Observation of Fast Evolution in Parity-Time-Symmetric System

To find and realize the optimal evolution between two states is significant both in theory and application. In quantum mechanics, the minimal evolution is bounded by the gap between the largest and smallest eigenvalue of the Hamiltonian. In the parity-time-symmetric(PT-symmetric) Hamiltonian theory, it was predicted that the optimized evolution time can be reduced drastically comparing to the bound in the Hermitian case, and can become even zero. In this Letter, we report the experimental observation of the fast evolution of a PT-symmetric Hamiltonian in an nuclear magnetic resonance (NMR) quantum system. The experimental results demonstrate that the PT-symmetric Hamiltonian can indeed evolve much faster than that in a quantum system, and time it takes can be arbitrary close to zero.Comment: 13 pages, 5 figure

Energy-Momentum Tensor and Related Experimental Analysis of Electromagnetic Waves in Media

We find that the energy-momentum tensor of electromagnetic waves in media is very similar to that of ordinary fluids, and concepts such as density, pressure, and energy transfer rate can be similarly defined. On this basis, we conducted a detailed theoretical analysis on the mean momentum and equivalent mass of photons in the medium, the relationship between pressure and polarization of beams, the influence of polarization energy and magnetization energy of the medium, the Bernoulli effect of beams and the energy-momentum tensor of beams in moving media. We also obtain a conservation new energy-momentum tensor based on the interaction term between the electromagnetic field and the medium. From this energy-momentum tensor, we can derive both the Minkowski momentum and the Abraham momentum simultaneously. We find that Minkowski momentum is actually a canonical momentum that considers the influence of the interaction between electromagnetic waves and media, while Abraham momentum is actually a mechanical momentum that does not consider the influence of the interaction between electromagnetic waves and media. Based on the theory obtained in this paper, we have provided theoretical explanations for Jones'experiment of light pressure in a medium, Ashkin's free liquid surface deformation experiment, Weilong's optical fiber deformation experiment, and frequency shift measurement experiment. The theory obtained in this paper can self-consistently explain the above experiments simultaneously. Unlike the Minkowski and Abraham tensors, according to the energy-momentum tensor proposed in this paper, a beam in a medium also generates a pressure on its side, and the direction of this pressure is related to the polarization of the beam. The findings of this paper may shed new light on the application of light.Comment: Page 29, Figure

Graviton-Photon Conversion in Atoms and the Detection of Gravitons

We study graviton-photon conversion in ground-based experiments. From graviton to photon tran- sition, we calculate the cross section of graviton-atom interaction in the presence of spherical atomic electric fields; the obtained results hold for graviton energy around 100 keV - 1 GeV and would be enhanced by crystal structures, thus it gives a chance to catch MeV level gravitons from the universe with current neutrino facilities. From photon to graviton transition, we propose an experiment using entangled pho- ton pairs to count missing photons passing through transverse magnetic tunnel, which could be used to verify the energy quantization of gravitational field

The application of geochemical methods in earthquake prediction in China

Several geochemical anomalies were observed before the Haichen, Longling, Tangshan, and Songpan earthquakes and their strong aftershocks. They included changes in groundwater radon levels; chemical composition of the groundwater (concentration of Ca^(++), Mg^(++), Cl^−, SO_4= and HCO_3− ions); conductivity; and dissolved gases such as H_2, CO_2, etc. In addition, anomalous changes in water color and quality were observed before these large earthquakes. Before some events gases escaped from the surface, and there were reports of "ground odors" being smelled by local residents. The large amount of radon data can be grouped into long‐term and short‐term anomalies. The long‐term anomalies have a radon emission build up time of from a few months to more than a year. The short‐term anomalies have durations from a few hours or less to a few months

Preventive effect of Tribulus Terrestris extract on exercise-related immunosuppression and its mechanism

Introduction: To investigate preventive effect of Tribulus terrestris extract (TT) on exercise-related immunosuppression in rats and explore the mechanisms- the role of Glucocorticoid (GC), Glucocorticoid Receptor (GR) and NF-kB inhibitor protein alpha (IkBa). Methods: Thirty male SD rats were randomly divided into control group, over-trained group and over-trained plus TT group. The last two groups were trained on a motor-driven treadmill with a progressively increased load for 6 weeks. The over-trained plus TT rats took the medicine by gastric irrigation while the others ingested the same amount of saline. The numbers of CD3+, CD4+ and CD8+ T cells and natural killing (NK) and NKT cells were detected by Flow Cytometry. The plasma levels of testosterone and corticosterone and the protein levels of GR and IkBa in livers of rats were determined by ELISA and Western blot, respectively. Results: ①Distinct decreases of body weigh, testosterone/corticosterone (T/C) ratio, the numbers of CD3+T and NK cells were found in over-trained rats compared with that of control rats, indicating successful establishement of exercise-related immunosuppression. ②Supplement of TT lead to significant increases of T/C ratio, CD4+/CD8+ ratio and the amounts of CD8+ cells, NK and NKT cells in the over-trained rats. ③The plasma levels of GC in over-trained rats kept unchanged compared to control rats, while obvious decrease (about 50% of over-trained rats) was observed in over-trained plus TT rats. ④The protein levels of GR decreased in the livers of over-trained rats, while obvious increases of protein expression of GR were observed in over-trained plus TT rats. ⑤The protein levels of IkBa raised significantly in the livers of over-trained rats, while reduced protein levels of IkBa were shown in over-trained plus TT rats. Conclusions: These results indicated that: ①supplement of TT improved the suppressed immune function resulted from over-training in rats. ②TT decreased the plasma levels of GC and the protein levels of IkBa in livers of over-trained rats and increased the protein levels of GR in livers of over-trained rats, which might be related to the preventive effect of TT on exercise-related immunosuppression