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Model-independent determination on H_0 using the latest cosmic chronometer data

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Science China(physics,Mechanics & Astronomy) 2017年第11期60卷 1-10页

作者： Deng Wang Xin He Meng Theoretical physics Division Chern Institute of Mathematics Nankai University Department of physics Nankai University

We perform the updated constraints on the Hubble constant H_0 by using the model-independent method, Gaussian *** the latest 30 cosmic chronometer measurements, we obtain H_0= 67.38 ± 4.72 km s^(-1)Mpc^(-1), which is consistent with the Planck 2015 and Riess et al. analysis at 1σ confidence level. Different from the results of Busti et al. by only using 19 H(z) measurements, our reconstruction results of H(z) and the derived values of H_0 are insensitive to the concrete choice of covariance functions of Matern family.

关键词： Hubble constant cosmic chronometers model-independent method

Broadband continuum generation in an irregularly multicore microstructured optical fiber

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Chinese Optics Letters 2005年第6期3卷 355-357页

作者：闫培光贾亚青苏红新李乙钢丁镭张炜吕可诚张铁群朱晓农郭庆林周桂耀侯蓝田 insititute of physics nankai university Tianjin 300071 Institute of Modern Optics nankai university Key Laboratory of Optoelectronic Information Science and TechnologyEMCTianjin 300071 Insitute of physics Hebei university Baoding 071002 Institute of physics nankai university Tianjin 300071 Infrared Optical Fibers and Sensors Institute Yanshan university Qinhuangdao 066004

A broadband continuum generation is reported in a novel multicore microstructured optical fiber (MOF) where irregular air holes are randomly distributed in cladding. By launching ultrashort light pulses from a Ti:sapphire laser into a 190-mm-long fiber of this type, we have observed a group of continua generated from different cores, each with distinct color. 20-dB bandwidth of the broadest continuum is 1260 nm with an average power of 143 mW. The result confirms that the multicore MOF can be fabricated, with different dispersion profiles tailored for specific supercontinuum (SC) generation towards practical applications.

关键词： Electromagnetic dispersion Nonlinear optics Sapphire Solid state lasers

Phases of Dense Matter in Supernovae and Neutron Stars

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Plasma Science and Technology 2012年第7期14卷 581-584页

作者：申虹王延楠 School of physics Nankai University

We study the properties of dense matter at finite temperature with various proton fractions for use in supernova simulations. The relativistic mean-field theory is used to describe homogeneous nuclear matter, while the Thomas-Fermi approximation is adopted to describe inhomogeneous matter. We also discuss the equation of state of neutron star matter at zero temperature in a wide density range. The equation of state at high densities can be significantly softened by the inclusion of hyperons.

关键词： relativistic mean-field theory equation of state supernova neutron star

Interaction potential and thermo-correction to the equation of state for thermally stable Schwarzschild anti-de Sitter black holes

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Science China(physics,Mechanics & Astronomy) 2019年第1期62卷 27-31页

作者： Yan-Gang Miao Zhen-Ming Xu School of physics Nankai University

The microscopic structure of black holes remains a challenging subject. In this paper, based on the well-accepted fact that black holes can be mapped to thermodynamic systems, we make a preliminary exploration of the microscopic structure of the thermodynamically stable Schwarzschild anti-de-Sitter(SAdS) black hole. In accordance with the number density and thermodynamic scalar curvature, we give the interaction potential among the molecules of thermodynamically stable SAdS black holes and analyze its effectiveness. Moreover, we derive the thermo-correction to the equation of state for such black holes that arises from interactions among black-hole molecules using virial coefficients.

关键词： molecular potential number density equation of state

Multi-channel surface acoustic wave device and its application on all-fiber acousto-optic modulation

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Chinese Optics Letters 2010年第1期8卷 107-110页

作者：赵路明赵启大 Institute of physics Nankai University Institute of Modern Optics Nankai University

The interaction of multi-channel surface acoustic waves （SAWs） and a guided optical wave in fiber is studied, and the corresponding coupled wave equations are derived. A novel two-channel SAW all-fiber acousto-optic... 详细信息

关键词： Acoustic waves Acoustics Acoustoelectric effects Wave equations

Dark Energy Phenomenon from Backreaction Effect

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Communications in Theoretical physics 2019年第9期71卷 1109-1114页

作者： Yan-Hong Yao Xin-He Meng Department of physics Nankai University

In this paper, we interpret the dark energy phenomenon as an averaged effect caused by small scale inhomogeneities of the universe with the use of the spatial averaged approach of Buchert. Two models are considered here,one of which assumes that the backreaction term QD and the averaged spatial Ricci scalar (R)D obey the scaling laws of the volume scale factor a D at adequately late times, and the other one adopts the ansatz that the backreaction term QD is a constant in the recent universe. Thanks to the effective geometry introduced by Larena et al. in their previous work,we confront these two backreaction models with latest type Ia supernova and Hubble parameter observations, coming out with the results that the constant backreaction model is slightly favoured over the other model and the best fitting backreaction term in the scaling backreaction model behaves almost like a constant. Also, the numerical results show that the constant backreaction model predicts a smaller expansion rate and decelerated expansion rate than the other model does at redshifts higher than about 1, and both backreaction terms begin to accelerate the universe at a redshift around 0.5.

关键词： cosmological model dark energy cosmological backreaction effect

Investigation of P T-symmetric Hamiltonian Systems from an Alternative Point of View

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Communications in Theoretical physics 2012年第10期58卷 497-503页

作者：李军青李倩缪炎刚 School of physics Nankai University

Two non-Hermitian PT-symmetric Hamiltonian systems are reconsidered by means of the algebraic method which was originally proposed for the pseudo-Hermitian Hamiltonian systems rather than for the PT-symmetric *** with the way converting a non-Hermitian Hamiltonian to its Hermitian counterpart,this method has the merit that keeps the Hilbert space of the non-Hermitian PT-symmetric Hamiltonian *** order to give the positive definite inner product for the PT-symmetric systems,a new operator V,instead of C,can be *** operator V has the similar function to the operator C adopted normally in the PT-symmetric quantum mechanics,however,it can be constructed,as an advantage,directly in terms of *** spectra of the two non-Hermitian PT-symmetric systems are obtained,which coincide with that given in literature,and in particular,the Hilbert spaces associated with positive definite inner products are worked out.

关键词： PT symmetry positive definite inner product algebraic method

Determining Nuclear Form factor for Detection of Dark Matter in Relativistic Mean Field Theory

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Communications in Theoretical physics 2011年第6期55卷 1059-1064页

作者：陈亚正罗延安李磊中虹李学潜 School of physics Nankai University

In this work, we derive the nuclear form factor for the spin-independent collision between the WIMPs and nucleus in terms of the relativistic mean field （RMF） theory. Comparison with the traditional form factors which are commonly used in literature is given and it is found that our results are slightly above that of the 2PF model by 4% to 8%, but deviate from the Helm form factor by 15% to 25% for the whole recoil energy spectrum of 0 -100 keV. Moreover, taking Xe and Ge as examples, we show the dependence of the form Factor on the recoil energy.

关键词： dark matter form factor relativistic mean field

Tunneling Through Black Rings

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Communications in Theoretical physics 2007年第5期47卷 835-842页

作者： ZHAO Liu Department of physics,nankai university,Tianjin 300071,China Department of physics Nankai University

Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzedby use of the Parikh-Wilczek tunneling *** get the correct tunneling amplitude and emission rate,we adoptand develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronicdischarge all at once,and the effect of back reaction is also taken into *** constitutes a unified approach tothe tunneling *** the first law of thermodynamics for black rings holds,the emission rate is proportionalto the exponential of the change of Bekenstein-Hawking *** calculation for black ring temperatures agreesexactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

关键词： black ring radiation tunneling method