# Entanglement with negative Wigner function of almost 3,000 atoms heralded by one photon

@article{McConnell2015EntanglementWN,
title={Entanglement with negative Wigner function of almost 3,000 atoms heralded by one photon},
author={Robert McConnell and Hao Zhang and Jiazhong Hu and Senka {\'C}uk and Vladan Vuleti{\'c}},
journal={Nature},
year={2015},
volume={519},
pages={439-442}
}
• Published 25 March 2015
• Physics
• Nature
Quantum-mechanically correlated (entangled) states of many particles are of interest in quantum information, quantum computing and quantum metrology. Metrologically useful entangled states of large atomic ensembles have been experimentally realized, but these states display Gaussian spin distribution functions with a non-negative Wigner quasiprobability distribution function. Non-Gaussian entangled states have been produced in small ensembles of ions, and very recently in large atomic ensembles…
170 Citations
• Physics
• 2016
Quantum-mechanically correlated (entangled) states of many particles are of interest in quantum information, quantum computing and quantum metrology. Metrologically useful entangled states of large
Analysis of the interaction between a photon and an ensemble of some 3,000 atoms trapped between two mirrors has revealed a form of multi-atom quantum entanglement that has no counterpart in
• Physics
Nature Communications
• 2017
An entanglement witness is developed for quantifying the number of genuinely entangled particles based on the collective effect of directed emission combined with the non-classical nature of the emitted light to demonstrate 16 million genuinely entangled atoms in a solid-state quantum memory prepared by the heralded absorption of a single photon.
• Physics
Reviews of Modern Physics
• 2018
Quantum technologies exploit entanglement to revolutionize computing, measurements, and communications. This has stimulated the research in different areas of physics to engineer and manipulate
• Physics
npj Quantum Information
• 2021
Quantum theory does not prevent entanglement from being created and observed in macroscopic physical systems, in reality however, the accessible scale of entanglement is still very limited due to
• Physics
npj Quantum Information
• 2021
Quantum theory does not prevent entanglement from being created and observed in macroscopic physical systems, in reality however, the accessible scale of entanglement is still very limited due to
• Physics
Physical review letters
• 2018
This scheme, together with population measurements, provides a fully optical determination of the amount of entanglement and large sensitivity of the interference phase evolution points to applications of the presented scheme in high-precision gradient sensing.
• Physics
Nature Communications
• 2017
This work creates a Dicke state in a solid by storing a single photon in a crystal that contains many large atomic ensembles with distinct resonance frequencies and derives a lower bound for the number of entangled ensemble based on the contrast of the interference and the single-photon character of the input.
• Physics
Physical review letters
• 2022
Multipartite entangled states are significant resources for both quantum information processing and quantum metrology. In particular, non-Gaussian entangled states are predicted to achieve a higher
• Physics
Physical Review X
• 2018
We observe collective quantum spin states of an ensemble of atoms in a one-dimensional light-atom interface. Strings of hundreds of cesium atoms trapped in the evanescent fiel of a tapered nanofiber

## References

SHOWING 1-10 OF 37 REFERENCES

• Physics
Science
• 2014
A general method is developed to extract the Fisher information, which reveals that the quantum dynamics of a classically unstable system creates quantum states that are not spin squeezed but nevertheless entangled, which quantifies metrologically useful entanglement.
• Physics
Science
• 2014
Using atom chips and fiber-optical cavities, a method based on nondestructive collective measurement and conditional evolution is developed to create symmetric entangled states and perform their tomography, which demonstrates creation and analysis of entangled states with mean atom numbers up to 41 and experimentally prove multiparticle entanglement.
• Physics
Nature
• 2005
The creation of cat states of up to six atomic qubits is reported, which represents the current state-of-the-art for large entangled states in any qubit system.
• Physics
Proceedings of the National Academy of Sciences
• 2009
There is an optimal degree of decoherence induced by the quantum measurement which maximizes the generated entanglement, and a 2-color QND scheme used in this paper is shown to have a number of advantages for entanglements generation as compared with a single- color QND measurement.
• Physics
Science
• 2013
Coherently Controlling Large Cats The control and manipulation of quantum information based on superconducting circuits is an attractive route because of the possibility of scale-up. Vlastakis et al.
• Physics
Nature
• 2010
Measurement-induced entanglement stored in four atomic memories; user-controlled, coherent transfer of the atomicEntanglement to four photonic channels; and characterization of the full quadripartite entangler using quantum uncertainty relations are demonstrated.
• Physics
Physical review letters
• 2014
The authors' criterion proves that a Dicke-like state using spin dynamics in a Bose-Einstein condensate contains at least genuine 28-particle entanglement, and infer a generalized squeezing parameter of -11.4(5)  dB.
• Physics
• 2014
We report on the observation of quantum interference of a collective single spin excitation with a spin ensemble of $N_{\text{atom}} =10^5$ atoms. Detection of a single photon scattered from the
• Physics
Nature
• 2010
It is shown experimentally that the classical precision limit can be surpassed using nonlinear atom interferometry with a Bose–Einstein condensate and the results provide information on the many-particle quantum state, and imply the entanglement of 170 atoms.
• Physics
• 2013
We present a proposal and a feasibility study for the creation and quantum state tomography of a single polariton state of an atomic ensemble. The collective non-classical and non-Gaussian state of