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59. Melting Curve of Metals: Pressure Dependence Vu Van Hung (1), Dang Thanh Hai (2), and Le Thi Binh (1) (1) Hanoi National University of Education, 136 Xuanthuy, Caugiay, Hanoi (2) Vietnam Education Publishing House, Tran Hung Dao, Hai Ba Trung, Ha Noi The high-pressure melting curve of metals has been studied using the statistical moment method. The melting was investigated at different high pressures, the melting temperature being in good agreement with previous experiments and several theoretical calculations. A small slope for the melting dT/dP curve of metals is estimated and a possible explanation for this behaviour is given. Finally, a P -V - T equation of states is obtained, the temperature and pressure dependences of the shear modulus and the bulk modulus being estimated. Báo cáo Treo 60. Investigation of Thermodynamic Properties Liquid Cu – Ni Alloys Using Moment Method Nguyen Thanh Hai Institute of Engineering Physics, Hanoi University of Technology, 1 Dai Co Viet, Hai Ba Trung, Ha Noi Using the model of liquid alloys having structural similar solid alloys at melting temperature, the expressions nearest-neighbour distance of liquid alloy are obtained. The change in volume, entropy, specific heat of alloys on melting at the pressure P=0 is investigated. Our obtain results are applied to numerical calculations Báo cáo Treo 61. Study of Thermodynamic Properties of Zirconium under High Pressure Vu Van Hung, Le Dinh Hong, and Nguyen Thu Ha Hanoi University of Education 136 Xuan Thuy, Cau Giay, Ha Noi The moment method in statistical (SMM) dynamics is used to study the thermodynamic quantities of zirconium taking into account the anharmonicity effects of the lattice vibrations and hydrostatic Hội nghị Vật lý lý thuyết toàn quốc lần thứ 35 61 pressures. The thermodynamic quantities of zirconium are calculated as a function of the pressure. The SMM calculations are performed by using the Lennard-Jones potential for the zirconium crystal with hcp and bcc structures. Numerical results for lattice parameter, thermal expansion coefficient, specific heats at constant volume and those at the constant pressure CV and CP of zirconium crystal with bcc and hcp structures are found to be in good agreement with experiment. Báo cáo Treo 62. Study of Elastic Properties of CeO 2 by Statistical Moment Method Vu Van Hung (1), Le Thi Mai Thanh(1), and K. Masuda-Jindo (2) (1)Hanoi National University of Education, 136 Xuan Thuy, Hanoi, Vietnam (2) Department of Material Science and Engineering, Tokyo Institute of Technology, Nagasuta, Midori-ku, Yokohama 226-8530, Japan The purpose of the present article is to investigate the temperature and pressure dependences of the elastic properties of cerium dioxide using the statistical moment method (SMM). The equation of states of bulk CeO 2 is derived from the Helmholtz free energy, and the pressure dependences of the elastic moduli like the bulk modulus, BT, shear modulus, G, Young’s modulus, E, and elastic constants (C11, C12 and C44) are presented taking into account the anharmonicity effects of the thermal lattice vibrations. In the present study, the influence of temperature and pressure on the elastic moduli and elastic constants of CeO 2 have also been studied, using three different interatomic potentials.. We compare the results of the present calculations with those of the previous theoretial calculations as well as with the available experiments Báo cáo Treo 63. Structural and Dynamics Properties of Lithium Silicate Nguyen Thu Nhan and Pham Khac Hung Department of Computational Physics, Hanoi University of Science and Technology, Vietnam 62 Tp. Hồ Chí Minh, 02-06/8/2010 The diffusion mechanism in silicate melts is a long debated topic in material science. The present paper focuses on to give new insight in this problem based on the comparative study for pure and lithium silicate melts (SiO 2 and (Li 2 O) 0.1 .(SiO 2 ) 0.9 ). Both silicate models consisting of 3000 atoms have been prepared at ambient pressure and temperature from 1500 to 4000 K. The simulation reveals a significant difference in the tetrahedral-network structures which results in the change in the diffusion mechanism of silicon and oxygen. The local structure of both melts is also analyzed and discussed here. Báo cáo Treo 64. Order – Disorder Phase Transition in Cu 3 Au under Pressure Pham Dinh Tam (1), Nguyen Quang Hoc (2), Le Tien Hai (1), and Pham Duy Tan (1) (1) Le Quy Don University of Technology, 100 Hoang Quoc Viet, Cau Giay, Hanoi (2) Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi The dependence of the critical temperature Tc for alloy Cu 3 Au on pressure in the interval from 0 to 30 kbar is studied by the statistical moment method. The calculated velocity of critical temperature changing to pressure is 2.1K/ kbar in the interval from 7 to 21 kbar and this result is in a good agreement with the experimental data. Báo cáo Treo 65. Study of Elastic Properties of Quantum Crystals by Statistical Moment Method Vu Van Hung, Hoang Van Thai, and Dinh Quang Vinh Hanoi National University of Education, 136 Xuan Thuy, Hanoi, Vietnam Temperature and pressure dependences of the elastic properties of quantum crystals have been studied using the analytic statistical moment method (SMM). The equation of states of the quantum crystals is derived from the Helmholtz free energy, and the pressure dependences of the elastic moduli like the bulk modulus, BT, shear modulus, G, Young’s modulus, E, and elastic constants (C11, C12 63 Hội nghị Vật lý lý thuyết toàn quốc lần thứ 35 64 and C44) are presented taking into account the anharmonicity effects of the thermal lattice vibrations. In the present study, the influence of temperature and pressure on the elastic moduli and elastic constants of Ar, Kr, and Xe have also been studied, using the Lennard-Jones potentials and we compare the SMM results with those of the previous theoretial calculations as well as with the available experimental results. Báo cáo Treo 66. A Thermodynamic Lattice Theory on Lindemann’s Melting Temperature and Eutectic Point of FCC Binary Alloys Nguyen Van Hung, Nguyen Cong Toan, Tong Sy Tien, Nguyen Bao Trung Department of Physics, University of Science, VNU-Hanoi. 334 Nguyen Trai, Thanh Xuan, Hanoi A thermodynamic lattice theory has been developed for determination of the melting curves and eutectic points of fcc binary alloys. Based on Lindemann’s criterion the analytical expressions for the ratio of root mean square fluctuation in atomic positions on the equilibrium lattice positions and the nearest neighbor distance, and then from which those for the melting curves of binary alloys composed by fcc constituent elements have been derived. This melting curve provides information on Lindemann’s melting temperatures of binary alloys with respect to any proportion of constituent elements and on their eutectic points. Numerical results for some fcc binary alloys provide a good correspondence between the calculated and experimental phase diagrams, where the calculated results for Cu 1-x Ni x agree well with the measured values. Báo cáo Treo 67. Atomic Radii of Noble Gas Elements in Condensed Phases Nguyen Quang Hoc and Dinh Quang Vinh Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi Neutral atomic radii of dissolved noble gas elements in condensed phases are obtained by treating the neutral atoms as “ions” of zero Tp. Hồ Chí Minh, 02-06/8/2010
oxidation state and by interpolating from a plot of radius vs. oxidation state for isoelectronic ions. The major assumption is that the radius of an ion or a neutral atom having an electronic configuration of noble gas elements depends primarily on the interaction between the nucleus and the surrounding electrons and not on the interaction between the ion and its neighbours. As expected, the values of the new set of radii are slightly greater than the univalent radii and smaller than the radii of noble atoms in their crystals in which the coordination number is 12 Báo cáo Treo IV. Vật lý lượng tử, quang lượng tử, thông tin lượng tử 68. Engineered Spin Chains for Perfect Quantum State Transfer Nguyen Van Hieu and Nguyen Bich Ha Max-Planck Institute for the Physics of Complex Systems, Dresden, Germany and Institute of Materials Science, Vietnam Academy of Science and Technology For the application to the quantum information processing technology the quantum state transfer (QST) between two directly interacting qubits as well as between two distant ones interacting through the intermediary of different quantum systems were widely considered. As the intermediary system it was proposed to use that of photons in an optical fiber for the case of the QST between two quantum dots placed inside two microcavities connected through this optical fiber [1-4], or a network of interacting spins in the case of the QST between two spin-qubits interacting with this network [5-10]. It is known that the perfect QST from one end of a homogeneous N-qubit chain to another is possible only for N = 2 and 3. In order to achieve the perfect QST it was proposed to use engineered spin chains with untunable but modulated coupling between adjacent spins, and a special version of engineered spin chains allowing the perfect QST was found in literature. The purpose of this work is to establish a wide class of engineered inhomogeneous mirror-symmetric N-spin chains with modulated untunable couplings which can provide the perfect QST between two ends of each chain. It includes as special cases the spin chains previously proposed. The sufficient conditions for the engineered mirror-symmetric spin chains allowing the perfect QST are derived. From these conditions the algebraic equations determining physical parameters of these spin chains are established. By solving these equations we can obtain the sets of values of these physical parameters. Examples of the chains with even and odd numbers of spins are presented. References [1] Cirac J I, Zoller P, Kimble H J and Mabuchi H 1997 Phys. Rev. Lett. 78 3221 [2] Pellizzari T 1997 Phys. Rev. Lett. 79 5242 [3] Serafini A, Mancini S and Bose S 2006 Phys. Rev. Lett. 96 010503 [4] Nguyen Van Hieu, Nguyen Bich Ha and Duong Hai Trieu 2010 Adv. Nat. Sci.: Nanosci. Nanotechnol. 1 015001 [5] Lloyd S 2003 Phys. Hội nghị Vật lý lý thuyết toàn quốc lần thứ 35 65 66 Tp. Hồ Chí Minh, 02-06/8/2010 Rev. Lett. 90 167902 [6] Bose S 2003 Phys. Rev. Lett. 91 207901 [7] Christandl M, Datta N Ekert A and Landahl A J 2004 Phys. Rev. Lett. 92 187902 [8] Albanese C, Christandl M, Data N and Ekert A 2004 Phys. Rev. Lett. 93 230502 [9] Karbach P and Stolze J 2005 Phys. Rev. A 72 030301 [10] Nguyen Van Hieu 2009 J. Phys.: Condens. Matt. 21 273201 Báo cáo Mời 69. Detecting Entanglement with non-Hermitian Operators Ho Trung Dung Ho Chi Minh city Institute of Physics, 1 Mac Dinh Chi Str., District 1, Ho Chi Minh city, Vietnam We derive several entanglement conditions employing nonhermitian operators. We start with two conditions that were derived previously for field mode operators, and use them to derive conditions that can be used to show the existence of field-atom entanglement and entanglement between groups of atoms. The original conditions can be strengthened by making them invariant under certain sets of local unitary transformations, such as Gaussian operations. We then apply these conditions to several examples, such as the Dicke model. Further, we present conditions that allow us to determine whether blocks of spins are entangled. We show that sometimes these conditions can detect entanglement better than conditions involving individual spins. We apply these conditions to study entanglement in spin wave states, both when there are only a few magnons present and also at finite temperature. Báo cáo Miệng 70. Construction of Potential Energy Curves for Diatomic Molecules by the Inverted Perturbation Approach. Dinh Xuan Khoa(1), Nguyen Tien Dung(1), Pham Van Trong(2), and Nguyen Huy <strong>Ban</strong>g(1) (1)Vinh University, 182 Le Duan Street, Vinh City, Vietnam; (2) Hong Duc University, Thanh Hoa, Vietnam. Knowing of potential energy curves (PEC) of diatomic molecules plays important role in atomic and molecular physics because it can provide information for prediction of atomic colissions, chemical bondings, and dispersion forces. Construction of PECs from Hội nghị Vật lý lý thuyết toàn quốc lần thứ 35 67 experimental data therefore attracts great attention of spectroscopists. There are revelral ways to archieve this goal. Perhaps the simplest one is to fit the data to the simple Morse function in which only two adjustable parameters to be determined. More adjustable parameters can be introduced to get more flexible form of PEC, but however for modern accurate spectroscopic measurements such models are not sufficient enough for interpretation of overal data. Up-to-date, the most efficient method for construction of a PEC which is satisfy a given accurate demand is the Inverted Perturbation Approach (IPA). The method was proposed by Kosman et al [1] and Vidal et al [2] and then developed by Pashov et al [3] as a fully quantum mechanical method for searching an accurate potential energy curve of a diatomic molecular state. In this paper we present the IPA method and discuss its aspects for construction of PEC of diatomic molecules. The method is then applied to the 4Pi state of NaLi molecule. Here, the previous PEC which was determined numerically by the semi-classical Rydberg-Klein-Rees method reported in the previous work [4] is employed as a trial function in the IPA procedure to search an optimum potential energy. The final IPA potential confirms results determined by recent theoretical ab initio calculations [5]. References [1] W. Kosman et al., J. Mol. Spectrosc. 56 (1975) 93. [2] C. Vidal et al., J. Mol. Spectrosc. 65 (1977) 46. [3] A. Pashov et al., Comput. Phys. Commun 128 (2000) 622. [4] Nguyen Huy <strong>Ban</strong>g et al., Chem. Phys. Lett, 440 (2007) 199. [5] N. Mabrouk et al., J. Phys. B: At. Mol. Opt.Phys. 41 (2008) 155101. Báo cáo Miệng 71. Distributuion of the Laser Intensity and the Force acting on Dielectric Nano-Particle in the 3D-Optical Trap using Counterpropagating Pulsed Laser Beams Ho Quang Quy (1), Bui Sy Khiem (2), Nguyen Thi Ha Trang (3), Chu Van Lanh (3) (1) Academy of Military Science & Technology, Hoang Quoc Viet, Cau Giay, Ha Noi (2) Second High Secondary School of Tinhgia, Thanhhoa (3) University of Vinh, Le Duan, Vinh, Nghe An 68 Tp. Hồ Chí Minh, 02-06/8/2010
Page 1 and 2: HỘI NGHỊ VẬT LÝ LÝ THUYẾT
Page 3 and 4: [P-11] Tran Nguyen Dung, Conductanc
Page 5 and 6: [P-49] Nguyen Nhu Dat, Frequency‐
Page 7 and 8: TÓM TẮT BÁO CÁO Hội nghị V
Page 9 and 10: 13. BRST - Invariant String Functio
Page 11 and 12: 28. Effects of Metallic Leads and S
Page 13 and 14: correlation length. The roughness-l
Page 15: due to SR counterpart. The differen
Page 19 and 20: Trường Đại Học Công Nghệ
Page 21 and 22: In this article, we propose a two-p
Page 23 and 24: are being extensively studied due t
Page 25 and 26: 4096 and 8192 atoms. The calculatio
Page 27 and 28: 141 Lưu Thị Kim Thanh luuthikim.
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