2016/07/18 by Jean-Charles Forgues, Christian Lupien, Gabriel Gasse +1 · 1 citation
Computer Science · Physics and Astronomy · #Conductor #Materials science #Optics #Physics #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum optics and atomic interactions #Radiation #cond-mat.mes-hall
paper · pdf · doi:10.1016/j.crhy.2016.07.004
arXiv admin note: text overlap with arXiv:1410.0552
openalex publication_date 2016/07/18 · arxiv created 2016/12/19 · arxiv updated 2016/12/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report experimental evidence that the microwave electromagnetic field generated by a normal conductor, here a tunnel junction placed at ultra-low temperature, can be non-classical. By measuring the quadratures of the electromagnetic field at one or two frequencies in the GHz range, we demonstrate the existence of squeezing as well as entanglement in such radiation. In one experiment, we observe that the variance of one quadrature of the photo-assisted noise generated by the junction goes below its vacuum level. In the second experiment, we demonstrate the existence of correlations between the quadratures taken at two frequencies, which can be stronger than allowed by classical mechanics, proving that the radiation at those two frequencies are entangled. 1