Electromagnetically induced transparency of interacting Rydberg atoms with two-body dephasing

We study electromagnetically induced transparency in a three-level ladder type configuration in ultracold atomic gases, where the upper level is an electronically highly excited Rydberg state. An effective distance dependent two-body dephasing can be induced in a regime where dipole-dipoles interaction couple nearly degenerate Rydberg pair states. We show that strong two-body dephasing can enhance the excitation blockade of neighboring Rydberg atoms. Due to the dissipative blockade, transmission of the probe light is reduced drastically by the two-body dephasing in the transparent window. The reduction of transmission is accompanied by a strong photon-photon anti-bunching. Around the Autler-Townes doublets, the photon bunching is amplified by the two-body dephasing, while transmission is largely unaffected. Besides relevant to the ongoing Rydberg atom studies, our study moreover provides a setting to explore and understand two-body dephasing dynamics in many-body systems

Accessing and Manipulating Dispersive Shock Waves in a Nonlinear and Nonlocal Rydberg Medium

Dispersive shock waves (DSWs) are fascinating wave phenomena occurring in media when nonlinearity overwhelms dispersion (or diffraction). Creating DSWs with low generation power and realizing their active controls is desirable but remains a longstanding challenge. Here, we propose a scheme to generate weak-light DSWs and realize their manipulations in an atomic gas involving strongly interacting Rydberg states under the condition of electromagnetically induced transparency (EIT). We show that for a two-dimensional (2D) Rydberg gas a weak nonlocality of optical Kerr nonlinearity can significantly change the edge speed of DSWs and induces a singular behavior of the edge speed and hence an instability of the DSWs. However, by increasing the degree of the Kerr nonlocality, the singular behavior of the edge speed and the instability of the DSWs can be suppressed. We also show that in a 3D Rydberg gas, DSWs can be created and propagate stably when the system works in the intermediate nonlocality regime. Due to the EIT effect and the giant nonlocal Kerr nonlinearity contributed by the Rydberg-Rydberg interaction, DSWs found here have extremely low generation power. In addition, an active control of DSWs can be realized; in particular, they can be stored and retrieved with high efficiency and fidelity through switching off and on a control laser field. The results reported here are useful not only for unveiling intriguing physics of DSWs but also for finding promising applications of nonlinear and nonlocal Rydberg media.Comment: 20 pages, 13 figure

Cyanidin-3-O-Glucoside Supplement Improves Sperm Quality and Spermatogenesis in a Mice Model of Ulcerative Colitis

Impaired fertility and low sperm quality are the global health problem with high attention. It has been noted that inflammation may impact fertility by affecting testicular spermatogenesis. Cyanidin-3-O-glucoside is a natural functional pigment with various health benefits. Nevertheless, studies on the mechanism by which C3G protects male reproduction in mice with ulcerative colitis remain scarce. The purpose of this study is to illustrate the potential mechanism of C3G for improving impaired fertility caused by colitis. A DSS-induced colitis model was applied to assess the effects of sperm quality with colitis and the health benefit role of C3G. Results indicated that C3G-treated mice exhibited higher body weight, longer colon length, less crypt damage and focal inflammation infiltration. Being consistent with that, low sperm count, low testis weight, high inflammation levels and abnormal thickness of seminiferous epithelium also observed in the DSS group were significantly recovered upon C3G treatment. These findings suggested that colitis has a close link to impaired fertility. Further analysis found that C3G could significantly suppress the inflammatory mediators in serum. Results conjointly indicated that C3G might improve the impaired fertility of mice with colitis by inhibiting inflammatory cytokines through the blood–testis barrier. C3G could be a promising daily supplement for ameliorating impaired fertility caused by colitis

Dephasing of ultracold cesium 80D5/280D_{5/2}-Rydberg Electromagnetically Induced Transparency

We study Rydberg electromagnetically induced transparency (EIT) of a cascade three-level atom involving 80$D_{5/2}$ state in a strong interaction regime employing a cesium ultracold cloud. In our experiment, a strong coupling laser couples 6$P_{3/2}$ to 80$D_{5/2}$ transition, while a weak probe, driving 6$S_{1/2}$ to 6$P_{3/2}$ transition, probes the coupling induced EIT signal. At the two-photon resonance, we observe that the EIT transmission decreases slowly with time, which is a signature of interaction induced metastability. The dephasing rate $\gamma_{\rm OD}$ is extracted with optical depth OD = $\gamma_{\rm OD}t$. We find that the optical depth linearly increases with time at onset for a fixed probe incident photon number $R_{\rm in}$ before saturation. The dephasing rate shows a nonlinear dependence on $R_{\rm in}$. The dephasing mechanism is mainly attributed to the strong dipole-dipole interactions, which leads to state transfer from $nD_{5/2}$ to other Rydberg states. We demonstrate that the typical transfer time $\tau_{0(80D)}$ obtained by the state selective field ionization technique is comparable with the decay time of EIT transmission $\tau_{0({\rm EIT})}$. The presented experiment provides a useful tool for investigating the strong nonlinear optical effects and metastable state in Rydberg many-body systems.Comment: 7 pages, 5 figure

Stable single light bullets and vortices and their active control in cold Rydberg gases

Realizing single light bullets and vortices that are stable in high dimensions is a long-standing goal in the study of nonlinear optical physics. On the other hand, the storage and retrieval of such stable high dimensional optical pulses may offer a variety of applications. Here we present a scheme to generate such optical pulses in a cold Rydberg atomic gas. By virtue of electromagnetically induced transparency, strong, long-range atom-atom interaction in Rydberg states is mapped to light fields, resulting in a giant, fast-responding nonlocal Kerr nonlinearity and the formation of light bullets and vortices carrying orbital angular momenta, which have extremely low generation power, very slow propagation velocity, and can stably propagate, with the stability provided by the combination of local and the nonlocal Kerr nonlinearities. We demonstrate that the light bullets and vortices obtained can be stored and retrieved in the system with high efficiency and fidelity. Our study provides a new route for manipulating high-dimensional nonlinear optical processes via the controlled optical nonlinearities in cold Rydberg gases

Facilitation-Induced Transparency and Single-Photon Switch with Dual-Channel Rydberg Interactions

We investigate facilitation-induced transparency (FIT) enabled by strong and long-range Rydberg atom interactions between two spatially separated optical channels. In this setting, the resonant two-photon excitation of Rydberg states in a target channel is conditioned by a single Rydberg excitation in a control channel. Through the contactless coupling enabled by the Rydberg interaction, the optical transparency of the target channel can be actively manipulated by steering the optical detuning in the control channel. By adopting a dressed-state picture, we identify two different interference pathways, in which one corresponds to Rydberg blockade and an emergent one results from facilitation. We show that the FIT is originated from the Rydberg interaction and the quantum interference effect between the two pathways, which is different from conventional electromagnetically induced transparency realized by single-body laser-atom coupling. We find that the FIT in such a dual-channel setting is rather robust, insensitive to changes of systemic parameters, and can be generalized to multichannel settings. Moreover, we demonstrate that such a FIT permits the realization of controllable single-photon switches, which also paves a route to detect Rydberg facilitation by using optical absorption spectra. Our study contributes to current efforts in probing correlated many-body dynamics and developing single-photon quantum devices based on Rydberg atom ensembles

Superradiance-induced multistability in one-dimensional driven Rydberg lattice gases

We study steady-state phases of a one-dimensional array of Rydberg atoms coupled by a microwave (MW) field where the higher-energy Rydberg state decays to the lower-energy one via single-body and collective (superradiant) decay. Using mean-field approaches, we examine the interplay among the MW coupling, intrastate van der Waals (vdW) interaction, and single-body and collective dissipation between Rydberg states. A linear stability analysis reveals that a series of phases, including uniform, antiferromagnetic, oscillatory, and bistable and multistable phases can be obtained. Without the vdW interaction, only uniform phases are found. In the presence of the vdW interaction, multistable solutions are enhanced when increasing the strength of the superradiant decay rate. Our numerical simulations show that the bistable and multistable phases are stabilized by superradiance in a long chain. The critical point between the uniform and multistable phases and its scaling with the atom number is obtained. Through numerically solving the master equation of a finite chain, we show that the mean-field multistable phase could be characterized by expectation values of Rydberg populations and two-body correlations between Rydberg atoms in different sites

Progress in Preparation and Application of Anthocyanin-Starch Complexes: A Review

Anthocyanins are natural colorants that have attracted increasing attention due to their wide color range, non-toxicity and health benefits. Although anthocyanins have great application potential in the food and pharmaceutical industries, their application is limited due to the relative instability. Starch is considered as a good protective agent for anthocyanins, which can improve the stability of anthocyanins during storage. In recent years, many studies have combined the two compounds by different methods such as physical and chemical methods. This can not only enhance the stability of anthocyanins, but also improve the mechanical properties of starch, which will result in better application of starch and anthocyanins in drug delivery, biomedicine, agriculture, and food production. The basic structural characteristics of anthocyanins and starch, and the various methods for preparing anthocyanin-starch complexes are summarized herein. Also, the effects of anthocyanin-starch interactions on anthocyanin stability, bioavailability and antioxidant activity and on starch crystallinity, gelatinization properties, mechanical properties and digestibility are reviewed, and the current progress in the application of anthocyanin-starch complexes is outlined. It is hoped that this review will provide a reference for future research on the preparation and application of anthocyanin-starch complexes

Observation of Blackbody Radiation Enhanced Superradiance in Ultracold Rydberg Gases

An ensemble of excited atoms can synchronize emission of light collectively in a process known as superradiance when its characteristic size is smaller than the wavelength of emitted photons. The underlying superradiance depends strongly on electromagnetic (photon) fields surrounding the atomic ensemble. High mode densities of microwave photons from 300 K blackbody radiation (BBR) significantly enhance decay rates of Rydberg states to neighbouring states, enabling superradiance that is not possible with bare vacuum induced spontaneous decay. Here we report observations of the superradiance of ultracold Rydberg atoms embedded in a bath of room-temperature photons. The temporal evolution of the Rydberg |nD to |(n + 1)P superradiant decay of Cs atoms (n the principal quantum number) is measured directly in free space. Theoretical simulations confirm the BBR enhanced superradiance in large Rydberg ensembles. We demonstrate that the van der Waals interactions between Rydberg atoms change the superradiant dynamics and modify the scaling of the superradiance. In the presence of static electric fields, we find that the superradiance becomes slow, potentially due to many-body interaction induced dephasing. Our study provides insights into many-body dynamics of interacting atoms coupled to thermal BBR, and might open a route to the design of blackbody thermometry at microwave frequencies via collective, dissipative photon-atom interactions

Accessing and Manipulating Dispersive Shock Waves in a Nonlinear and Nonlocal Rydberg Medium

Dispersive shock waves (DSWs) are fascinating wave phenomena occurring in media when nonlinearity overwhelms dispersion (or diffraction). Creating DSWs with low generation power and realizing their active controls is desirable but remains a longstanding challenge. Here, we propose a scheme to generate weak-light DSWs and realize their manipulations in an atomic gas involving strongly interacting Rydberg states under the condition of electromagnetically induced transparency (EIT). We show that for a two-dimensional (2D) Rydberg gas a weak nonlocality of optical Kerr nonlinearity can significantly change the edge speed of DSWs, and induces a singular behavior of the edge speed and hence an instability of the DSWs. However, by increasing the degree of the Kerr nonlocality, the singular behavior of the edge speed and the instability of the DSWs can be suppressed. We also show that in a 3D Rydberg gas, DSWs can be created and propagate stably when the system works in the intermediate nonlocality regime. Due to the EIT effect and the giant nonlocal Kerr nonlinearity contributed by the Rydberg-Rydberg interaction, DSWs found here have extremely low generation power. In addition, an active control of DSWs can be realized; in particular, they can be stored and retrieved with high efficiency and fidelity through switching off and on a control laser field. The results reported here are useful not only for unveiling intriguing physics of DSWs but also for finding promising applications of nonlinear and nonlocal Rydberg media