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Electromagnetic retarded interaction and symmetry violation of time reversal in high order stimulated radiation and absorption processes of light

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Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 282-298页

作者： MEI XiaoChun department of physics,Fuzhou university,Fuzhou 350025,china department of physics Fuzhou University Fuzhou China

It has been proved that when the retarded effect (or multiple moment effect) of radiation fields is taken into account,the high order stimulated radiation and stimulated absorption probabilities of light are not the same so that time reversal symmetry would be violated,though the Hamiltonian of electromagnetic interaction is still unchanged under time reversal. The reason to cause time reversal symmetry violation is that certain filial or partial transition processes of bound atoms are forbidden or cannot be achieved due to the law of energy conservation and the special states of atoms themselves. These restrictions would cause the symmetry violation of time reversal of other filial or partial transition processes which can be actualized really. The symmetry violation is also relative to the asymmetry of initial states of bound atoms before and after time reversal. For the electromagnetic interaction between non-bound atoms and radiation field,there is no such kind of symmetry violation of time reversal. In this way,the current formula on the parameters of stimulated radiation and absorption of light with time reversal sym-metry should be revised. A more reliable foundation can be established for the theories of laser and nonlinear optics in which non-equilibrium processes are in-volved.

关键词： quantum mechanics stimulated radiation and absorption of light retarded interaction time reversal symmetry violation laser nonlinear optics non-equilibrium processes

Formation of bulk ferromagnetic nanostructured Fe_(40)Ni_(40)P_(14)B_6 alloys by metastable liquid spinodal decomposition

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Science china(Technological Sciences) 2009年第7期52卷 1919-1922页

作者： LI Qiang1,2 1 School of physics Science and Technology, Xinjiang university, Urumqi 830046, china 2.department of physics, The Chinese university of HongKong, Shatin N.T., HongKong, china School of physics Science and Technology Xinjiang University Urumqi China department of physics The Chinese University of HongKong Shatin N.T. HongKong China

Nanostructured Fe40Ni40P14B6 alloy ingots of 3―5 mm in diameter could be synthesized by a metastable liquid state spinodal decomposition method. For undercooling T> 260 K, the microstructure of the undercooled specimen had exhibited liquid state spinodal decomposition in the undercooled liquid state. The microstructure could be described as two intertwining networks with small grains dispersed in them. For undercooling T>290 K, the overall microstructure of the specimen changed into a granular morphology. The average grain sizes of the small and large grains are 30 nm and 80 nm, respectively. These prepared samples are soft magnets with saturation magnetization Bs 0.744 T.

关键词： nanomaterials magnetic materials solidification bulk nanostructured alloy Fe40Ni40P14B6 metastable liquid spinodal decomposition

Pairwise entanglement and local polarization of Heisenberg model

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Science china(physics,Mechanics & Astronomy) 2008年第10期51卷 1515-1522页

作者： XI XiaoQiang1,2, ZHANG Tao3, YUE RuiHong3,4 & LIU WuMing2 1 department of Applied Mathematics and physics, Xi’an Institute of Post and Telecommunications, Xi’an 710061, china 2 Beijing National Laboratory for Condensed Matter physics, Institute of physics, Chinese Academy of Sciences, Beijing 100080, china 3 Institute of Modern physics, Northwest university, Xi’an 710069, china 4 department of physics, Ningbo university, Ningbo 315211, china department of Applied Mathematics and physics Xi’an Institute of Post and Telecommunications Xi’an China Beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China Institute of Modern physics Northwest University Xi’an China department of physics Ningbo University Ningbo China

The characteristics of pairwise entanglement and local polarization (LP) are dis-cussed by studying the ground state (states) of the Heisenberg XX model. The re-sults show that: the ground state (states) is (are) composed of the micro states with the minimal polarization (0 for even qubit and 1/2 for odd qubit); LP and the prob-ability of the micro state have an intimate relation, i.e. the stronger the LP, the smaller the probability, and the same LP corresponds to the same probability; the pairwise entanglement of the ground state is the biggest in all eigenvectors. It is found that the pairwise entanglement is decreased by the state degeneracy and the system size. The concurrence approaches a fixed value of about 0.3412 (for odd-qubit chain) or 0.3491 (for even-qubit chain) if the qubit number is large enough.

关键词： Heisenberg XX model local polarization pairwise entanglement

Modified Wave Particle Duality and Black Hole physics

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Communications in Theoretical physics 2007年第7期48卷 93-98页

作者： LI Xiang department of physics,Nanchang university,Nanchang 330047,china department of physics Nanchang University Nanchang 330047 China

de Broglie relation is revisited,in consideration of a generalization of canonical commuting *** effects on particle's localization and black hole physics are also discussed,in a heuristic manner.

关键词： wave-particle duality dispersion relation localization limit black hole entropy

Light-induced unconventional Landau levels of ultracold fermions in a trilayer honeycomb lattice

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 321-326页

作者： HOU JingMin department of physics,Southeast university,Nanjing 211189,china department of physics Southeast University Nanjing China

The spectrum of cold fermionic atoms is studied in a trilayer honeycomb optical lattice subjected to a perpendicular effective magnetic field,which is created with optical means. In the low energy approximation,the spectrum shows unconventional Landau levels,which are proportional to the 3/2 power of integer numbers. The zoro modes exist and the quasiparticles are chiral. It is also proposed to identify the unconventional Landau levels via probing the dynamic structure factor of the system with Bragg spectroscopy.

关键词： cold atoms trilayer honeycomb lattice unconventional Landau levels

Microwave peak absorption frequency of liquid

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Science china(physics,Mechanics & Astronomy) 2008年第9期51卷 1254-1263页

作者： HAN GuangZe1 & CHEN MingDong2 1 department of physics,South china university of Technology,Guangzhou 510640,china 2 Guangzhou Auto College,South china university of Technology,Guangzhou 510800,china department of physics South China University of Technology Guangzhou China Guangzhou Auto College South China University of Technology Guangzhou China

Microwave-assisted extraction is a new effective method which has practical ap-plications in many fields. Microwave heating is one of its physical mechanisms,and it also has the characteristic of selectivity. When the applied microwave fre-quency equals a certain absorption frequency of the material (or specific compo-nent),the material will intensively absorb microwave energy. This is also known as resonant absorption,and the frequency is called the peak absorption frequency which depends on the physical structure of the material. In this work,dynamic hy-drogen bond energy was included in molecular activation energy; with the liquid cell model,the expression of interaction energy between dipolar molecules was derived. The rotational relaxation time was gotten from the Eyring viscosity formula. Then based on the relationship between dielectric dissipation coefficient and re-laxation time,the expression of microwave peak absorption frequency as a func-tion of the material physical structure,rotational inertia and electrical dipole mo-ment of molecules was established. These theoretical formulas were applied to water and benzene,and the calculated results agree fairly well with the experi-mental data. This work can not only deepen the study of the interaction between microwave and material,but also provide a possible guide for the experiment of microwave-assisted extraction.

关键词： microwave-assisted extraction microwave heating relaxation time liquid viscosity peak absorption fre-quency

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 Tianjin 300071 China

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

Exact eigenstates for a class of models describing multiphoton processes in the presence of seven bosonic modes

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Science china(physics,Mechanics & Astronomy) 2004年第6期47卷 649-657页

作者： ZHAN Zhiming1,LI Weibin2,YOU Jun2,XIE Xiaotao2 & YANG Wenxing2 1.State Key Laboratory of Laser Technology,Huazhong university of Science and Technology,Wuhan 430074,china 2.department of physics,Huazhong university of Science and Technology,Wuhan 430074,china State Key Laboratory of Laser Technology Huazhong University of Science and Technology Wuhan 430074 China department of physics Huazhong University of Science and Technology Wuhan 430074 China

We present the analytical expressions of eigenstates and eigenenergies by using a parameter λ without the assumption of Bethe anzatz for three kinds of seven-bosonic-mode mixing models. The parameter is shown to be determined by the roots of a simple polynomial. We also demonstrate the exact analytical expressions of eigenstates and energies without any unknown parameter.

关键词： spectra, eigenstate, eigenvalue.

The size effect on transport properties of colossal magnetoresistance materials La_(0.67)Ca_(0.33)MnO_3

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Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 251-257页

作者： LI PeiGang1,2,LEI Ming1,2,GUO YanFeng2,GUO Xi2,CHEN LeiMing2, TANG WeiHua1,2,SONG PengYun3 & CHEN JinPing3 1 department of physics,Center for Optoelectronics Materials and Devices,Zhejiang Sci-Tech university,Hangzhou 310018,china 2 National Laboratory for Condensed Matter physics,Institute of physics,Chinese Academy of Sciences,Beijing 100080,china 3 department of physics,Peking university,Beijing 100875,china department of physics Center for Optoelectronics Materials and Devices Zhejiang Sci-Tech University Hangzhou China National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China department of physics Peking University Beijing China

High quality La0.67Ca0.33MnO3 (LCMO) film was deposited via a novel pulsed electron deposition technique on SrTiO3(100) single crystal substrate. The micro-bridge with different widths was fabricated by using electron beam lithography (EBL) technique and their transport properties were studied. For the micro-bridges with width of 2 and 1.5 μm,the insulator-to-metal transition temperature (TP) keeps un-changed compared with the film. For the micro-bridges with width of 1 μm,the TP shifts towards the lower temperature by 50 K. When the width decreases down to 500 nm,the insulator-to-metal transition disappears. The magnetoresistance be-havior of these micro-bridges was studied,and the results show that the low field magnetoresistance (LFMR) decreases and the high field magnetoresistances (HFMR) keep almost unchanged as the width of micro-bridge is reduced.

关键词： colossal magnetoresistance pulsed electron deposition electron beam lithography electrical transport properties