arXiv subjects

Marco Vallone

Publications and source records attributed to Marco Vallone.

3 recordsLinked to original sources

arXiv2026

Non-secular polariton leakage and dark-state protection in hybrid plasmonic cavities

A major issue in exploiting plasmonic cavities as key components in nanotechnology is the effect of radiative and absorption losses on their electrodynamic behavior. Treating them as open-systems, we derive a time-local, completely positive master equation that retains non-secular interference between decay pathways and reduces to the standard secular description when the environment resolves polariton splitting. When it does not, the theory predicts order-one deviations from secular leakage dynamics, including bath-induced coherences and stabilization of dark polaritons, and provides a simple design criterion based on the ratio of polariton splitting to reservoir linewidth. A time-resolved leakage measurement, such as transmission, reflectivity, or photoluminescence, can be used to observe these effects.

physics.optics↗

arXiv2025

Quantum open system description of a hybrid plasmonic cavity

We present a unified quantum open system framework for lossy plasmonic cavities in which coherent dynamics, relaxation, dephasing, and irreversible absorption are treated on equal footing. The Dyson equation for the cavity photon propagator in the random-phase approximation yields a complex self-energy S that accounts for both the renormalization and the damping of hybrid plasmon-photon modes (polaritons, in a quasi-particle description). Tracing out the electronic and photonic environments leads to a Liouvillian for the upper (UP) and lower (LP) polaritonic branches, incorporating leakage through the imaginary part of the self-energy, internal UP-LP scattering rates, and dephasing. Time evolution equations for polariton populations, interbranch coherence, and driven amplitudes in closed form also provide analytic expressions for their steady-state values, the quench rate of UP-LP oscillations and polaritonic lineshapes, valid in the limit of low polaritonic density, but covering light-matter ultrastrong coupling. The theory establishes a self-consistent description of dissipative polariton dynamics in plasmonic and nanophotonic cavities, directly applicable to response spectra, time-domain measurements, and dissipation engineering.

physics.optics↗

arXiv2019

Higgs and Goldstone modes in crystalline solids

In crystalline solids the acoustic phonon is known to be the frequency-gapless Goldstone boson emerging from the spontaneous breaking of the continuous Galilean symmetry induced by the crystal lattice. It has also been described as the gauge boson that appears when the free electrons' Lagrangian in the crystal is requested to be locally gauge invariant with respect to T(3), the group of the infinitesimal spatial translations. However, the non-Abelianity of T(3) makes the acoustic phonon a frequency-gapped mode, in contradiction with its description as Goldstone boson. A different perspective overcomes this contradiction. In fact, we show that both the acoustic and optical phonon - the latter never appearing following the other two approaches - emerge respectively as the gapless Goldstone (phase) and the gapped Higgs (amplitude) fluctuation mode of an order parameter arising from the spontaneous breaking of a global symmetry, without invoking the gauge principle. The optical phonon's frequency-gap is present in all regimes, and it arises from a mass-like term in the Lagrangian due to the Higgs mechanism itself. Instead, an eventual acoustic phonon's frequency-gap appears only in the strong nonlinear regime, and it is due to an anharmonic term, the same term arising from the gauging of T(3), an approach which did not provide any description of the optical phonon, though. In addition, the Higgs mechanism describes all the phonon-phonon interactions, including a possible perturbation on the acoustic phonon's frequency dispersion relation induced by the eventual optical phonon, a peculiar behavior not described so far in these terms.

cond-mat.stat-mech↗