Generation of quantum light with tunable Wigner negativity with a semiconductor quantum dot

Hubert Lam; Petr Steindl; Yann Portella; Kiarn T. Laverick; Kian Hwee Lim; Juan R. Alvarez; Aristide Lemaitre; Maria Maffei; Alexia Auffeves; Dario A. Fioretto; Pascale Senellart

arXiv · 2610.36233

Generation of quantum light with tunable Wigner negativity with a semiconductor quantum dot

Hubert Lam·Petr Steindl·Yann Portella·Kiarn T. Laverick·Kian Hwee Lim·Juan R. Alvarez·Aristide Lemaitre·Maria Maffei·Alexia Auffeves·Dario A. Fioretto·Pascale Senellart

View original source ↗Read source document ↗Export metadata ↓

Abstract

Wigner-negative states of light are key resources for quantum advantage in continuous-variable optical quantum computing. They can be produced probabilistically via frequency conversion and photon detection, or deterministically by exploiting the single-photon nonlinearity of a quantum emitter. Here, we generate such Wigner-negative states of light with a tunable negativity using a single semiconductor quantum dot in a cavity. Optical coherent control of the quantum-dot transition allows to generate a quantum superposition of zero and one photon. The generated quantum states are characterized point-by-point in the phase space through homodyne measurement. The emergence of Wigner-function negativity is observed as the excitation power is increased. After correcting for collection and propagation losses, we obtain fidelities to the ideal state and quantum purities above 95%, together with near-optimal quadrature squeezing. The ability to generate a wide variety of Wigner-negative states with mature semiconductor technology opens promising opportunities for continuous-variable optical quantum technologies.

Explore related subjects

quant-ph cond-mat.mes-hall physics.optics

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Hubert Lam, Petr Steindl, Yann Portella, Kiarn T. Laverick, Kian Hwee Lim, Juan R. Alvarez, Aristide Lemaitre, Maria Maffei, Alexia Auffeves, Dario A. Fioretto, Pascale Senellart. 2026-10-26. Generation of quantum light with tunable Wigner negativity with a semiconductor quantum dot. https://arxiv.org/abs/2610.36233

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Robust Preparation of Bell States by Time Boundary Effect

Quantum entanglement is essential for modern quantum information processing. Entanglement gates convert initially non-entangled states into entangled ones by applying time-dependent parametric pulses. While Bell state preparation has been experimentally validated in various platforms, its stability and fidelity are constrained by environmental decoherence and parametric fluctuations. Here, we propose a dynamically robust method for preparing Bell states by leveraging the time boundary effect and momentum-space projective measurements within Su-Schrieffer-Heeger systems. Employing the Lindblad master equation, we theoretically demonstrate that the prepared Bell states exhibit remarkable robustness against both environmental decoherence and parametric time fluctuations, achieving nearly perfect quantum fidelity, with the momentum conservation law governing this robust behavior. This framework based on the time boundary effect is applicable to both fermionic and bosonic excitations, offering a unified paradigm for generating Bell states in quantum computation and communication.

quant-ph↗

arXiv2026

Emergent Quantum Synchronization Without Symmetry Breaking

Parametric amplification of a shared cavity mode turns the light--matter coupling phase of a two-ensemble Dicke model into a control parameter. We prove analytically that a cavity-set gain band opens a window of this phase with no static superradiant instability, leaving only a Hopf bifurcation, for arbitrary couplings, spin frequencies, damping rates and ensemble sizes. A $\mathbb{Z}_2$ parity keeps the quantum steady state unique and time independent: every order parameter vanishes and the oscillation lives in a slow parity-odd Liouvillian mode. Truncated-Wigner simulations, validated against exact ones, show that above threshold its quality factor grows linearly with system size and the ensembles phase lock; below threshold, both saturate. Quantum synchronization emerges without symmetry breaking and without requiring entanglement.

quant-ph↗

arXiv2026

Advantage of Sample Complexity in Quantum PAC Learning Requires Inverse Access to State-Preparation Unitaries

Whether quantum computation can reduce the amount of data required for conventional machine learning is a central problem in quantum machine learning. In probably approximately correct (PAC) learning, a learner receives training examples sampled from an unknown probability distribution. Quantum PAC learning extends this framework by allowing access to quantum examples, which are quantum states that coherently encode this distribution, or to unitaries that prepare quantum examples, with or without inverse access. When only copies of quantum examples are available, the optimal worst-case sample complexity asymptotically matches that of classical learning. In contrast, access to both a preparation unitary and its inverse can improve the accuracy dependence of query complexity. However, it has remained open whether access to the preparation unitary alone suffices for this improvement. In this work, we resolve this question by determining the optimal query complexity with forward-only access, taking the worst case over compatible preparation unitaries and their dimensions. In both realizable and agnostic PAC learning, this complexity matches, up to constant factors, the optimal sample complexity achievable with classical examples or copies of quantum examples. To prove these results, we construct, for any algorithm with forward-only access, a simulator that approximates the algorithm's Haar-averaged output state using as many copies of the prepared state as the algorithm makes queries. These results show that inverse access is essential for the known improvement in accuracy dependence in this worst-case setting. Beyond PAC learning, our reduction provides a general tool for transferring lower bounds for state copies to query lower bounds for forward-only access to the corresponding preparation unitaries.

quant-ph↗