Valery Simonyan | Searcharxiv

arXiv2026

Hamiltonian spectra in quantum computers through the generalized eigenvalue method

Quantum computers can generate real-time correlators of field theories. By adapting the generalized eigenvalue problem to these correlators, energy eigenvalues can be extracted directly. The method is tested using both classical simulations and quantum hardware, successfully resolving several low-lying energy levels in agreement with exact diagonalization. Comparison with an alternative spectrum determination based on the Fourier transform of correlators shows that the proposed approach is substantially more efficient.

quant-ph↗

arXiv2023

Chiral Flat-Band Optical Cavity with Atomically Thin Mirrors

A fundamental requirement for photonic technologies is the ability to control the confinement and propagation of light. Widely utilized platforms include two-dimensional (2D) optical microcavities in which electromagnetic waves are confined between either metallic or distributed Bragg reflectors. Recently, transition metal dichalcogenides hosting tightly bound excitons with high optical quality have emerged as promising atomically thin mirrors. In this work, we propose and experimentally demonstrate a sub-wavelength 2D nano-cavity using two atomically thin mirrors with degenerate resonances. Angle-resolved measurements show a flat band, which sets this system apart from conventional photonic cavities. Remarkably, we demonstrate how the excitonic nature of the mirrors enables the formation of chiral and tunable optical modes upon the application of an external magnetic field. Moreover, we show the electrical tunability of the confined mode. Our work demonstrates a mechanism for confining light with high-quality excitonic materials, opening perspectives for spin-photon interfaces, and chiral cavity electrodynamics.

physics.optics↗