Experiments towards a quantum information network with squeezed light and entanglement

Tamíris R. Calixto, Pablo L. Saldanha

F. J. Duarte

Shenchao Jin, Junlei Duan, Youwei Zhang +7 more

Squeezed spin states and squeezed light are both key resources for quantum metrology and quantum information science, but have been separately investigated in experiments so far. Simultaneous generation of these two types of quantum states in one experiment setup is intriguing but remains a challenging goal. Here, we propose a novel protocol based on judiciously engineered symmetric atom-light interaction, and report proof-of-principle experimental results of concurrent spin squeezing of 0.61±0.09 dB and light squeezing of 0.65_{-0.10}^{+0.11} dB in a hot atomic ensemble. The squeezing process is deterministic, yielding fixed squeezing directions for both the light field and the collective atomic spin. Furthermore, the squeezed light modes lie in the multiple frequency sidebands of a single spatial mode. This new type of dual squeezed state is applicable for quantum enhanced metrology and quantum networks. Our method can be extended to other quantum platforms such as optomechanics, cold atoms, and trapped ions.

F.J. Duarte

Zahra Shaterzadeh‐Yazdi, Peter S. Turner, Barry C. Sanders

Three-mode (tripartite) squeezed light is important for continuous variable quantum information tasks such as quantum teleportation, state sharing, and generating tripartite continuous variable entangled states, and furthermore is the first nontrivial step towards multipartite squeezed states. In such cases just one two-mode squeezer is used, and the squeezed light is distributed across multiple channels by passive optical elements. Here we show that these three-mode squeezed states are produced by optical networks that can be described as SU(1, 1) transformations, which enables relatively straightforward and elegant calculations of any output state from such squeezing networks for any input state.

Andrew G. White, Daniel F. V. James, William J. Munro +1 more