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Polaritonic Bloch's Theorem beyond the Long-Wavelength Approximation
Authors:
Giovanna Bruno,
Rosario Roberto Riso,
Henrik Koch,
Enrico Ronca
Abstract:
Cavity quantum electrodynamics provides a powerful tool to manipulate material properties, yet it remains a matter of debate whether and how quantized fields affect the periodicity of crystals. Here, we extend Bloch's theorem to crystals under strong light-matter coupling, revealing that polariton quasiparticles preserve lattice periodicity. We introduce a general framework to incorporate multimod…
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Cavity quantum electrodynamics provides a powerful tool to manipulate material properties, yet it remains a matter of debate whether and how quantized fields affect the periodicity of crystals. Here, we extend Bloch's theorem to crystals under strong light-matter coupling, revealing that polariton quasiparticles preserve lattice periodicity. We introduce a general framework to incorporate multimode cavity fields in a simple and tractable way, showing that additional modes contribute small energy corrections noticeable only at low frequencies. Within the single-photon approximation, these contributions reduce to a spatially uniform effective field in the crystal plane, providing a formal justification for the single-mode and long-wavelength approximations commonly used in molecular polaritonics. Together, these results establish a rigorous framework for describing polaritonic states in crystalline solids.
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Submitted 13 January, 2026; v1 submitted 17 December, 2025;
originally announced December 2025.
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Collective Strong Coupling Modifies Aggregation and Solvation
Authors:
Matteo Castagnola,
Tor S. Haugland,
Enrico Ronca,
Henrik Koch,
Christian Schäfer
Abstract:
Intermolecular interactions are pivotal for aggregation, solvation, and crystallization. We demonstrate that the collective strong coupling of several molecules to a single optical mode results in notable changes in the molecular excitations around an impurity, e.g., in the first aggregation or solvation shell. A competition between short-range Coulombic and long-range photonic correlation inverts…
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Intermolecular interactions are pivotal for aggregation, solvation, and crystallization. We demonstrate that the collective strong coupling of several molecules to a single optical mode results in notable changes in the molecular excitations around an impurity, e.g., in the first aggregation or solvation shell. A competition between short-range Coulombic and long-range photonic correlation inverts the local transition density in a polaritonic state, suggesting notable changes in the polarizability of the solvation shell. Our results provide an alternative perspective on recent work in polaritonic chemistry and pave the way for the rigorous treatment of cooperative effects in aggregation, solvation, and crystallization.
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Submitted 14 December, 2023;
originally announced December 2023.
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Two-Dimensional Moiré Polaronic Electron Crystals
Authors:
Eric A. Arsenault,
Yiliu Li,
Birui Yang,
Xi Wang,
Heonjoon Park,
Edoardo Mosconi,
Enrico Ronca,
Takashi Taniguchi,
Kenji Watanabe,
Daniel Gamelin,
Andrew Millis,
Cory R. Dean,
Filippo de Angelis,
Xiaodong Xu,
X. -Y. Zhu
Abstract:
Two-dimensional moiré materials have emerged as the most versatile platforms for realizing quantum phases of electrons. Here, we explore the stability origins of correlated states in WSe2/WS2 moiré superlattices. We find that ultrafast electronic excitation leads to melting of the Mott states on time scales five times longer than predictions from the charge hopping integrals and the melting rates…
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Two-dimensional moiré materials have emerged as the most versatile platforms for realizing quantum phases of electrons. Here, we explore the stability origins of correlated states in WSe2/WS2 moiré superlattices. We find that ultrafast electronic excitation leads to melting of the Mott states on time scales five times longer than predictions from the charge hopping integrals and the melting rates are thermally activated, with activation energies of 18 and 13 meV for the one- and two-hole Mott states, respectively, suggesting significant electron-phonon coupling. DFT calculation of the one-hole Mott state confirms polaron formation and yields a hole-polaron binding energy of 16 meV. These findings reveal a close interplay of electron-electron and electron-phonon interactions in stabilizing the polaronic Mott insulators at transition metal dichalcogenide moiré interfaces.
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Submitted 2 March, 2024; v1 submitted 31 July, 2023;
originally announced July 2023.
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Ground-state properties of the hydrogen chain: insulator-to-metal transition, dimerization, and magnetic phases
Authors:
Mario Motta,
Claudio Genovese,
Fengjie Ma,
Zhi-Hao Cui,
Randy Sawaya,
Garnet Kin-Lic Chan,
Natalia Chepiga,
Phillip Helms,
Carlos Jimenez-Hoyos,
Andrew J. Millis,
Ushnish Ray,
Enrico Ronca,
Hao Shi,
Sandro Sorella,
Edwin M. Stoudenmire,
Steven R. White,
Shiwei Zhang
Abstract:
Accurate and predictive computations of the quantum-mechanical behavior of many interacting electrons in realistic atomic environments are critical for the theoretical design of materials with desired properties, and require solving the grand-challenge problem of the many-electron Schrodinger equation. An infinite chain of equispaced hydrogen atoms is perhaps the simplest realistic model for a bul…
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Accurate and predictive computations of the quantum-mechanical behavior of many interacting electrons in realistic atomic environments are critical for the theoretical design of materials with desired properties, and require solving the grand-challenge problem of the many-electron Schrodinger equation. An infinite chain of equispaced hydrogen atoms is perhaps the simplest realistic model for a bulk material, embodying several central themes of modern condensed matter physics and chemistry, while retaining a connection to the paradigmatic Hubbard model. Here we report a combined application of cutting-edge computational methods to determine the properties of the hydrogen chain in its quantum-mechanical ground state. Varying the separation between the nuclei leads to a rich phase diagram, including a Mott phase with quasi long-range antiferromagnetic order, electron density dimerization with power-law correlations, an insulator-to-metal transition and an intricate set of intertwined magnetic orders.
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Submitted 13 July, 2020; v1 submitted 4 November, 2019;
originally announced November 2019.
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Cavity Quantum-Electrodynamical Chern Insulator: Route Towards Light-Induced Quantized Anomalous Hall Effect in Graphene
Authors:
Xiao Wang,
Enrico Ronca,
Michael A. Sentef
Abstract:
We show that an energy gap is induced in graphene by light-matter coupling to a circularly polarized photon mode in a cavity. Using many-body perturbation theory we compute the electronic spectra which exhibit photon-dressed sidebands akin to Floquet sidebands for laser-driven materials. In contrast with Floquet topological insulators, in which a strictly quantized Hall response is induced by ligh…
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We show that an energy gap is induced in graphene by light-matter coupling to a circularly polarized photon mode in a cavity. Using many-body perturbation theory we compute the electronic spectra which exhibit photon-dressed sidebands akin to Floquet sidebands for laser-driven materials. In contrast with Floquet topological insulators, in which a strictly quantized Hall response is induced by light only for off-resonant driving in the high-frequency limit, the photon-dressed Dirac fermions in the cavity show a quantized Hall response characterized by an integer Chern number. Specifically for graphene we predict that a Hall conductance of $2 e^2/h$ can be induced in the low-temperature limit.
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Submitted 8 May, 2019; v1 submitted 1 March, 2019;
originally announced March 2019.
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Cavity control of Excitons in two dimensional Materials
Authors:
Simone Latini,
Enrico Ronca,
Umberto de Giovannini,
Hannes Hübener,
Angel Rubio
Abstract:
We propose a robust and efficient way of controlling the optical spectra of two-dimensional materials and van der Waals heterostructures by quantum cavity embedding. The cavity light-matter coupling leads to the formation of exciton-polaritons, a superposition of photons and excitons. Our first principles study demonstrates a reordering and mixing of bright and dark excitons spectral features and…
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We propose a robust and efficient way of controlling the optical spectra of two-dimensional materials and van der Waals heterostructures by quantum cavity embedding. The cavity light-matter coupling leads to the formation of exciton-polaritons, a superposition of photons and excitons. Our first principles study demonstrates a reordering and mixing of bright and dark excitons spectral features and in the case of a type II van-der-Waals heterostructure an inversion of intra and interlayer excitonic resonances. We further show that the cavity light-matter coupling strongly depends on the dielectric environment and can be controlled by encapsulating the active 2D crystal in another dielectric material. Our theoretical calculations are based on a newly developed non-perturbative many-body framework to solve the coupled electron-photon Schrödinger equation in a quantum-electrodynamical extension of the Bethe-Salpeter approach. This approach enables the ab-initio simulations of exciton-polariton states and their dispersion from weak to strong cavity light-matter coupling regimes. Our method is then extended to treat van der Waals heterostructures and encapsulated 2D materials using a simplified Mott-Wannier description of the excitons that can be applied to very large systems beyond reach for fully ab-initio approaches.
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Submitted 5 May, 2019; v1 submitted 5 October, 2018;
originally announced October 2018.
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Time-step targeting time-dependent and dynamical density matrix renormalization group algorithms with ab initio Hamiltonians
Authors:
Enrico Ronca,
Zhendong Li,
Carlos A. Jimenez-Hoyos,
Garnet Kin-Lic Chan
Abstract:
We study the dynamical density matrix renormalization group (DDMRG) and time-dependent density matrix renormalization group (td-DMRG) algorithms in the ab initio context, to compute dynamical correlation functions of correlated systems. We analyze the strengths and weaknesses of the two methods in small model problems, and propose two simple improved formulations, DDMRG$^{++}$ and td-DMRG$^{++}$,…
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We study the dynamical density matrix renormalization group (DDMRG) and time-dependent density matrix renormalization group (td-DMRG) algorithms in the ab initio context, to compute dynamical correlation functions of correlated systems. We analyze the strengths and weaknesses of the two methods in small model problems, and propose two simple improved formulations, DDMRG$^{++}$ and td-DMRG$^{++}$, that give increased accuracy at the same bond dimension, at a nominal increase in cost. We apply DDMRG$^{++}$ to obtain the oxygen core-excitation energy in the water molecule in a quadruple-zeta quality basis, which allows us to estimate the remaining correlation error in existing coupled cluster results. Further, we use DDMRG$^{++}$ to compute the local density of states and gaps, and td-DMRG$^{++}$ to compute the complex polarization function, in linear hydrogen chains with up to 50 H atoms, to study metallicity and delocalization as a function of bond-length.
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Submitted 28 September, 2017; v1 submitted 28 June, 2017;
originally announced June 2017.
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Spectral Functions of the Uniform Electron Gas via Coupled-Cluster Theory and Comparison to the $GW$ and Related Approximations
Authors:
James McClain,
Johannes Lischner,
Thomas Watson,
Devin A. Matthews,
Enrico Ronca,
Steven G. Louie,
Timothy C. Berkelbach,
Garnet Kin-Lic Chan
Abstract:
We use, for the first time, ab initio coupled-cluster theory to compute the spectral function of the uniform electron gas at a Wigner-Seitz radius of $r_\mathrm{s}=4$. The coupled-cluster approximations we employ go significantly beyond the diagrammatic content of state-of-the-art $GW$ theory. We compare our calculations extensively to $GW$ and $GW$-plus-cumulant theory, illustrating the strengths…
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We use, for the first time, ab initio coupled-cluster theory to compute the spectral function of the uniform electron gas at a Wigner-Seitz radius of $r_\mathrm{s}=4$. The coupled-cluster approximations we employ go significantly beyond the diagrammatic content of state-of-the-art $GW$ theory. We compare our calculations extensively to $GW$ and $GW$-plus-cumulant theory, illustrating the strengths and weaknesses of these methods in capturing the quasiparticle and satellite features of the electron gas. Our accurate calculations further allow us to address the long-standing debate over the occupied bandwidth of metallic sodium. Our findings indicate that the future application of coupled-cluster theory to condensed phase material spectra is highly promising.
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Submitted 28 December, 2015; v1 submitted 14 December, 2015;
originally announced December 2015.