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We theoretically investigate properties of the ground state of a closed dot-ring system with a magnetic flux in the Kondo regime by means of a tight-banding Anderson Hamiltonian, using the Slave-Boson mean-field approach. The persistent current shows interesting dependences on the parity and on the size of the system. The signature of Kondo resonance at ζk/L = 0.15 is expected to be observed experimentally in the future. With the intensity of the coupling tD changes from weak to strong, the properties of the system changes largely, which are different from the in-line one because of the attached dot. 相似文献
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借助于共生纠缠度和输入输出保真度考察了初始处于纠缠态的两粒子在联合噪声环境中的消纠缠特性。结果表明:两粒子纠缠态可分为相干保持态和脆弱纠缠态,对于脆弱纠缠态分析了它们在低温条件欧姆型耗散下的纠缠消相干演化动力学。 相似文献
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Kondo Resonance versus Fano Interference in Double Quantum Dots Coupled to a Two-Lead One-Ring System 下载免费PDF全文
We analyse the transport properties of a coupled double quantum dot (DQD) device with one of the dots (QD1) coupled to metallic leads and the other (QD2) embedded in an Aharonov-Bhom (A-B) ring by means of the slaveboson mean-field theory. It is found that in this system, the Kondo resonance and the Fano interference exist simultaneously, the enhancing Kondo effect and the increasing hopping of the QD2-Ring destroy the localized electron state in the QD2 for the QD1-leads, and accordingly, the Fano interference between the DQD-leads and the QD1-leads are suppressed. Under some conditions, the Fano interference can be quenched fully and the single Kondo resonance of the QD1-leads comes into being. Moreover, when the magnetic flux of the A-B ring is zero, the influence of the parity of the A-B ring on the transport properties is very weak, but this influence becomes more obvious with non-zero magnetic flux. Thus this model may be a candidate for future device applications. 相似文献
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利用隶玻色子平均场近似理论,并借助于单杂质的Anderson模型的哈密顿量,研究了T型耦合双量子点嵌入正常电极的基态输运性质.结果表明:在体系处于平衡状态时,随着双量子点的耦合强度增加,体系的Kondo 效应被削弱. 当耦合强度足够强时,Kondo量子点态密度的Kondo共振单峰分裂成两个不对等的Kondo共振双峰.在体系处于非平衡状态时,增加两电极的偏压,态密度的Kondo分裂的非对等性明显加强.
关键词:
Kondo效应
态密度
格林函数法
耦合双量子点 相似文献
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Multipartite entanglement in the interaction system between a single-mode microwave cavity field and superconducting charge qubits 下载免费PDF全文
This paper proposes a method of generating multipartite entanglement through using
d.c. superconducting quantum interference devices (SQUID) inside a standing
wave cavity. In this scheme, the d.c. SQUID works in the charge region. It
is shown that, a large number of important multipartite entangled states can
be generated by a controllable interaction between a cavity field and
qubits. It is even possible to produce entangled states involving different
cavity modes based on the measurement of charge qubits states. After such
superpositions states are created, the interaction can be switched off by
the classical magnetic field through the SQUID, and there is no information
transfer between the cavity field and the charge qubits. 相似文献
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Tunable Kondo Effect of a Three-Terminal Transport Quantum Dot Embedded in an Aharonov-Bohm Ring 总被引:1,自引:0,他引:1 下载免费PDF全文
We theoretically investigate the Kondo effect of a three-terminal transport quantum dot (QD) embedded in an Aharonov-Bohm ring in the Kondo regime by means of the one-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We find that in this system, the Kondo effect depends sensitively oil the parity and size of the ring; the Kondo screening cloud can be tuned by tuning the coupling strength of the reservoir-dot. Thus this model might be a candidate for future device applications. 相似文献
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Fano Interference versus Kondo Effect in Strongly Correlated T-Shaped Quantum Dots Embedded in an Aharonov-Bohm Ring 下载免费PDF全文
We theoretically investigate the properties of the ground state of the strongly correlated T-shaped double quantum dots embedded in an Aharonov-Bohm ring in the Kondo regime by means of the one-impurity Anderson Hamiltonian. It is found that in this system, the persistent current depends sensitively on the parity and size of the ring. With the increase of interdot coupling, the persistent current is suppressed due to the enhancing Fano interference weakening the Kondo effect. Moreover, when the spin of quantum dot embedded in the Aharonov- Bohm ring is screened, the persistent current peak is not affected by interdot coupling. Thus this model may be a new candidate for detecting Kondo screening cloud. 相似文献
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Scheme for realizing quantum computation and quantum information transfer with superconducting qubits coupling to a 1D transmission line resonator 下载免费PDF全文
This paper proposes a simple scheme for realizing one-qubit and
two-qubit quantum gates as well as multiqubit entanglement based on
dc-SQUID charge qubits through the control of their coupling to a 1D
transmission line resonator (TLR). The TLR behaves effectively as a
quantum data-bus mode of a harmonic oscillator, which has several
practical advantages including strong coupling strength,
reproducibility, immunity to 1/f noise, and suppressed spontaneous
emission. In this protocol, the data-bus does not need to stay
adiabatically in its ground state, which results in not only fast
quantum operation, but also high-fidelity quantum information
processing. Also, it elaborates the transfer process with the 1D
transmission line. 相似文献