Entanglement-enhanced probing of a delicate material system

Quantum metrology uses entanglement and other quantum effects to improve the sensitivity of demanding measurements. Probing of delicate systems demands high sensitivity from limited probe energy and has motivated the field's key benchmark-the standard quantum limit. Here we report the first entanglement-enhanced measurement of a delicate material system. We non-destructively probe an atomic spin ensemble by means of near-resonant Faraday rotation, a measurement that is limited by probe-induced scattering in quantum-memory and spin-squeezing applications. We use narrowband, atom-resonant NOON states to beat the standard quantum limit of sensitivity by more than five standard deviations, both on a per-photon and per-damage basis. This demonstrates quantum enhancement with fully realistic loss and noise, including variable-loss effects. The experiment opens the way to ultra-gentle probing of single atoms, single molecules, quantum gases and living cells.Comment: 7 pages, 8 figures; Nature Photonics, advance online publication, 16 December 201

Expeditious Synthesis of New 3,4,6-Trihydroxythiepanes from d-(-)-Quinic Acid

[[abstract]]We report herein that the new seven-membered-ring thiosugars (thiepanes) have been synthesized from d-(-)-quinic acid. The key feature of the synthesis involves the thiocyclization of protected hexane-1,2,3,5,6-pentanol derivatives. The subsequent step of acidic removal of protecting groups is critical in the reaction conditions to obtain the required 3,4,6-trihydroxythiepanes. During the course of studies, the unexpected trihydroxythiopyrans are formed because of the ring contractions of their corresponding trihydroxythiepanes under various conditions.[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]US