Taking into account correlations in a layered two-dimensional（2D）Fermi liquid,aCoulomb-type interaction induces pairing if particle-hole excitations are taken into account.The quasi-particle pairing force is analogo...Taking into account correlations in a layered two-dimensional（2D）Fermi liquid,aCoulomb-type interaction induces pairing if particle-hole excitations are taken into account.The quasi-particle pairing force is analogous to the resonating valence bond（RVB）of elec-trons in a hydrogen or positronium molecule-like structure.It is turned out that scatteringdiagrams from this model allow to evaluate the vertex function Γ.T<sub>c</sub> is hence calculated byusing the pole condition Γ<sup>-1</sup>=0.It has been found out that T<sub>c</sub> can reach quite high values andgives rise to the bell shape,and is related to the particle density,interlayer distance,dielec-tric constant and band mass.PACS numbers:74.65.+n,71.45.Gm.,74.70.Jm.,71.45.Lr.展开更多
In this research, the influence of calcium content on the binding energy and Cooper pairing is investigated for the high temperature superconducting Y1-xCaxBa2Cu3O7-δ compound where x = 0 - 0.2). This is done by usin...In this research, the influence of calcium content on the binding energy and Cooper pairing is investigated for the high temperature superconducting Y1-xCaxBa2Cu3O7-δ compound where x = 0 - 0.2). This is done by using model considering that the formation of Cooper pairs happens during tunneling mechanism of holes between the two CuO2 layers in the YCBCO crystal which are considered as forming adjacent potential wells. In this work, we make some modifications on the mentioned model and a modified equation for the binding energy as a function of Ca concentration is formulated to study the effect of Ca content by considering the change in the distance between the CuO2 layer as a function of Ca. The calculated results agree very well with experimental results. This happens because the Ca2+ substitution for Y3+ leads to decreasing the distance between the two CuO2 layers and hence potential energy of the system will be decreased. This leads to decreasing the binding energy between the Cooper pairs, and decreasing the distance between the two CuO2 layers increasing the tunneling probability of holes between the two CuO2 layers and thus increasing conduction mechanism and thus increasing current density, but this will decrease the energy gap and as a result decrease the critical temperature. The calculated results agree very well with experimental results.展开更多
The dynamics of the skew information (SI) is investigated for a single Cooper Pair Box (CPB) interacting with a single cavity field. By suitably choosing the system parameters and precisely controlling the dynamics, n...The dynamics of the skew information (SI) is investigated for a single Cooper Pair Box (CPB) interacting with a single cavity field. By suitably choosing the system parameters and precisely controlling the dynamics, novel connection is found between the SI and entanglement generation. It is shown that SI can be increased and reach its maximum value either by increasing the number of photons inside the cavity or considering the far off-resonant case.The number of oscillations of SI is increased by decreasing this ratio between the Josephson junction capacity and the gate capacity. This leads to significant improvement of the travelling time between the maximum and minimum values.展开更多
This paper examines the quantization of mesoscopic circuit including Josephson junctions. Following Feynman＇s assumption, via the Hamilton dynamic approach and by virtue of the entangled state representation, it cons...This paper examines the quantization of mesoscopic circuit including Josephson junctions. Following Feynman＇s assumption, via the Hamilton dynamic approach and by virtue of the entangled state representation, it constructs Hamiltonian operator for the double-Josephson-junction mesoscopic circuit coupled by a capacitor. Then it uses the Heisenberg equation of motion to derive the induction voltage across each Josephson junction. The result manifestly shows how the voltage is affected by the capacitance coupling.展开更多
A Cooper-pair box biased by a classical voltage and also irradiated by a squeezed state field is considered in order to find new ways to quantum communication and calculation. The quantum dynamics of the Cooper-pair b...A Cooper-pair box biased by a classical voltage and also irradiated by a squeezed state field is considered in order to find new ways to quantum communication and calculation. The quantum dynamics of the Cooper-pair box and the entanglement which is the core theoretics of quantum communication and calculation is investigated in this system, which is related to the squeezing parameter of the squeezed state, A model of Hamiltonian which represents the interaction between box and quantum field is introduced. Finally, the relationship between the entanglement and the squeezing parameter of the squeezed state is demonstrated.展开更多
A Hamiltonian which represents the interaction between a single Cooper-pair box and two quantized electromagnetic fields is considered in order to find new ways for quantum information. The wave function in Schrodinge...A Hamiltonian which represents the interaction between a single Cooper-pair box and two quantized electromagnetic fields is considered in order to find new ways for quantum information. The wave function in Schrodinger picture is obtained. The evolution of the entropy of the box as a function of the scaled time is ploted to measure the entanglement between the box and the fields. It is found that the entanglement is sensitive to the detuning between the Josephson energy and the fields frequency, increasing the detuning can decrease the entanglement.展开更多
The Ising spin–orbit coupling could give rise to the spin-triplet Cooper pairs and equal-spin Andreev reflection(AR)in Ising superconductors.Here we theoretically study the valley-dependent equal-spin AR in a ferroma...The Ising spin–orbit coupling could give rise to the spin-triplet Cooper pairs and equal-spin Andreev reflection(AR)in Ising superconductors.Here we theoretically study the valley-dependent equal-spin AR in a ferromagnet/Ising superconductor junction with a circularly polarized light applied to the ferromagnet.Because of the spin-triplet Cooper pairs and the optical irradiation,eight kinds of AR processes appear in the junction,including equal-spin AR and normal AR,the strengths and properties of which strongly depend on the valley degree of freedom.The AR probabilities for the incident electron from the two valleys exhibit certain symmetry with respect to the magnetization angle and the effective energy of light.The equal-spin AR and normal AR present different features and resonant behaviors near the superconducting gap edges.Due to equal-spin-triplet Cooper pairs,not only charge supercurrent but also spin supercurrent can transport in the Ising superconductors.The differential spin conductance for electron injecting from the two valleys can be controlled by the circularly polarized light.展开更多
We propose that the exotic meson tetraquark u<sub>d</sub>~</sup>dũintroduced in previous papers, may be a pseudo-Goldstone boson having a tetrahedron geometry and symmetry. The transition ...We propose that the exotic meson tetraquark u<sub>d</sub>~</sup>dũintroduced in previous papers, may be a pseudo-Goldstone boson having a tetrahedron geometry and symmetry. The transition from the neutral pion superposition of two free mesons, d<sub>d</sub>~</sup> and uũ, to the tetrahedron geometry with optional two chiral states may be the symmetry breaking of the QCD ground state. The u<sub>d</sub>~</sup>dũtetrahedron mass may be calculated by measuring the β decay rate variability. We assume that electrons and positrons are composite particle exotic tetraquarks, dũd<sub>d</sub>~</sup> for the electrons and u<sub>d</sub>~</sup>d<sub>d</sub>~</sup> for the positrons and confined by the strong force. We propose that the QCD tetrahedrons play a central role in electron pairing mechanism in both chemical bond forming and superconductor Cooper pairs. We propose a hypothesis where the QCD ground state tetrahedrons play a central role in low energy physics where quark exchange reactions between particles and the QCD tetrahedrons via gluon junctions transfer all the forces. The QCD ground state u<sub>d</sub>~</sup>dũtetrahedrons hypothesis provides a symmetry breaking and a mass gap may be created by the ground state QCD tetrahedrons Bose-Einstein condensate.展开更多
This paper discusses cross-border cooperation at the level of urban socio-economic systems. Worldwide, cross-border urban cooperation has in several cases produced socio-economic and political coherence supported by v...This paper discusses cross-border cooperation at the level of urban socio-economic systems. Worldwide, cross-border urban cooperation has in several cases produced socio-economic and political coherence supported by various joint programs and efforts. However, the degree of coherence varies and seldom cre-ates socio-economically and politically tightly integrated "Twin-Cities" where the state border becomes highly transparent or ob-scure. Focusing on Finlan d and China, our aim is to identify whether the selected border towns represent coherent TwinCities or a more loose type of "paired border towns". The study uses an empirical examination of three Finnish towns (Helsinki, Tornio, Imatra) and their neighboring towns in Estonia, Sweden, and Rus-sia as a benchmark. Then, a comparative study is made regarding three Chinese cross-border cities facing Russia, Vietnam and Ka-zakhstan. We highlight the differences in cross-border integration from the viewpoint of shared public sector programs, cross-border enterprise relocation and networking, and integrated social sector in terms of labor market, education and shopping area.展开更多
基金Supported by Doe through Science Engineering Alliance under the grant No.DE-FG05-94ER25229The numerical calculations were performed on the CRY supercomputer provided by NCSA at UIUC.
文摘Taking into account correlations in a layered two-dimensional（2D）Fermi liquid,aCoulomb-type interaction induces pairing if particle-hole excitations are taken into account.The quasi-particle pairing force is analogous to the resonating valence bond（RVB）of elec-trons in a hydrogen or positronium molecule-like structure.It is turned out that scatteringdiagrams from this model allow to evaluate the vertex function Γ.T<sub>c</sub> is hence calculated byusing the pole condition Γ<sup>-1</sup>=0.It has been found out that T<sub>c</sub> can reach quite high values andgives rise to the bell shape,and is related to the particle density,interlayer distance,dielec-tric constant and band mass.PACS numbers:74.65.+n,71.45.Gm.,74.70.Jm.,71.45.Lr.
文摘In this research, the influence of calcium content on the binding energy and Cooper pairing is investigated for the high temperature superconducting Y1-xCaxBa2Cu3O7-δ compound where x = 0 - 0.2). This is done by using model considering that the formation of Cooper pairs happens during tunneling mechanism of holes between the two CuO2 layers in the YCBCO crystal which are considered as forming adjacent potential wells. In this work, we make some modifications on the mentioned model and a modified equation for the binding energy as a function of Ca concentration is formulated to study the effect of Ca content by considering the change in the distance between the CuO2 layer as a function of Ca. The calculated results agree very well with experimental results. This happens because the Ca2+ substitution for Y3+ leads to decreasing the distance between the two CuO2 layers and hence potential energy of the system will be decreased. This leads to decreasing the binding energy between the Cooper pairs, and decreasing the distance between the two CuO2 layers increasing the tunneling probability of holes between the two CuO2 layers and thus increasing conduction mechanism and thus increasing current density, but this will decrease the energy gap and as a result decrease the critical temperature. The calculated results agree very well with experimental results.
文摘The dynamics of the skew information (SI) is investigated for a single Cooper Pair Box (CPB) interacting with a single cavity field. By suitably choosing the system parameters and precisely controlling the dynamics, novel connection is found between the SI and entanglement generation. It is shown that SI can be increased and reach its maximum value either by increasing the number of photons inside the cavity or considering the far off-resonant case.The number of oscillations of SI is increased by decreasing this ratio between the Josephson junction capacity and the gate capacity. This leads to significant improvement of the travelling time between the maximum and minimum values.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574060)the Natural Science Foundation(Grant No Y2004A09) of Shandong Province,China
文摘This paper examines the quantization of mesoscopic circuit including Josephson junctions. Following Feynman＇s assumption, via the Hamilton dynamic approach and by virtue of the entangled state representation, it constructs Hamiltonian operator for the double-Josephson-junction mesoscopic circuit coupled by a capacitor. Then it uses the Heisenberg equation of motion to derive the induction voltage across each Josephson junction. The result manifestly shows how the voltage is affected by the capacitance coupling.
文摘A Cooper-pair box biased by a classical voltage and also irradiated by a squeezed state field is considered in order to find new ways to quantum communication and calculation. The quantum dynamics of the Cooper-pair box and the entanglement which is the core theoretics of quantum communication and calculation is investigated in this system, which is related to the squeezing parameter of the squeezed state, A model of Hamiltonian which represents the interaction between box and quantum field is introduced. Finally, the relationship between the entanglement and the squeezing parameter of the squeezed state is demonstrated.
文摘A Hamiltonian which represents the interaction between a single Cooper-pair box and two quantized electromagnetic fields is considered in order to find new ways for quantum information. The wave function in Schrodinger picture is obtained. The evolution of the entropy of the box as a function of the scaled time is ploted to measure the entanglement between the box and the fields. It is found that the entanglement is sensitive to the detuning between the Josephson energy and the fields frequency, increasing the detuning can decrease the entanglement.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974153,12374034 and 11921005)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302403)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)。
文摘The Ising spin–orbit coupling could give rise to the spin-triplet Cooper pairs and equal-spin Andreev reflection(AR)in Ising superconductors.Here we theoretically study the valley-dependent equal-spin AR in a ferromagnet/Ising superconductor junction with a circularly polarized light applied to the ferromagnet.Because of the spin-triplet Cooper pairs and the optical irradiation,eight kinds of AR processes appear in the junction,including equal-spin AR and normal AR,the strengths and properties of which strongly depend on the valley degree of freedom.The AR probabilities for the incident electron from the two valleys exhibit certain symmetry with respect to the magnetization angle and the effective energy of light.The equal-spin AR and normal AR present different features and resonant behaviors near the superconducting gap edges.Due to equal-spin-triplet Cooper pairs,not only charge supercurrent but also spin supercurrent can transport in the Ising superconductors.The differential spin conductance for electron injecting from the two valleys can be controlled by the circularly polarized light.
文摘We propose that the exotic meson tetraquark u<sub>d</sub>~</sup>dũintroduced in previous papers, may be a pseudo-Goldstone boson having a tetrahedron geometry and symmetry. The transition from the neutral pion superposition of two free mesons, d<sub>d</sub>~</sup> and uũ, to the tetrahedron geometry with optional two chiral states may be the symmetry breaking of the QCD ground state. The u<sub>d</sub>~</sup>dũtetrahedron mass may be calculated by measuring the β decay rate variability. We assume that electrons and positrons are composite particle exotic tetraquarks, dũd<sub>d</sub>~</sup> for the electrons and u<sub>d</sub>~</sup>d<sub>d</sub>~</sup> for the positrons and confined by the strong force. We propose that the QCD tetrahedrons play a central role in electron pairing mechanism in both chemical bond forming and superconductor Cooper pairs. We propose a hypothesis where the QCD ground state tetrahedrons play a central role in low energy physics where quark exchange reactions between particles and the QCD tetrahedrons via gluon junctions transfer all the forces. The QCD ground state u<sub>d</sub>~</sup>dũtetrahedrons hypothesis provides a symmetry breaking and a mass gap may be created by the ground state QCD tetrahedrons Bose-Einstein condensate.
文摘This paper discusses cross-border cooperation at the level of urban socio-economic systems. Worldwide, cross-border urban cooperation has in several cases produced socio-economic and political coherence supported by various joint programs and efforts. However, the degree of coherence varies and seldom cre-ates socio-economically and politically tightly integrated "Twin-Cities" where the state border becomes highly transparent or ob-scure. Focusing on Finlan d and China, our aim is to identify whether the selected border towns represent coherent TwinCities or a more loose type of "paired border towns". The study uses an empirical examination of three Finnish towns (Helsinki, Tornio, Imatra) and their neighboring towns in Estonia, Sweden, and Rus-sia as a benchmark. Then, a comparative study is made regarding three Chinese cross-border cities facing Russia, Vietnam and Ka-zakhstan. We highlight the differences in cross-border integration from the viewpoint of shared public sector programs, cross-border enterprise relocation and networking, and integrated social sector in terms of labor market, education and shopping area.
