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80 - Y. Zhou , S. Luo , J. Liu 2021
In this paper, we study two-photon interference of broadband chaotic light in a Michelson interferometer with two-photon-absorption detector. The theoretical analysis is based on two-photon interference and Feynman path integral theory. The two-photo n coherence matrix is introduced to calculate the second-order interference pattern with polarizations being taken into account. Our study shows that the polarization is another dimension, as well as time and space, to tune the interference pattern in the two-photon interference process. It can act as a switch to manipulate the interference process and open the gate to many new experimental schemes.
149 - Y. Zhou , C. Cocuzza , F. Delcarro 2021
We present a comprehensive impact study of future Electron-Ion Collider (EIC) data for parity-conserving and parity-violating polarization asymmetries on quark and gluon helicity distributions in the proton. The study, which is based on the JAM Monte Carlo global QCD analysis framework, explores the role of the extrapolation uncertainty and SU(3) flavor symmetry constraints in the simulated double-spin asymmetry, $A_{LL}$, at small parton momentum fractions $x$ and its effect on the extracted parton polarizations. We find that different assumptions about $A_{LL}$ extrapolations and SU(3) symmetry can have significant consequences for the integrated quark and gluon polarizations, for polarized proton, deuteron and $^3$He beams. For the parity-violating asymmetry, $A_{UL}$, we study the potential impact on the polarized strange quark distribution with different extrapolations of $A_{UL}$, finding the constraining power to be ultimately limited by the EIC machine luminosity.
105 - Y. Shemerliuk , Y. Zhou , Z. Yang 2021
We report an optimized chemical vapor transport method to grow single crystals of (Mn$_{1-x}$Ni$_x$)$_2$P$_2$S$_6$ where x = 0, 0.3, 0.5, 0.7 & 1. Single crystals up to 4,mm,$times$,3,mm,$times$,200,$mu$m were obtained by this method. As-grown crysta ls characterized by means of scanning electron microscopy, and powder x-ray diffraction measurements. The structural characterization shows that all crystals crystallize in monoclinic symmetry with the space group $C2/m$ (No. 12). We have further investigated the magnetic properties of this series of single crystals. The magnetic measurements of the all as-grown single crystals show long-range antiferromagnetic order along all crystallographic principal axes. Overall, the Neel temperature TN is non-monotonous, with increasing $Ni^{2+}$ doping the temperature of the antiferromagnetic phase transition first decreases from 80 K for pristine Mn$_2$P$_2$S$_6$ (x = 0) up to x = 0.5, and then increases again to 155 K for pure Ni$_2$P$_2$S$_6$ (x = 1). The magnetic anisotropy switches from out-of-plane to in-plane as a function of composition in (Mn$_{1-x}$Ni$_x$)$_2$P$_2$S$_6$ series. Transport studies under hydrostatic pressure on the parent compound Mn$_2$P$_2$S$_6$ evidence an insulator-metal transition at an applied critical pressure of ~22 GPa
316 - Q. Wang , Y. Zhou , J. Shen 2021
This article comes up with an intraday trading strategy under T+1 using Markowitz optimization and Multilayer Perceptron (MLP) with published stock data obtained from the Shenzhen Stock Exchange and Shanghai Stock Exchange. The empirical results reve al the profitability of Markowitz portfolio optimization and validate the intraday stock price prediction using MLP. The findings further combine the Markowitz optimization, an MLP with the trading strategy, to clarify this strategys feasibility.
79 - H. Xu , Y. Zhou , U. Bechstedt 2020
The proton--proton elastic differential cross section at very small four momentum transfer squared has been measured at three different incident proton momenta in the range of 2.5 to 3.2 GeV/c by detecting the recoil proton at polar angles close to $ 90^circ$. The measurement was performed at COSY with the KOALA detector covering the Coulomb-nuclear interference region. The total cross section $sigma_text{tot}$, which has been determined precisely, is consistent with previous measurements. The values of the slope parameter $B$ and the relative real amplitude ratio $rho$ determined in this experiment alleviate the lack of data in the relevant energy region. This precise data on $rho$ might be an important check for a new dispersion analysis.
For a thermodynamic system obeying both the equipartition theorem in high temperature and the third law in low temperature, the curve showing relationship between the specific heat and the temperature has two common behaviors: it terminates at zero w hen the temperature is zero Kelvin and converges to a constant as temperature is higher and higher. Since it is always possible to find the characteristic temperature $T_{C}$ to mark the excited temperature as the specific heat almost reaches the equipartition value, it is reasonable to find a temperature in low temperature interval, complementary to $T_{C}$. The present study reports a possibly universal existence of the such a temperature $vartheta$, defined by that at which the specific heat falls textit{fastest} along with decrease of the temperature. For the Debye model of solids, above the temperature $vartheta$ the Debyes law starts to fail.
The presented work investigates the possible formation of terrestrial planets in the habitable zone (HZ) of the exoplanetary system HD 141399. In this system the HZ is located approximately between the planets c (a = 0.7 au) and d (a = 2.1 au). Exten sive numerical integrations of the equations of motion in the pure Newtonian framework of small bodies with different initial conditions in the HZ are performed. Our investigations included several steps starting with 500 massless bodies distributed between planets c and d in order to model the development of the disk of small bodies. It turns out that after some 10^6 years a belt-like structure analogue to the main belt inside Jupiter in our Solar System appears. We then proceed with giving the small bodies masses (Moon-mass) and take into account the gravitational interaction between these planetesimal-like objects. The growing of the objects - with certain percentage of water - due to collisions is computed in order to look for the formation of terrestrial planets. We observe that planets form in regions connected to mean motion resonances (MMR). So far there is no observational evidence of terrestrial planets in the system of HD 141399 but from our results we can conclude that the formation of terrestrial planets - even with an appropriate amount of water necessary for being habitable - in the HZ would have been possible.
195 - Z.H. Peng , J.H. Ding , Y. Zhou 2017
We experimentally study a vacuum-induced Autler-Townes doublet in a superconducting three-level artificial atom strongly coupled to a coplanar waveguide resonator and simultaneously to a transmission line. The Autler-Townes splitting is observed in t he reflection spectrum from the three-level atom in a transition between the ground state and the second excited state when the transition between the two excited states is resonant with a resonator. By applying a driving field to the resonator, we observe a change in the regime of the Autler-Townes splitting from quantum (vacuum-induced) to classical (with many resonator photons). Furthermore, we show that the reflection of propagating microwaves in a transmission line could be controlled by different frequency single photons in a resonator.
123 - Y. Zhou , L. Miao , P. Wang 2016
Single monolayer FeSe film grown on Nb-doped SrTiO$_3$(001) substrate shows the highest superconducting transition temperature (T$_C$ $sim$ 100 K) among the iron-based superconductors (iron-pnictide), while T$_C$ of bulk FeSe is only $sim$ 8 K. Antif erromagnetic spin fluctuations were believed to be crucial in iron-pnictides, which has inspired several proposals to understand the FeSe/SrTiO$_3$ system. Although bulk FeSe does not show the antiferromagnetic order, calculations suggest that the parent FeSe/SrTiO$_3$ films are AFM. Experimentally, due to lacking of direct probe, the magnetic state of FeSe/SrTiO$_3$ films remains mysterious. Here, we report the direct evidences of the antiferromagnetic order in the parent FeSe/SrTiO$_3$ films by the magnetic exchange bias effect measurements. The phase transition temperature is $geq$ 140 K for single monolayer film. The AFM order disappears after electron doping.
89 - Y. Li , W. Yuan , H. Y. Zhou 2014
We report the finding of an unobscured type II Active Galactic Nuclei (AGN) candidate, SDSS J012032.19-005501.9 at a relatively high redshift of 0.601,which shows a number of unusual properties. It varies significantly on timescales of years as typic al type I AGNs and marginally on timescales of weeks. The color-magnitude relation and the structure function are also consistent with that of type I AGNs, which imply that its variability likely originates from the black hole accretion system .However, no broad emission line is detected in the SDSS spectrum, and the upper limit of the equivalent width of the H$rm beta$ broad emission line is much less than that of type I AGNs. These properties suggest that SDSS J012032.19-005501.9 may be an unobscured quasar without broad emission lines intrinsically, namely an unobscured type II AGN or true type II AGN. Furthermore, its continuum luminosity is at least one order of magnitude fainter than the average value of thepast century expected from the [OIII] emission line. It indicates that SDSS J012032.19-005501.9 may be switching off. Additional possible scenarios to explain this intriguing source are also discussed. Future deep observations at multi-wavelengths are needed to reveal the nature of this peculiar and intriguing AGN.
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