The explicit form of the evolution operator for the three-atom Tavis-Cummings model is given. The atoms can be entangled through their interaction with a thermal field. The degree of entanglement depends on the mean p...The explicit form of the evolution operator for the three-atom Tavis-Cummings model is given. The atoms can be entangled through their interaction with a thermal field. The degree of entanglement depends on the mean photon number of the thermal field and the initial state of the atoms.展开更多
Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field a...Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field and Dzyaloshinski-Moriya interaction are the more efficient control parameters for the increase of entanglement and critical temperature. For both the nearest neighbour sites and the next nearest neighbour sites, the magnetic field can induce entanglement to a certain extent and the Dzyaloshinski-Moriya interaction can enhance the entanglement to a stable value. The steady value of the nearest neighbour site entanglement C12 is larger than the next nearest neighbour site entanglement C13. An interesting phenomenon is that the entanglement curve of C12 appears a peak value when the Dzyaloshinski-Moriya interaction is considered in a nonuniform magnetic field.展开更多
We investigate the effects of the directions of Dzyaloshinskii Moriya (DM) interaction and magnetic field on the thermal entanglement in the pure DM model. It is found that when the Hamiltonian is H1 = D. (σ1 +σ...We investigate the effects of the directions of Dzyaloshinskii Moriya (DM) interaction and magnetic field on the thermal entanglement in the pure DM model. It is found that when the Hamiltonian is H1 = D. (σ1 +σ2) +B.σ1, the entanglement can reach its maximum if the directions of the magnetic field and the DM vector are parallel. In addition, when the Hamiltonian is H2 = D @ (σ1 σ2) + B. (σ1 + σ2), if the directions of the magnetic field and the DM vector are perpendicular in a high magnetic field, or their directions are parMlel in a weak magnetic field, the entanglement can also reach its maximum. Thus the entanglement can be enhanced by adjusting the direction of the external magnetic field, and this is feasible within the current experimental technology.展开更多
The ring-banded spherulite is a special morphology of polymer crystals and has attracted considerable attention over recent decades. In this study, a new phase field model with polymer characteristics is established t...The ring-banded spherulite is a special morphology of polymer crystals and has attracted considerable attention over recent decades. In this study, a new phase field model with polymer characteristics is established to investigate the emergence and formation mechanism of the ring-banded spherulites of crystalline polymers. The model consists of a nonconserved phase field representing the phase transition and a temperature field describing the diffusion of the released latent heat. The corresponding model parameters can be obtained from experimentally accessible material parameters.Two-dimensional calculations are carried out for the ring-banded spherulitic growth of polyethylene film under a series of crystallization temperatures. The results of these calculations demonstrate that the formation of ring-banded spherulites can be triggered by the self-generated thermal field. Moreover, some temperature-dependent characteristics of the ring-banded spherulites observed in experiments are reproduced by simulations, which may help to study the effects of crystallization temperature on the ring-banded structures.展开更多
The thermal entanglement of a two-qutrit spin-1 anisotropic Heisenberg XXZ chain in an inhomogeneous magnetic field is studied in detail. The effects of the external magnetic field (B), a parameter b which controls ...The thermal entanglement of a two-qutrit spin-1 anisotropic Heisenberg XXZ chain in an inhomogeneous magnetic field is studied in detail. The effects of the external magnetic field (B), a parameter b which controls the inhomogeneity of B, and the bilinear interaction parameters Jx = Jy ≠ Jz on the thermal variation of the negativity are studied in detail. It is found that negativity N decreases when the values of magnetic field, inhomogeneity b and temperature are increasing. In addition, N remains at higher temperatures for higher values of Jz and lower values of B and b.展开更多
The electric transmission system congfiguration-2 is one of the main electric drives for tracked vehicles. The geometrical model for the power-train cabin is established and the preliminary design for its cooling syst...The electric transmission system congfiguration-2 is one of the main electric drives for tracked vehicles. The geometrical model for the power-train cabin is established and the preliminary design for its cooling system is implemented. The mathematic model is established for thermal current field computation, simulation and analysis in the powertrain cabin. The three-dimensional structure of the powertrain cabin is optimized. The validity of the cooling system design is proved. The foundation for optimizing the whole electric transmission system configuration is laid.展开更多
有不同不同类的磁场的一个 two-qubit Heisenberg XYZ 模型的热纠纷上的纺纱纺纱相互作用的效果被调查。纠纷依赖于纺纱纺纱相互作用和不同类的磁场,这被显示出。越大 Ji (i 轴纺纱纺纱相互作用) ,越 higher 批评价值双性人(i 轴制服...有不同不同类的磁场的一个 two-qubit Heisenberg XYZ 模型的热纠纷上的纺纱纺纱相互作用的效果被调查。纠纷依赖于纺纱纺纱相互作用和不同类的磁场,这被显示出。越大 Ji (i 轴纺纱纺纱相互作用) ,越 higher 批评价值双性人(i 轴制服磁场) 有。而且在弱地的政体,,更大的 Ji 在强壮地的政体对应于更多的纠纷,不同 Ji 对应于一样的纠纷。另外,随 Ji 的增加,同时发生能为更小的双性人更快接近最大的价值,这被发现,并且能为更小的双性人到达更大的价值(i 轴不一致的磁场) 。我们能因此由增加纺纱纺纱相互作用 Ji,或由减少得到更多的纠纷一致磁场双性人和不一致的磁场双性人。展开更多
A heat source model for radial friction welding was proposed, which was determined by friction pressure, friction coefficient, material properties and extrusion speed of material. A 3D model was established to analyze...A heat source model for radial friction welding was proposed, which was determined by friction pressure, friction coefficient, material properties and extrusion speed of material. A 3D model was established to analyze the continuous drive radial friction welding temperature field of 45 steel pipe. The influences of friction pressure, friction time and rotation speed on the temperature of the friction interface were analyzed. The results showed that the temperature on the friction interface rapidly rose to a peak temperature in initial friction stage and kept constant in the stable friction stage. Welding parameters of friction pressure, friction time and rotation speed had few influences on the peak temperature, while the increase of frlctlon pressure and rotation speed could shorten the time to reach the peak temperature.展开更多
We have proven the general relations between the gap equations obeyed by dynamical fermion mass and thecorresponding effective potentials at finite temperature and chemical potential in D-dimensional four-fermion inte...We have proven the general relations between the gap equations obeyed by dynamical fermion mass and thecorresponding effective potentials at finite temperature and chemical potential in D-dimensional four-fermion interactionmodels. This gives an easy approach to get effective potentials directly from the gap equations. We find out explicitexpressions for the effective potentials at zero temperature in the cases of D = 2,3, and 4 for practical use.展开更多
We re-examine physical causal propagators for scalar and pseudoscalar bound states at finite temperaturein a chiral Ut(1) x UR(1) NJL model, defined by four-point amputated fimctions subtracted through the gap equatio...We re-examine physical causal propagators for scalar and pseudoscalar bound states at finite temperaturein a chiral Ut(1) x UR(1) NJL model, defined by four-point amputated fimctions subtracted through the gap equation,and prove that they are completely equivalent in the imaginary-time and real-time formalisms by separating carefiullythe imaginary part of the zero-temperature loop integral. It is shown that the same thermal transformation matrix ofthe matrix propagators for these bound states in the real-time formalism is precisely the one of the matrix propagatorfor an elementary scalar particle and this fact shows the similarity of thermodynamic property between a composite andelementary scalar particle. The retarded and advanced propagators for these bound states are also given explicitly fromthe imaginary-time formalism.展开更多
文摘The explicit form of the evolution operator for the three-atom Tavis-Cummings model is given. The atoms can be entangled through their interaction with a thermal field. The degree of entanglement depends on the mean photon number of the thermal field and the initial state of the atoms.
文摘Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field and Dzyaloshinski-Moriya interaction are the more efficient control parameters for the increase of entanglement and critical temperature. For both the nearest neighbour sites and the next nearest neighbour sites, the magnetic field can induce entanglement to a certain extent and the Dzyaloshinski-Moriya interaction can enhance the entanglement to a stable value. The steady value of the nearest neighbour site entanglement C12 is larger than the next nearest neighbour site entanglement C13. An interesting phenomenon is that the entanglement curve of C12 appears a peak value when the Dzyaloshinski-Moriya interaction is considered in a nonuniform magnetic field.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11204061,11374085,11274010 and 11204002the Anhui Provincial Natural Science Foundation under Grant No 1408085MA16+4 种基金the China Postdoctoral Science Foundation under Grant No 20110490825the Key Project of the Ministry of Education of China under Grant No 211080the Key Program of the Education Department of Anhui Province under Grant Nos KJ2012A244 and KJ2012A020the Program of Hefei Normal University under Grant Nos 2012jd17,2013jd03 and 2014136KJC02the Excellent Young Talents Support Plan of Anhui Provincial Universities
文摘We investigate the effects of the directions of Dzyaloshinskii Moriya (DM) interaction and magnetic field on the thermal entanglement in the pure DM model. It is found that when the Hamiltonian is H1 = D. (σ1 +σ2) +B.σ1, the entanglement can reach its maximum if the directions of the magnetic field and the DM vector are parallel. In addition, when the Hamiltonian is H2 = D @ (σ1 σ2) + B. (σ1 + σ2), if the directions of the magnetic field and the DM vector are perpendicular in a high magnetic field, or their directions are parMlel in a weak magnetic field, the entanglement can also reach its maximum. Thus the entanglement can be enhanced by adjusting the direction of the external magnetic field, and this is feasible within the current experimental technology.
基金Project supported by the National Key Basic Research Program of China(Grant No.2012CB025903)the National Natural Science Foundation of China(Grant No.11402210)+1 种基金the Northwestern Polytechnical University Foundation for Fundamental Research(Grant No.JCY20130141)the Ministry of Education Fund for Doctoral Students Newcomer Awards of China
文摘The ring-banded spherulite is a special morphology of polymer crystals and has attracted considerable attention over recent decades. In this study, a new phase field model with polymer characteristics is established to investigate the emergence and formation mechanism of the ring-banded spherulites of crystalline polymers. The model consists of a nonconserved phase field representing the phase transition and a temperature field describing the diffusion of the released latent heat. The corresponding model parameters can be obtained from experimentally accessible material parameters.Two-dimensional calculations are carried out for the ring-banded spherulitic growth of polyethylene film under a series of crystallization temperatures. The results of these calculations demonstrate that the formation of ring-banded spherulites can be triggered by the self-generated thermal field. Moreover, some temperature-dependent characteristics of the ring-banded spherulites observed in experiments are reproduced by simulations, which may help to study the effects of crystallization temperature on the ring-banded structures.
文摘The thermal entanglement of a two-qutrit spin-1 anisotropic Heisenberg XXZ chain in an inhomogeneous magnetic field is studied in detail. The effects of the external magnetic field (B), a parameter b which controls the inhomogeneity of B, and the bilinear interaction parameters Jx = Jy ≠ Jz on the thermal variation of the negativity are studied in detail. It is found that negativity N decreases when the values of magnetic field, inhomogeneity b and temperature are increasing. In addition, N remains at higher temperatures for higher values of Jz and lower values of B and b.
文摘The electric transmission system congfiguration-2 is one of the main electric drives for tracked vehicles. The geometrical model for the power-train cabin is established and the preliminary design for its cooling system is implemented. The mathematic model is established for thermal current field computation, simulation and analysis in the powertrain cabin. The three-dimensional structure of the powertrain cabin is optimized. The validity of the cooling system design is proved. The foundation for optimizing the whole electric transmission system configuration is laid.
基金Supported by National Natural Science Foundation of China under Grant No. 10704001Anhui Provincial Natural Science Foundation under Grant No. 070412060+1 种基金the Major Program of the Education Department of Anhui Province under Grant No. KJ2010ZD08the Key Program of the Education Department of Anhui Province under Grant No. KJ2010A287
文摘有不同不同类的磁场的一个 two-qubit Heisenberg XYZ 模型的热纠纷上的纺纱纺纱相互作用的效果被调查。纠纷依赖于纺纱纺纱相互作用和不同类的磁场,这被显示出。越大 Ji (i 轴纺纱纺纱相互作用) ,越 higher 批评价值双性人(i 轴制服磁场) 有。而且在弱地的政体,,更大的 Ji 在强壮地的政体对应于更多的纠纷,不同 Ji 对应于一样的纠纷。另外,随 Ji 的增加,同时发生能为更小的双性人更快接近最大的价值,这被发现,并且能为更小的双性人到达更大的价值(i 轴不一致的磁场) 。我们能因此由增加纺纱纺纱相互作用 Ji,或由减少得到更多的纠纷一致磁场双性人和不一致的磁场双性人。
基金This work was suooorted by National Natural Science Foundation of China (Grant No. 51075174/E050803 ).
文摘A heat source model for radial friction welding was proposed, which was determined by friction pressure, friction coefficient, material properties and extrusion speed of material. A 3D model was established to analyze the continuous drive radial friction welding temperature field of 45 steel pipe. The influences of friction pressure, friction time and rotation speed on the temperature of the friction interface were analyzed. The results showed that the temperature on the friction interface rapidly rose to a peak temperature in initial friction stage and kept constant in the stable friction stage. Welding parameters of friction pressure, friction time and rotation speed had few influences on the peak temperature, while the increase of frlctlon pressure and rotation speed could shorten the time to reach the peak temperature.
文摘We have proven the general relations between the gap equations obeyed by dynamical fermion mass and thecorresponding effective potentials at finite temperature and chemical potential in D-dimensional four-fermion interactionmodels. This gives an easy approach to get effective potentials directly from the gap equations. We find out explicitexpressions for the effective potentials at zero temperature in the cases of D = 2,3, and 4 for practical use.
文摘We re-examine physical causal propagators for scalar and pseudoscalar bound states at finite temperaturein a chiral Ut(1) x UR(1) NJL model, defined by four-point amputated fimctions subtracted through the gap equation,and prove that they are completely equivalent in the imaginary-time and real-time formalisms by separating carefiullythe imaginary part of the zero-temperature loop integral. It is shown that the same thermal transformation matrix ofthe matrix propagators for these bound states in the real-time formalism is precisely the one of the matrix propagatorfor an elementary scalar particle and this fact shows the similarity of thermodynamic property between a composite andelementary scalar particle. The retarded and advanced propagators for these bound states are also given explicitly fromthe imaginary-time formalism.