arXiv subjects

Charlie-Ray Mann

Publications and source records attributed to Charlie-Ray Mann.

8 recordsLinked to original sources

arXiv2026

Structured Non-Locality and Emergent Locality in Cavity-QED Many-Body Dynamics

Cavity quantum electrodynamics (QED) modifies many-body systems by combining cavity-mediated collective interactions with microscopic short-range interactions. The resulting dynamics lies between the local and fully collective limits, such that neither locality nor collectivity alone provides a complete organizing principle. In the clean conceptual limit of dominant collective coupling, we show that the effective dynamics within each energetically isolated subspace is generically controlled by whether that subspace admits a local product-state basis, and identify exceptions imposed by angular-momentum selection rules. Product-state subspaces generically retain the spatial structure of the microscopic interaction. Entangled subspaces instead generically dress local processes with global operators, generating non-local but highly structured dynamics. We illustrate this by deriving the corresponding effective Hamiltonians in two representative cavity-QED spin models. The cavity-isolated subspace thus becomes a resource for generating competing short-range interactions or globally conditioned local processes, opening a class of many-body dynamics without local or fully collective counterparts.

quant-ph↗

arXiv2025

Squeezing Classical Antiferromagnets into Quantum Spin Liquids via Global Cavity Fluctuations

Cavity quantum electrodynamics with atomic ensembles is typically associated with collective spin phenomena, such as superradiance and spin squeezing, in which the atoms evolve collectively as a macroscopic spin ($S\sim N/2$) on the Bloch sphere. Surprisingly, we show that the tendency toward a collective spin description need not imply collective spin phenomena; rather, it can be exploited to generate new forms of strongly correlated quantum matter. The key idea is to use uniform cavity-mediated interactions to energetically project the system into the total-spin singlet sector ($S=0$) - a highly entangled subspace where the physics is governed entirely by cavity fluctuations. Focusing on Rydberg atom arrays coupled to a single-mode cavity, we show that global cavity fluctuations can effectively squeeze classical antiferromagnets into quantum spin liquids, characterized by non-local entanglement, fractionalized excitations, and emergent gauge fields. This work suggests that cavity QED can be a surprising resource for inducing strongly correlated phenomena, which could be explored in the new generation of hybrid tweezer-cavity platforms.

quant-ph↗

arXiv2024

Metalens formed by structured arrays of atomic emitters

Arrays of atomic emitters have proven to be a promising platform to manipulate and engineer optical properties, due to their efficient cooperative response to near-resonant light. Here, we theoretically investigate their use as an efficient metalens. We show that, by spatially tailoring the (sub-wavelength) lattice constants of three consecutive two-dimensional arrays of identical atomic emitters, one can realize a large transmission coefficient with arbitrary position-dependent phase shift, whose robustness against losses is enhanced by the collective response. To characterize the efficiency of this atomic metalens, we perform large-scale numerical simulations involving a substantial number of atoms ($N\sim 5\times 10^5$) that is considerably larger than comparable works. Our results suggest that low-loss, robust optical devices with complex functionalities, ranging from metasurfaces to computer-generated holograms, could be potentially assembled from properly engineered arrays of atomic emitters.

quant-ph↗

arXiv2024

Selective Radiance in Super-Wavelength Atomic Arrays

A novel way to create efficient atom-light interfaces is to engineer collective atomic states that selectively radiate into a target optical mode by suppressing emission into undesired modes through destructive interference. While it is generally assumed that this approach requires dense atomic arrays with sub-wavelength lattice constants, here we show that selective radiance can also be achieved in arrays with super-wavelength spacing. By stacking multiple two-dimensional arrays we find super-wavelength mirror configurations where one can eliminate emission into unwanted diffraction orders while enhancing emission into the desired specular mode, leading to near-perfect reflection of weak resonant light. These super-wavelength arrays can also be functionalized into efficient quantum memories, with error probabilities on the order of ~1 for a trilayer with only around ~100 atoms per layer. Relaxing the previous constraint of sub-wavelength spacing could potentially ease the technical requirements for realizing efficient atom-light interfaces, such as enabling the use of tweezer arrays.

quant-ph↗

arXiv2020

Topological transitions induced by cavity-mediated interactions in photonic valley-Hall metasurfaces

Topological phases of light exhibit unique properties beyond the realm of conventional photonics. In particular the valley-Hall topological insulator has been realized in a variety of photonic structures because it can be easily induced by breaking certain lattice symmetries. However, the valley-Chern numbers are usually fixed by design and the corresponding topological edge states are forced to propagate in a fixed direction. Here, we propose a mechanism to induce topological transitions via accidental Dirac points in metasurfaces composed of interacting dipole emitters/antennas. For a fixed arrangement of dipoles, we show that the topological phase depends critically on the surrounding electromagnetic environment which mediates the dipole-dipole interactions. To access different topological phases we embed the metasurface inside a cavity waveguide where one can tune the dominant dipolar coupling from short-range Coulomb interactions to long-range photon-mediated interactions by reducing the cavity width; this results in a topological transition characterized by an inversion of the valley-Chern numbers. Consequently, we show that one can switch the chirality of the topological edge states by modifying only the electromagnetic environment in which the dipoles are embedded. This mechanism could have important implications for other topological phases such as photonic higher-order topological insulators.

physics.optics↗

arXiv2020

Tunable pseudo-magnetic fields for polaritons in strained metasurfaces

Artificial magnetic fields are revolutionizing our ability to manipulate neutral particles, by enabling the emulation of exotic phenomena once thought to be exclusive to charged particles. In particular, pseudo-magnetic fields generated by nonuniform strain in artificial lattices have attracted considerable interest because of their simple geometrical origin. However, to date, these strain-induced pseudo-magnetic fields have failed to emulate the tunability of real magnetic fields because they are dictated solely by the strain configuration. Here, we overcome this apparent limitation for polaritons supported by strained metasurfaces, which can be realized with classical dipole antennas or quantum dipole emitters. Without altering the strain configuration, we unveil how one can tune the pseudo-magnetic field by modifying the electromagnetic environment via an enclosing photonic cavity which modifies the nature of the interactions between the dipoles. Remarkably, due to the competition between short-range Coulomb interactions and long-range photon-mediated interactions, we find that the pseudo-magnetic field can be entirely switched off at a critical cavity height for any strain configuration. Consequently, by varying only the cavity height, we demonstrate a tunable Lorentz-like force that can be switched on/off and an unprecedented collapse and revival of polariton Landau levels. Unlocking this tunable pseudo-magnetism for the first time poses new intriguing questions beyond the paradigm of conventional tight-binding physics.

physics.optics↗

arXiv2018

Manipulating type-I and type-II Dirac polaritons in cavity-embedded honeycomb metasurfaces

Pseudorelativistic Dirac quasiparticles have emerged in a plethora of artificial graphene systems that mimic the underlying honeycomb symmetry of graphene. However, it is notoriously difficult to manipulate their properties without modifying the lattice structure. Here we theoretically investigate polaritons supported by honeycomb metasurfaces and, despite the trivial nature of the resonant elements, we unveil rich Dirac physics stemming from a non-trivial winding in the light-matter interaction. The metasurfaces simultaneously exhibit two distinct species of massless Dirac polaritons, namely type-I and type-II. By modifying only the photonic environment via an enclosing cavity, one can manipulate the location of the type-II Dirac points, leading to qualitatively different polariton phases. This enables one to alter the fundamental properties of the emergent Dirac polaritons while preserving the lattice structure - a unique scenario which has no analog in real or artificial graphene systems. Exploiting the photonic environment will thus give rise to unexplored Dirac physics at the subwavelength scale.

physics.optics↗

arXiv2018

Plasmon polaritons in cubic lattices of spherical metallic nanoparticles

We theoretically investigate plasmon polaritons in cubic lattices of spherical metallic nanoparticles. The nanoparticles, each supporting triply-degenerate localized surface plasmons, couple through the Coulomb dipole-dipole interaction, giving rise to collective plasmons that extend over the whole metamaterial. The latter hybridize with photons forming plasmon polaritons, which are the hybrid light-matter eigenmodes of the system. We derive general analytical expressions to evaluate both plasmon and plasmon-polariton dispersions, and the corresponding eigenstates. These are obtained within a Hamiltonian formalism, which takes into account retardation effects in the dipolar interaction between the nanoparticles and considers the dielectric properties of the nanoparticles as well as their surrounding. Within this model we predict polaritonic splittings in the near-infrared to the visible range of the electromagnetic spectrum that depend on polarization, lattice symmetry and wavevector direction. Finally, we show that the predictions of our model are in excellent quantitative agreement with conventional finite-difference frequency-domain simulations, but with the advantages of analytical insight and significantly reduced computational cost.

cond-mat.mes-hall↗