# Stabilisation of an optical transition energy via nuclear Zeno dynamics in quantum dot-cavity systems

## TL;DR

This paper demonstrates how quantum Zeno dynamics can stabilize the optical transition energy in quantum dot-cavity systems by using photon scattering as a nuclear spin measurement, affecting photon correlations.

## Contribution

It introduces a theoretical framework showing how photon scattering induces nuclear Zeno effects, stabilizing the optical resonance in quantum dot-cavity systems.

## Key findings

- Photon scattering acts as a nuclear spin measurement.
- Quantum Zeno effect inhibits nuclear spin dynamics.
- Photon autocorrelation changes with laser intensity.

## Abstract

We investigate the effect of nuclear spins on the phase shift and polarisation rotation of photons scattered off a quantum dot-cavity system. We show that as the phase shift depends strongly on the resonance energy of an electronic transition in the quantum dot, it can provide a sensitive probe of the quantum state of nuclear spins that broaden this transition energy. By including the electron-nuclear spin coupling at a Hamiltonian level within an extended input-output formalism, we show how a photon scattering event acts as a nuclear spin measurement, which when rapidly applied leads to an inhibition of the nuclear spin dynamics via the quantum Zeno effect, and a corresponding stabilisation of the optical resonance. We show how such an effect manifests in the intensity autocorrelation $g^{(2)}(\tau)$ of scattered photons, whose long-time bunching behaviour changes from quadratic decay for low photon scattering rates (weak laser intensities), to ever slower exponential decay for increasing laser intensities as optical measurements impede the nuclear spin evolution.