of the emitted radiation. In addition, the many-body transition amplitude and generalized structure factor are constructed to describe cooperative quantum interference and correlation effects in interacting atomic configurations. In this case, the results demonstrate that external magnetic fields and gravitational backgrounds generate observable corrections in collective decay channels, spectral line profiles, and coherence properties within atomic arrays. In this context, these results establish a generalized formulation of cooperative quantum emission in environments where electromagnetic and gravitational interactions coexist, with applications to quantum optics, precision spectroscopy, relativistic quantum systems, and field-dependent collective atomic platforms.
The coherent emission of multiple atoms gives rise to superradiance, a cornerstone phenomenon in quantum optics with wide-ranging applications in quantum information processing and precision metrology. Despite its importance, how the superradiant scaling with respect to the number of participating atoms can be effectively controlled remains largely unexplored. In this work, we investigate a cavity-QED system and demonstrate that atom-photon coupling can significantly alter the emission behavior--suppressing the collective superradiant scaling while enhancing the scaling associated with individual atomic emissions. Our study provides a pathway toward controllable collective emission in state-of-the-art experimental platforms.
This thesis examines how atomic quantum systems can be utilized to probe spacetime effects in regimes where quantum mechanics and general relativity intersect, and how gravitational phenomena imprint on experimentally accessible observables. The work is based on two complementary studies. In Article I, we propose an experimental scheme that combines trapped-atom interferometry with Ramsey interrogation to realize a clock held in a spatial superposition at two heights in Earth’s gravitational field. Using a path-integral treatment of interferometric phases and incorporating the internal-energy contribution to mass, we derive leading relativistic corrections and identify two signatures of proper-time superposition: (i) oscillations of interferometric visibility and (ii) an effective shift of the clock transition frequency. We argue that this frequency-shift signature may be within reach of current or near-term technology, even when visibility changes are too small to resolve. In Article II, we develop a general framework for spontaneous emission in curved spacetime and apply it to a gravitational-wave background. We demonstrate that gravitational waves can induce spectral sidebands and directional modulations in the emitted radiation, and formulate parameter estimation via Fisher-information-based sensitivity bounds, yielding order-of-magnitude requirements for detectability under idealized measurement conditions.
In inverted atomic ensembles, photon-mediated interactions give rise to Dicke superradiance, a form of many-body decay that results in a rapid release of energy as a photon burst. While originally studied in pointlike ensembles, this phenomenon persists in extended ordered systems if the interparticle distance is below a certain bound. Here, we investigate Dicke superradiance in a realistic experimental setting using ordered arrays of alkaline-earth(-like) atoms, such as strontium and ytterbium. Such atoms offer exciting new opportunities for light-matter interactions, as their internal structure allows for trapping at short interatomic distances compared to their long-wavelength transitions, providing the potential for collectively enhanced dissipative interactions. Despite their intricate electronic structure, we show that two-dimensional arrays of these atomic species should exhibit many-body superradiance for achievable lattice constants. Moreover, superradiance effectively “closes” transitions, such that multilevel atoms become more two-level like. This occurs because the avalanchelike decay funnels the emission of most photons into the dominant transition, overcoming the single-atom decay ratios dictated by their fine structure and Zeeman branching. Our work represents an important step in harnessing alkaline-earth atoms as quantum optical sources and as platforms to explore many-body dissipative dynamics. Published by the American Physical Society 2024
When atoms are coupled to a common electromagnetic environment, the exchange of photons through dipole-dipole interactions leads to the emergence of cooperative effects. As a particular example, superradiance arises from spontaneous emission when this exchange leads to constructive interference of the emitted photons. Here, we introduce an integrated method for studying cooperative radiation in many-body systems. This method, which allows to study extended systems with arbitrarily large number of particles, can be formulated by an effective, nonlinear, two-atom master equation that describes the dynamics using a closed form which treats single- and many-body terms on an equal footing. We apply this method to a homogeneous gas of initially inverted two-level atoms, and demonstrate the appearance of both superradiance and subradiance, identifying a many-body coherence term as the source of these cooperative effects. We describe the many-body induced broadening -- which is analytically found to scale with the optical depth of the system -- and light shifts, and distinguish spontaneous effects from induced ones. In addition, we theoretically predict the time-dependence of subradiance, and the phase change of the radiated field during the cooperative decay.