An Experimental Proposal to Test Dynamic Quantum Non-locality with Single-Atom Interferometry

Quantum non-locality based on the well-known Bell inequality is of kinematic nature. A different type of quantum non-locality, the non-locality of the quantum equation of motion, is recently put forward with connection to the Aharonov-Bohm effect [Nature Phys. 6, 151 (2010)]. Evolution of the displacement operator provides an example to manifest such dynamic quantum non-locality. We propose an experiment using single-atom interferometry to test such dynamic quantum non-locality. We show how to measure evolution of the displacement operator with clod atoms in a spin-dependent optical lattice potential and discuss signature to identify dynamic quantum non-locality under a realistic experimental setting.Comment: 4 page

Nonclassical photon pairs generated from a room-temperature atomic ensemble

We report experimental generation of non-classically correlated photon pairs from collective emission in a room-temperature atomic vapor cell. The nonclassical feature of the emission is demonstrated by observing a violation of the Cauchy-Schwarz inequality. Each pair of correlated photons are separated by a controllable time delay up to 2 microseconds. This experiment demonstrates an important step towards the realization of the Duan-Lukin-Cirac-Zoller scheme for scalable long-distance quantum communication.Comment: 4 pages, 2 figure

Reward-weighted DHER Mechanism For Multi-goal Reinforcement Learning With Application To Robotic Manipulation Control

In multi-goal reinforcement learning, an agent learns to achieve multiple goals using a goal-oriented policy, obtaining rewards from positions that have been achieved. Dynamic hindsight experience replay method improves the learning efficiency of the algorithm by matching the trajectories of past failed episodes and creating successful experiences. But these experiences are sampled and replayed by a random strategy, without considering the importance of the episode samples for learning. Therefore, not only bias is introduced as the training process, but also suboptimal improvements in terms of sample efficiency are obtained. To address these issues, this paper introduces a reward-weighted mechanism based on the dynamic hindsight experience replay (RDHER). We extend dynamic hindsight experience replay with a trade-off to make rewards calculated for hindsight experience numerically greater than actual rewards. Specifically, the hindsight rewards are multiplied by a weighting factor to increase the Q-value of the hindsight state–action pair, which drives the update of the policy to select the maximum action for the given hindsight transitions. Our experiments show that the hindsight bias can be reduced in training using the proposed method. Further, we demonstrate RDHER is effective in challenging robot manipulation tasks, and outperforms several other multi-goal baseline methods in terms of success rate

Natural plant polyphenols for alleviating oxidative damage in man: Current status and future perspectives

The balance between oxidation and reduction is important for maintaining a healthy biological system. Oxidative stress results from an imbalance between excessive formation of reactive oxygen species (ROS) and/or reactive nitrogen species (RNS) and limited endogenous defense systems, and this imbalance can adversely alter lipids, proteins and DNA, causing a number of human diseases. Thus, exogenous antioxidants that can neutralize the effect of free radicals are needed to diminish the cumulative effects of oxidative damage over human life span. Current research reveals that phenolic compounds in plants possess high antioxidant activity and free radical scavenging capacity and can prevent the body from oxidative damage over human life span. This review focuses on the present understanding of free radicals and antioxidants and their importance in human health and disease. Information about the chemical features of free radicals as well as their deleterious effects on cell structures is reviewed. The chemical structure and anti-oxidative mechanisms of essential polyphenols and their potential health benefits are presented. In addition, the limitation of natural antioxidants and a perspective on likely future trends in this field are also discussed.Keywords: Free radicals, Oxidative stress, Natural antioxidants, Polyphenols, Health benefits, Reactive oxygen species, Reactive nitrogen specie

The Origin of the Prompt Emission for Short GRB 170817A: Photosphere Emission or Synchrotron Emission?

The first gravitational-wave event from the merger of a binary neutron star system (GW170817) was detected recently. The associated short gamma-ray burst (GRB 170817A) has a low isotropic luminosity (~1047 erg s−1) and a peak energy E p ~ 145 keV during the initial main emission between −0.3 and 0.4 s. The origin of this short GRB is still under debate, but a plausible interpretation is that it is due to the off-axis emission from a structured jet. We consider two possibilities. First, since the best-fit spectral model for the main pulse of GRB 170817A is a cutoff power law with a hard low-energy photon index ($\alpha =-{0.62}_{-0.54}^{+0.49}$), we consider an off-axis photosphere model. We develop a theory of photosphere emission in a structured jet and find that such a model can reproduce a low-energy photon index that is softer than a blackbody through enhancing high-latitude emission. The model can naturally account for the observed spectrum. The best-fit Lorentz factor along the line of sight is ~20, which demands that there is a significant delay between the merger and jet launching. Alternatively, we consider that the emission is produced via synchrotron radiation in an optically thin region in an expanding jet with decreasing magnetic fields. This model does not require a delay of jet launching but demands a larger bulk Lorentz factor along the line of sight. We perform Markov Chain Monte Carlo fitting to the data within the framework of both models and obtain good fitting results in both cases