Tuning Wave-Particle Duality of Quantum Light by Generalized Photon Subtraction

TL;DR

This paper demonstrates a method to generate and control intermediate quantum states of light that bridge wave-like and particle-like behaviors, using generalized photon subtraction to enhance quantum computing resources.

Contribution

The authors experimentally implement generalized photon subtraction to tune quantum states of light, advancing the creation of non-Gaussian resources for optical quantum computing.

Findings

Achieved tunable control of wave-particle features in quantum light.

Generated high-rate spectral family of non-Gaussian states.

Enabled potential applications in fault-tolerant quantum computation.

Abstract

Wave--particle duality is a hallmark of quantum mechanics. For bosonic systems, there exists a continuum of intermediate states bridging wave-like Schr\"odinger cat states and particle-like Fock states. Such states have recently been recognized as valuable resources for enhancing fault-tolerant quantum computation (FTQC) with propagating light. Here we experimentally demonstrate tunable generation of these intermediate states by employing generalized photon subtraction (GPS). By detecting up to three photons from squeezed-light sources with a photon-number-resolving detector, we continuously control the balance between wave- and particle-like features. This approach allows us to construct a spectral family of quantum states with high generation rates, optimized according to the required fault-tolerance threshold. Our results establish GPS as a versatile toolbox for tailoring non-Gaussian resources, opening a pathway to efficient Gottesman--Kitaev--Preskill (GKP) qubit generation and addressing a central bottleneck in optical quantum computing.