Cavity-Enhanced Collective Quantum Processing with Polarization-Encoded Qubits

TL;DR

This paper proposes a cavity-enhanced optical system for collective quantum processing, encoding qubits in polarization modes, enabling universal gates with feasible experimental parameters.

Contribution

It introduces a novel cavity-based architecture that separates physical and logical qubits, utilizing polarization encoding and nonlinear interactions for scalable quantum computing.

Findings

Order-unity conditional phases achievable in centimeter-scale cavities.

The architecture does not require extreme nonlinear coefficients or ultra-stable lasers.

The system provides a plausible platform for cavity-based collective quantum architectures.

Abstract

We introduce a cavity-enhanced optical architecture for collective quantum processing in which logical qubits are encoded in the polarization subspace of recirculating intracavity modes. The physical carrier and computational degree of freedom are explicitly separated: harmonic cavity bundles provide a stable resonant substrate, while programmable polarization transformations implement single-qubit operations. A polarization-selective nonlinear interaction in the entanglement region generates tunable controlled-phase gates, enabling a universal gate set. A parameter-scaling analysis shows that order-unity conditional phases are attainable in centimeter-scale cavities using experimentally accessible solid-state nonlinear media, without requiring extreme nonlinear coefficients, millisecond photon lifetimes, or sub-hertz laser stabilization. The results indicate that resonant recirculation provides a physically plausible platform for cavity based collective quantum architectures.