Electric field intensity measurement by using doublet electromagnetically induced transparency of cold Rb Rydberg atoms

We demonstrate a simple method to measure electric field intensity by using doublet electromagnetically induced transparency(EIT) spectra of cold Rb Rydberg atoms, where the frequency of the coupling laser does not need to be locked. Based on the Stark splitting of the Rb Rydberg state, 10D_(3/2), under electric fields and the corresponding calculated polarizabilities, the real electric field intensity is calculated using the difference in radio-frequency diffraction between two acousto-optic modulators, which acts as a frequency criterion that allows us to measure the electrical field without locking the coupling laser. The value measured by this simple method shows a good agreement with our previous work [Opt.Express 29 1558(2021)] where the frequency of the coupling laser needs to be locked with an additional EIT spectrum based on atom vapor and a proportional–integral–differential feedback circuit. Our presented method can also be extended to the measurement of electric field based on hot Rydberg atom vapor, which has application in industry.

A multi-band atomic candle with microwave-dressed Rydberg atoms

Stabilizing important physical quantities to atom-based standards lies at the heart of modern atomic,molecular and optical physics,and is widely applied to the field of precision metrology.Of particular importance is the atom-based microwave field amplitude stabilizer,the so-called atomic candle.Previous atomic candles are realized with atoms in their ground state,and hence suffer from the lack of frequency band tunability and small stabilization bandwidth,severely limiting their development and potential applications.To tackle these limitations,we employ microwave-dressed Rydberg atoms to realize a novel atomic candle that features multi-band frequency tunability and large stabilization bandwidth.We demonstrate amplitude stabilization of microwave field from C-band to Ka-band,which could be extended to quasi-DC and terahertz fields by exploring abundant Rydberg levels.Our atomic candle achieves stabilization bandwidth of 100 Hz,outperforming previous ones by more than two orders of magnitude.Our simulation indicates the stabilization bandwidth can be further increased up to 100 kHz.Our work paves a route to develop novel electric field control and applications with a noise-resilient,miniaturized,sensitive and broadband atomic candle.

Effect of inferior vena cava respiratory variability-guided fluid therapy after laparoscopic hepatectomy:a randomized controlled clinical trial

Background:After major liver resection,the volume status of patients is still undetermined.However,few concerns have been raised about postoperative fluid management.We aimed to compare gut function recovery and short-term prognosis of the patients after laparoscopic liver resection(LLR)with or without inferior vena cava(IVC)respiratory variability-directed fluid therapy in the anesthesia intensive care unit(AICU).Methods:This randomized controlled clinical trial enrolled 70 patients undergoing LLR.The IVC respiratory variability was used to optimize fluid management of the intervention group in AICU,while the standard practice of fluid management was used for the control group.The primary outcome was the time to flatus after surgery.The secondary outcomes included other indicators of gut function recovery after surgery,postoperative length of hospital stay(LOS),liver and kidney function,the severity of oxidative stress,and the incidence of severe complications associated with hepatectomy.Results:Compared with patients receiving standard fluid management,patients in the intervention group had a shorter time to anal exhaust after surgery(1.5±0.6 days vs.2.0±0.8 days)and lower C-reactive protein activity(21.4[95%confidence interval(CI):11.9-36.7]mg/L vs.44.8[95%CI:26.9-63.1]mg/L)24 h after surgery.There were no significant differences in the time to defecation,serum concentrations of D-lactic acid,malondialdehyde,renal function,and frequency of severe postoperative complications as well as the LOS between the groups.Conclusion:Postoperative IVC respiratory variability-directed fluid therapy in AICU was facilitated in bowel movement but elicited a negligible beneficial effect on the short-term prognosis of patients undergoing LLR.Trial Registration:ChiCTR-INR-17013093.