Loading...

Table of Content

    20 September 2018 Volume 37 Issue 9
      
    Converting mixed states into physically equivalent pure state by the IWOP method
    ZHAN De-hui1,LU Dao-ming1,FAN Hong-yi2
    College Physics. 2018, 37(9):  1-3.  doi:10.16854 /j.cnki.1000-0712.170730
    Abstract ( 1181 )   PDF (514KB) ( 310 )  
    Related Articles | Metrics
    We propose the IWOP method to convert mixed states into physically equivalent pure state,this not only brings some new explanation for the states,but also simplify the ensemble average calculation.
    Bohr model of hydrogen atom,correspondence principle and matrix mechanics
    HUANG Yong-yi,ZHANG Chun-min
    College Physics. 2018, 37(9):  4-8.  doi:10.16854 /j.cnki.1000-0712.180045
    Abstract ( 2081 )   PDF (803KB) ( 749 )  
    Related Articles | Metrics
    This paper reproduces the original Bohr model of hydrogen atom,from which we extract Bohr’s correspondence principle. We apply the correspondence principle to the two examples: the calculations of atomic spectra intensities from classical physics and the creations of matrix mechanics.
    The effect of second general relativistic on orbit of mercury: modification to radial motion
    LIU Tian-gui,LI Qian,WANG Xin,LIU Quan-hui
    College Physics. 2018, 37(9):  9-10.  doi:10.16854 /j.cnki.1000-0712.170666
    Abstract ( 2193 )   PDF (836KB) ( 688 )  
    Related Articles | Metrics
    One of the three classic tests of general relativity is the perihelion precession of mercury,which is resulted from the angular motion modification. In fact,there is modification to the radial motion which leads to the contraction of the orbit,and this modification is up to order of 10 km which can be measurable duo to advances of distance measurement technology.
    An application example of the dimension method and Π-theorem
    ZHOU Guo-quan,QI Ning,PAN Wei-shen
    College Physics. 2018, 37(9):  11-14.  doi:10.16854 /j.cnki.1000-0712.170698
    Abstract ( 1400 )   PDF (891KB) ( 515 )  
    Related Articles | Metrics
    The dimension method and Π- theorem have been associated with experimental measurement to study the period revision for the transient process of a RLC electromagnetic vibration with a low damping degree.The first-order revision coefficient has been measured concretely and calculated accurately; and the second-order revision coefficient has been derived accurately and evaluated. The result is very well coincident with the approximate expansion of the strict vibration-period formula for the RLC transient process with a low damping degree.
    Notes on an expression of Laplace operator in the orthogonal coordinate
    LIU Chun-ping
    College Physics. 2018, 37(9):  15-16.  doi:10.16854 /j.cnki.1000-0712.180098
    Abstract ( 1573 )   PDF (739KB) ( 460 )  
    Related Articles | Metrics
    Further study on the expression of Laplace operator stated in former literatures has been done. The calculation process has been simplified by using knowledge of inverse function and vector algebra.
    Application of time-dependent Schrdinger equation to the design of quantum search algorithm
    PENG Yong-gang
    College Physics. 2018, 37(9):  17-24.  doi:10.16854 /j.cnki.1000-0712.180072
    Abstract ( 1451 )   PDF (1076KB) ( 495 )  
    Related Articles | Metrics
    Based on the two-qubit quantum computer physical model,the rule of designing quantum search algorithm nuclear magnetic resonance pulse sequence parameters is proposed through the approximate solution of the two-body the time-dependent Schrdinger equation in a rotating frame. Specified parameters are given. According to the Suzuki symmetric product-formula,the time-step evolution operator is decomposed into ordered product of some symmetric exponential operators. By using this method,the time-dependent Schrdinger equation is numerically calculated. The numerical calculation results verify that parameters and rules of designing parameter are correct.
    A study on multiple self synchronization of metronomes
    LU Jun-ling,GU Chen,QIN Lian-hua,REN Nai-jing
    College Physics. 2018, 37(9):  25-29.  doi:10.16854 /j.cnki.1000-0712.170682
    Abstract ( 2729 )   PDF (1223KB) ( 561 )  
    Related Articles | Metrics
    We analyze the synchronous self-locking of metronomes and gave its physical explanation. The pendulum is in vibration damping after captured by escapement of metronome and in the meantime,all metronomes are weakly coupled by the vibration,resulting in the vibration phase shift backward than the former one and shift forward than the latter one. Finally,all the vibration of metronome is synchronous.
    A virtual simulation experiment design of standing wave tube based on ANSYS software
    SUN Yang1,HUA Bo2
    College Physics. 2018, 37(9):  30-36.  doi:10.16854 /j.cnki.1000-0712.170643
    Abstract ( 1866 )   PDF (1600KB) ( 401 )  
    Related Articles | Metrics
    In recent years,virtual simulation experiment teaching has received more and more attention of colleges and universities both at home and abroad because of its low cost,high degree of safety and strong flexibility. A virtual simulation experiment of standing wave tube is designed based on a finite element analysis software ANSYS.Three experimental methods are involved,including standing wave ratio method,transfer function method and pipe pulse method. The contrastive analysis results of error and calculation efficiency are given. Two operating modes, graphical user interface ( GUI) and command flow are provided. This design can make up for the deficiency of acoustic experiments in physics experiments of college and has reference value for the construction of college physics virtual simulation experiment.
    Application of Fabry-Perot interference to ultrashort laser pulse measurement
    LIU Wen-jun,SUN Zheng-he,REN Shou-tian,GAO Ren-xi,PAN Yu-zhai,MIAO Jie-guang
    College Physics. 2018, 37(9):  37-40.  doi:10.16854 /j.cnki.1000-0712.170723
    Abstract ( 1280 )   PDF (1095KB) ( 348 )  
    Related Articles | Metrics
    Fabry-Perot interferometer is applied to measure ultrashort laser pulse. The principle of ultrashort laser pulse measurement based on Fabry-Perot interferometer is analyzed. Experiments on ultrashort pulse measurement are conducted. The experimental results are in agreement with those obtained by using Michelson interference autocorrelation.
    James Hopwood Jeans———A perfect combination of academic research and teaching research
    YANG Qing-yu1,PENG Chang-de2
    College Physics. 2018, 37(9):  41-45.  doi:10.16854 /j.cnki.1000-0712.170709
    Abstract ( 1763 )   PDF (1039KB) ( 327 )  
    Related Articles | Metrics
    James Hopewood Jeans is an outstanding example in history of physics for perfecting combination of academic research and teaching research. He has been fruitful in many disciplines of physics. In order to improve the teaching level of the subject of theory physics,he has carefully compiled and published many classic textbooks.This paper shows his research style and the characteristics of academic transformation through the history of physics,and hopes to bring useful enlightenment to the physical people.
    Research on the application of extrapolation in physics experiment
    HUANG Xin-tong,NI Min
    College Physics. 2018, 37(9):  46-50.  doi:10.16854 /j.cnki.1000-0712.170517
    Abstract ( 1752 )   PDF (1255KB) ( 539 )  
    Related Articles | Metrics
    From the concept of extrapolation,the extrapolation method is used to measure the physical quantity difficult to measure in physical experiment,reduce the error of experimental system,and simplify the application of experimental method for reference.
    Propagation characteristics of plane electromagnetic waves in dielectric anisotropic periodic media
    LUO Jun,TANG Zheng-hua,DUAN Sheng
    College Physics. 2018, 37(9):  51-55.  doi:10.16854 /j.cnki.1000-0712.180036
    Abstract ( 1373 )   PDF (1073KB) ( 508 )  
    Related Articles | Metrics
    In this paper,the transmission matrix problem of a plane electromagnetic wave in one-dimensional dielectric isotropic periodic medium is extended to one -dimensional dielectric anisotropic periodic medium. The transmission matrix of a plane electromagnetic wave in such medium is obtained. The derivation of the matrix is mainly based on the Maxwell equations and continuity conditions of the electromagnetic wave at the interface of the medium. Namely,the tangential components of the electric field and magnetic field of the electromagnetic wave are continuous at the interface of the medium. The derivation of this matrix can deepen the students' understanding the course“Electromagnetic Field and Electromagnetic Wave”. This matrix is also the basis for obtaining the field distribution, the dispersion relation and surface mode properties of the electromagnetic wave in a one-dimensional dielectric anisotropic periodic medium. Therefore,this transmission matrix is of great significance for both scientific research and teaching.
    Exploration of the innovative thinking in solving mathematical physics equations
    WANG Chang,WANG Qiao-chu,LIU Wei,SHI Qing-fan
    College Physics. 2018, 37(9):  56-59.  doi:10.16854 /j.cnki.1000-0712.170562
    Abstract ( 1237 )   PDF (1054KB) ( 607 )  
    Related Articles | Metrics
    The mathematical physics equation is used to describe the states of various physical fields in the continuous distributed space and physical processes. Because mathematical physics equations are the partial differential equations which contain multiple variables. They are different to solve,then many innovative ideas are emerged in the history of the solution. This paper discusses the ways of thinking when methods such as separation of variables,infinite series and Sturm-Liouville theory were established based on the historical facts. Learning about the formation process of these innovative ideas can enlighten the study of mathematical physics equations.
    Investigation on quantum coherence in a two-qubit Heisenberg XXZ model
    LI Bo-xin1,LI Shan-hong1,QIN Meng2,WANG Li2
    College Physics. 2018, 37(9):  60-65.  doi:10.16854 /j.cnki.1000-0712.170593
    Abstract ( 1238 )   PDF (1994KB) ( 325 )  
    Related Articles | Metrics
    The quantum coherence in a two-qubit Heisenberg XXZ model is investigated under an inhomogeneous magnetic field and homogeneous magnetic field. The influence of different parameters on quantum coherence is discussed in detail. We find that the dependence of quantum coherence on inhomogeneous magnetic field will smooth if the uniform magnetic field gets involved. Under different anisotropy parameters and magnetic field,quantum coherence versus temperature has many considerable differences. We find that the quantum coherence are unimodal about inhomogeneous magnetic field by comparing with entanglement. In addition,we also study the dynamical behavior of quantum coherence with different initial states. We show the influence of inhomogeneous magnetic field on the evolution. The results of this paper will provide some help to understand quantum coherence.