Temporal trapping: a route to strong coupling and deterministic optical quantum computation

TL;DR

This paper introduces a novel dispersion-engineered temporal trapping method that enhances nonlinear interactions in photonic structures, enabling deterministic quantum gates at room temperature, a significant step toward scalable optical quantum computing.

Contribution

The paper presents a new temporal confinement technique using a 'flying cavity' to achieve strong coupling in nanophotonics, overcoming previous loss-confinement limitations.

Findings

Temporal trapping enhances nonlinear interaction by at least an order of magnitude.

Numerical simulations show high-fidelity deterministic quantum gates are feasible.

Near-term platforms can achieve strong coupling with realistic dispersion and loss parameters.

Abstract

The realization of deterministic photon-photon gates is a central goal in optical quantum computation and engineering. A longstanding challenge is that optical nonlinearities in scalable, room-temperature material platforms are too weak to achieve the required strong coupling, due to the critical loss-confinement tradeoff in existing photonic structures. In this work, we introduce a novel confinement method, dispersion-engineered temporal trapping, to circumvent the tradeoff, paving a route to all-optical strong coupling. Temporal confinement is imposed by an auxiliary trap pulse via cross-phase modulation, which, combined with the spatial confinement of a waveguide, creates a "flying cavity" that enhances the nonlinear interaction strength by at least an order of magnitude. Numerical simulations confirm that temporal trapping confines the multimode nonlinear dynamics to a single-mode subspace, enabling high-fidelity deterministic quantum gate operations. With realistic dispersion engineering and loss figures, we show that temporally trapped ultrashort pulses could achieve strong coupling on near-term nonlinear nanophotonic platforms. Our results highlight the potential of ultrafast nonlinear optics to become the first scalable, high-bandwidth, and room-temperature platform that achieves a strong coupling, opening a new path to quantum computing, simulation, and light sources.