Conventional descriptions of light in materials rely on macroscopic models that average the optical response over the microscopic lattice structures. These models are deployed in the semi-classical limit, where the collective local response over many lattice sites is adequate. However, they fail to capture the full spatial dispersion, which requires a lattice-resolved description of light. We address this limitation by formulating a deep-microscopic nonlocal theory of the photon based on the Maxwell Hamiltonian and its characteristic equation. The solution reveals the full spatial dispersion in the form of deep-microscopic photonic bandstructure, and corresponding real-space Bloch field textures. We demonstrate our theory for a two-dimensional (2D) tight-binding model of a gapped honeycomb lattice. Our framework thus extends photons to the same microscopic footing as electrons or phonons, providing a unified route to studying topology, dissipation, and quantum fluctuations of light in dispersive materials.
AI Summary
The paper addresses how to describe electromagnetic modes in a periodic material when spatial dispersion and lattice-scale field variations cannot be captured by a macroscopic dielectric function. It formulates a reciprocal-space Maxwell eigenproblem in which a frequency-dependent microscopic response matrix couples field components at momenta $\mathbf q+\mathbf G$. Electronic-band current matrix elements supply the nonlocal susceptibility, and Bloch-mode coefficients specify the corresponding real-space fields.
The example is a two-band honeycomb tight-binding model with nearest-neighbor hopping $t=2.7$ eV, complex next-nearest-neighbor hopping $t_2=0.15$ eV and phase $\pi/3$, and sublattice mass $m=0.5$ eV. The stated electronic gap is approximately $0.55$ eV. The calculation reduces the Maxwell equations to a transverse, frequency-dependent dielectric eigenproblem. Fitting each dielectric-matrix element to an effective Lorentz oscillator permits an auxiliary-variable formulation as a generalized linear eigenproblem. The stated implementation retains seven reciprocal vectors, giving a $28\times28$ eigenproblem at each momentum along $\Gamma$–$K$–$M$–$\Gamma$.
A single fitted pole per matrix element is reported to capture photonic bands up to approximately $6$ eV; higher energies or more complex materials may require additional poles. Other stated approximations include nonmagnetic response, negligible magnetoelectric coupling, reciprocal-space truncation, and phenomenological broadening of $0.05$–$0.1$ eV. The supplied text describes numerical procedures but provides no quantitative photonic dispersions, field-texture results, fit residuals, or convergence tests. Topology and quantum fluctuations are identified as prospective applications rather than calculated outcomes.
Almost certainly largely AI-generatedOverclaimsUnclear noveltyMissing comparisonPossible error
Central claim may not hold: The supplied paper provides neither the claimed calculated bands and field textures nor convergence and fitting evidence supporting its advertised full-spatial-dispersion demonstration.
The central transverse eigenproblem incorrectly discards longitudinal electric fields despite allowing longitudinal–transverse dielectric mixing, omitting the resulting Schur-complement correction.
The displayed auxiliary-variable matrices fail direct substitution tests, and the claimed fixed-size quartic linearization does not generally accommodate distinct pole denominators for individual response elements.
The vacuum Maxwell matrix construction contradicts its own component equations and mixes Gaussian-unit field conventions inconsistently.
The decay-sign interpretation is reversed, and the stated mode-filtering criterion risks excluding physical passive modes.
Written by gpt-6.1-sol from the paper's full text. Automated: it can be wrong.
Conventional descriptions of light in materials rely on macroscopic models that average the optical response over the microscopic lattice structures. These models are deployed in the semi-classical limit, where the collective local response over many lattice sites is adequate. However, they fail to capture the full spatial dispersion, which requires a lattice-resolved description of light. We address this limitation by formulating a deep-microscopic nonlocal theory of the photon based on the Maxwell Hamiltonian and its characteristic equation. The solution reveals the full spatial dispersion in the form of deep-microscopic photonic bandstructure, and corresponding real-space Bloch field textures. We demonstrate our theory for a two-dimensional (2D) tight-binding model of a gapped honeycomb lattice. Our framework thus extends photons to the same microscopic footing as electrons or phonons, providing a unified route to studying topology, dissipation, and quantum fluctuations of light in dispersive materials.
The paper addresses how to describe electromagnetic modes in a periodic material when spatial dispersion and lattice-scale field variations cannot be captured by a macroscopic dielectric function. It formulates a reciprocal-space Maxwell eigenproblem in which a frequency-dependent microscopic response matrix couples field components at momenta q+G. Electronic-band current matrix elements supply the nonlocal susceptibility, and Bloch-mode coefficients specify the corresponding real-space fields.
The example is a two-band honeycomb tight-binding model with nearest-neighbor hopping t=2.7 eV, complex next-nearest-neighbor hopping t2=0.15 eV and phase π/3, and sublattice mass m=0.5 eV. The stated electronic gap is approximately 0.55 eV. The calculation reduces the Maxwell equations to a transverse, frequency-dependent dielectric eigenproblem. Fitting each dielectric-matrix element to an effective Lorentz oscillator permits an auxiliary-variable formulation as a generalized linear eigenproblem. The stated implementation retains seven reciprocal vectors, giving a 28×28 eigenproblem at each momentum along Γ–K–M–Γ.
A single fitted pole per matrix element is reported to capture photonic bands up to approximately 6 eV; higher energies or more complex materials may require additional poles. Other stated approximations include nonmagnetic response, negligible magnetoelectric coupling, reciprocal-space truncation, and phenomenological broadening of 0.05–0.1 eV. The supplied text describes numerical procedures but provides no quantitative photonic dispersions, field-texture results, fit residuals, or convergence tests. Topology and quantum fluctuations are identified as prospective applications rather than calculated outcomes.
Recent advances are enabling quantum emitters to interact with photonic crystals, whose electromagnetic modes exhibit complex dispersion relations, spatial mode structure, and polarization textures. However, modeling light-matter behavior in these systems faces a persistent trade-off: electromagnetic approaches based on Maxwell-equation solvers provide realistic vectorial descriptions but are difficult to integrate with quantum many-body and non-perturbative methods, whereas simplified quantum-optical lattice models are tractable but typically rely on scalar and spatially independent light-matter couplings that miss essential features of these structured photonic environments. Here, we introduce a constructive framework to derive quantum-optical lattice descriptions that overcome this trade-off. Combining symmetry-constrained tight-binding constructions with numerically computed photonic band structures and field profiles, our method yields minimal, symmetry-enforced lattice Hamiltonians that reproduce the target photonic dispersion while retaining the mode-resolved (position- and polarization-dependent) structure of the light-matter coupling. We show that these models recover Green's-function-based emitter dynamics in the perturbative regime, while providing access to non-perturbative quantum dynamical simulations beyond emitter-only descriptions. As a proof of principle, we apply the framework to a two-dimensional photonic crystal and show that it captures polarization-dependent directional emission inaccessible to scalar models, while enabling the analysis of non-Markovian light-matter dynamics and entanglement. Our results provide a practical bridge between classical electromagnetic simulation tools and quantum-optical many-body and non-Markovian modeling in photonic crystal settings.
Quantum light-matter interactions, described by the theory of quantum electrodynamics (QED), have motivated numerous scientific discoveries and technological developments over the past few decades. Considerable effort has been made to develop different QED platforms, e.g., free space, waveguides, cavities, and photonic crystals, for engineering quantum light-matter interactions. This thesis explores a new frontier, deep microscopic QED, which leverages the deep microscopic response of materials to reveal new topological, quantum, and thermal photonic phenomena with applications to quantum sensing and information processing. In the first part of this thesis, we investigate unique topological photonic effects arising in the deep microscopic QED regime. Previous efforts focused on topological photonic phases and edge states arising from artificial spatial structures of materials (e.g., photonic crystals or metamaterials). One fundamental question is whether topological photonic states can also arise from the intrinsic response of many-body systems and do not rely on materials' macroscopic structures. Here, we first discuss a new topological electromagnetic phase - ‘optical N-phase’ arising in two-dimensional (2D) viscous hydrodynamic electrons in graphene, which originates from the microscopic response of 2D materials and does not rely on materials' macroscopic structures. We then introduce the associated edge states, optical N-plasmons, which are topologically protected ultra-subwavelength edge magneto-plasmons. We further show how these topological plasmons can be harnessed to design chiral radio-frequency nonreciprocal circuit components, topological hydrodynamic circulators, that interface quantum and classical hardware.In the second part of this thesis, we focus on collective atom-photon interactions in the deep microscopic QED regime. In atom interactions with photonic environments, there exist two non-unitary processes -- pure dephasing and spontaneous emission. Despite considerable interest in collective effects in spontaneous emission since the 1950s, one long-standing problem is whether collective effects in pure dephasing can arise in atom-photon interactions. This question is particularly important in the quantum information era since pure dephasing is the main obstacle in current quantum information technologies. Here, we first introduce a new collective quantum phenomenon, ‘nanophotonic superdephasing,’ occurring in atom/spin ensembles in nanoscale photonic environments. This nanophotonic superdephasing phenomenon originates from low-frequency photonic environment correlations, and leads to collectively accelerated disentanglement without photon emission, in stark contrast to conventional collective spontaneous emission/superradiance effects. We further reveal the effects of nanophotonic environment mediated correlated dynamics on quantum computing and sensing. We demonstrate that correlations of nanoscale EM environments in spin qubit quantum computing devices can induce correlated errors and limit quantum gate fidelity. Meanwhile, based on nanophotonic collective dephasing, we also propose a multiqubit quantum sensing protocol that exploits spatially correlated noise near materials to enable order parameter symmetry characterization of materials beyond single-qubit methods.In the final part, we explore thermal photonic phenomena in the deep microscopic regime. Conventional techniques in engineering near-field radiative heat transfer typically rely on phonons, plasmons, and electromagnetic modes in structured materials. Here, we reveal a new approach to enhance near-field thermal radiation: leveraging intrinsic quantum coherence in superconducting materials. We reveal the quantum fingerprint of superconductivity in thermal photonics, ‘superconducting coherence peak’ in near-field thermal radiation, which originates from quantum coherence of Bogoliubov quasiparticles, with potential applications in thermal engineering in superconducting circuits.Overall, the thesis establishes a deep microscopic QED platform for new quantum, topological, and thermal photonic phenomena in many-body systems, with applications in quantum sensors and devices.
We theoretically study quantum-optical properties of one- and two-dimensional semiconductor nanostructures, where the electronic band structure is described by a two-band tight-binding model. Since the focus of our work is on analyzing quantum-optical effects of systems with a continuous band structure, many-body processes like electron-electron and electron-phonon interactions are neglected. The quantum-optical interband excitations are fully incorporated and described by a Jaynes-Cummings-type model. The exciting quantum light can be a state with arbitrary photon statistics. For simplicity, the results discussed here are limited to single-photon and two-photon Fock states. Our analytical approach is based on the eigenvalue problem and can be utilized to obtain explicit expressions for the steady-state properties of the system. Numerical simulations are based on solutions of the equations of motion and allow for a more precise analysis of the dynamics and nonresonant excitations of the system. We demonstrate that during the interaction process, a collective excitation of the conduction band is formed. For nonresonant excitations, this collective dynamics results in interesting steady states, in which the resonantly addressed eigenstates are occupied. The presented model provides a framework for microscopic simulations of quantum-optically excited extended semiconductor nanostructures.
These notes, intended to be self contained and tutorial, present a direct, macroscopic approach to quantizing light inside a linear-response dielectric material when both spectral dispersion and spatial nonuniformity are present, but the spectral region of interest is optically transparent so that explicit treatment of the underlying physics of the medium is not needed. The approach taken is based on the macroscopic Maxwell equations and a corresponding Hamiltonian, without the use of Lagrangians or any dynamical model for the medium, and uses a standard mode-based quantization method. The treatment covers: energy density and flux in a dispersive dielectric; a summary of the inverse permittivity formalism; a new derivation of the mode normalization condition; a direct proof of the nonorthogonality of the modes; examples of quantized field expressions for the general case and various special cases; the relationship between group velocity and energy flux; the band approximation and the continuum limit; and quantum optical treatment of waveguide modes.
Exciton-polaritons, hybrid light-matter quasiparticles formed when a material interacts with a confined electric field, have experimentally been shown to exhibit mesoscale coherent quantum propagation that remains robust at room temperature. However, an accurate and direct quantum dynamical simulation of this phenomenon that does not resort to semi-classical approximations is prohibitively expensive computationally, limiting the microscopic understanding of the rich dynamical interplay among phonons, photons, and electrons under collective light-matter coupling. To address this fundamental challenge, we develop a non-Markovian master equation approach which enables the fully quantum mechanical simulation of non-equilibrium exciton-polariton dynamics and captures phonon-induced decoherence and dissipation beyond the conventional Markovian limit. To carry out this task, a procedure is developed in which the wave vector space is coarse-grained and each diagonal element of the density matrix is evolved in parallel. To demonstrate the utility of this approach, we simulate exciton-polariton transport in TIPS-pentacene. We find that our approach reasonably captures the experimentally observed renormalization of the polariton group velocity, which originates from the phonon-induced non-Markovian Lamb shift. We further show that this renormalization cannot be reproduced within conventional Markovian theories.
We theoretically demonstrate the population switching of quantum dots (QD's), modeled as two-level atoms in idealized one-dimensional (1D) and two-dimensional (2D) photonic crystals (PC's) by self-consistent solution of the Maxwell-Bloch equations. In our semiclassical theory, energy states of the electron are quantized, and electron dynamics is described by the atomic Bloch equation, while electromagnetic waves satisfy the classical Maxwell equations. Near a waveguide cutoff in a photonic band gap, the local electromagnetic density of states (LDOS) and spontaneous emission rates exhibit abrupt changes with frequency, enabling large QD population inversion driven by both continuous and pulsed optical fields. We recapture and generalize this ultrafast population switching using the Maxwell-Bloch equations. Radiative emission from the QD is obtained directly from the surrounding PC geometry using finite-difference time-domain simulation of the electromagnetic field. The atomic Bloch equations provide a source term for the electromagnetic field. The total electromagnetic field, consisting of the external input and radiated field, drives the polarization components of the atomic Bloch vector. We also include a microscopic model for phonon dephasing of the atomic polarization and nonradiative decay caused by damped phonons. Our self-consistent theory captures stimulated emission and coherent feedback effects of the atomic Mollow sidebands, neglected in earlier treatments. This leads to remarkable high-contrast QD-population switching with relatively modest (factor of 10) jump discontinuities in the electromagnetic LDOS. Switching is demonstrated in three separate models of QD's placed (i) in the vicinity of a band edge of a 1D PC, (ii) near a cutoff frequency in a bimodal waveguide channel of a 2D PC, and (iii) in the vicinity of a localized defect mode side coupled to a single-mode waveguide channel in a 2D PC.