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1.
LIU Jian-Xin YAN Zhan-Yuan 《理论物理通讯》2005,44(6):1091-1094
The research work on the quantum effects in mesoscopic circuits has undergone a rapid development recently, however the whole quantum theory of the mesoscopic circuits should consider the discreteness of the electric charge. In this paper, based on the fundamental fact that the electric charge takes discrete values, the finite-difference Schrodinger equation of the mesoscopic RLC circuit with a source is achieved. With a unitary transformation, the Schrodinger equation becomes the standard Mathieu equation, then the energy spectrum and the wave functions of the system are obtained. Using the WKBJ method, the average of durrents and square of the current are calculated. The results show the existence of the current fluctuation, which causes noise in the circuits. This paper is an application of the whole quantum mesoscopic circuits theory to the fundamental circuits, and the results will shed light on the design of the miniation circuits, especially on the purpose of reducing quantum noise coherent controlling of the mesoscopic quantum states. 相似文献
2.
Using the quantum theory for a
mesoscopic circuit based on the discretenes of electric charges,
the finite-difference Schrödinger equation of the non-dissipative mesoscopic inductance and capacity coupling circuit is achieved. The Coulomb blockade effect, which is caused
by the discreteness of electric charges, is studied. Appropriately
choose the components in the circuits, the finite-difference
Schrödinger equation can be divided into two Mathieu
equations in \hat p representation. With the WKBJ method, the
currents quantum fluctuations in the ground states of the two
circuits are calculated. The results show that the currents
quantum zero-point fluctuations of the two circuits are exist and
correlated. 相似文献
3.
YAN Zhan-Yuan ZHANG Xiao-Hong HAN Ying-Hui 《理论物理通讯》2008,50(8):521-524
The open electron resonator is a mesoscopic device that has attracted considerable attention due to its remarkable behavior: conductance oscillations. In this paper, using an improved quantum theory to mesoscopic circuits developed recently by Li and Chen, the mesoscopic electron resonator is quantized based on the fundamental fact that the electric charge takes discrete value. With presentation transformation and unitary transformation, the SchrSdinger equation becomes an standard Mathieu equation. Then, the detailed energy spectrum and wave functions in the system axe obtained, which will be helpful to the observation of other characters of electron resonator. The average of currents and square of the current are calculated, the results show the existence of the current fluctuation, which causes the noise in the circuits, the influence of inductance to the noise is discussed. With the results achieved, the stability characters of mesoscopic electron resonator are studied firstly, these works would be benefit to the design and control of integrate circuit. 相似文献
4.
Using the path integral method we derive quantum wave function and quantum fluctuations of charge andcurrent in the mesoscopic RLC circuit. We find that the quantum fluctuation of charge decreases with time, oppositely,the quantum fluctuation of current increases with time monotonously. Therefore there is a squeezing effect in the circuit.If some more charge devices are used in the mesoscopic-damped circuit, the quantum noise can be reduced. We also findthat uncertainty relation of charge and current periodically varies with the period π/2 in the under-damped case. 相似文献
5.
By means of the thermal field dynamics theory invented by Takahashi and Umezawa, we study the quantum effects of a nondissipative mesoscopic RLC circuit at a finite temperature. 相似文献
6.
The mesoscopic nonlinear inductance-capacitance circuit is a typical anharmonie oscillator, due to diodes included in the circuit. In this paper, using the advanced quantum theory of mesoseopie circuits, which based on the fundamental fact that the electric charge takes discrete value, the diode included mesoscopic circuit is firstly studied. Schrodinger equation of the system is a four-order difference equation in p rep asentation. Using the extended perturbative method, the detail energy spectrum and wave functions axe obtained and verified, as an application of the results, the current quantum fluctuation in the ground state is calculated. Diode is a basis component in a circuit, its quantization would popularize the quantum theory of mesoscopie circuits. The methods to solve the high order difference equation are helpful to the application of mesoscopic quantum theory. 相似文献
7.
Quantum Mechanical Effects in a Non-Dissipation Mesoscopic Coupled Circuit in the Presence of Source
Under the squeezed vacuum state, the quantum zero point fluctuations for both the charge and current of a non-dissipation mesoscopic coupled circuit in the presence of source are given. The quantum mechanical effects of this circuit at zero temperature are studied. 相似文献
8.
The mesoscopic nonlinearinductance-capacitance circuit is a typical anharmonicoscillator, due to diodes included in the circuit. In this paper, using the advanced quantum theory of mesoscopic circuits, which based on the fundamental fact that the electric charge takes discrete value, the diode included mesoscopic circuit is firstly studied. Schrödinger equation of the system is a four-order difference equation in \hat{p} representation.Using the extended perturbative method, the detail energy spectrumand wave functions are obtained and verified, as an application ofthe results, the current quantum fluctuation in the ground state iscalculated. Diode is a basis component in a circuit, its quantization would popularize the quantum theory of mesoscopic circuits. The methods to solve the high order difference equation are helpful to the application of mesoscopic quantum theory. 相似文献
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11.
WAN Hua-Ming LUO Hai-Mei WANG Yi-Fan 《理论物理通讯》2005,44(12)
Based on the maximum entropy principle, we present a density matrix of mesoscopic RLC circuit to make it possible to analyze the connection of the initial condition with temperature. Our results show that the quantum state evolution is closely related to the initial condition, and that the system evolves to generalized coherent state if it is in ground state initially, and evolves to squeezed state if it is in excited state initially. 相似文献
12.
WAN Hua-Ming LUO Hai-Mei WANG Yi-Fan 《理论物理通讯》2005,44(6):1045-1049
Based on the maximum entropy principle, we present a density matrix of mesoscopic RLC circuit to make it possible to analyze the connection of the initial condition with temperature. Our results show that the quantum state evolution is closely related to the initial condition, and that the system evolves to generalized coherent state if it is in ground state initially, and evolves to squeezed state if it is in excited state initially. 相似文献
13.
Bin Chen Xiaojuan Shen LiLy Sun Rushan Han 《International Journal of Theoretical Physics》2007,46(2):199-205
The quantum theory for mesoscopic electric circuit with charge discreteness is briefly described. The Schrödinger equation of the mesoscopic electric circuit with external source which is the time function has been proposed. By using the instanton methods, the macroscopic quantum coherent phenomena and effective capacitance oscillation in the mesoscopic electric circuit have been addressed. 相似文献
14.
Xing-Lei Xu Hong-Qi Li Ji-Suo Wang 《International Journal of Theoretical Physics》2006,45(12):2471-2482
Mesoscopic damped double resonance mutual capacitance coupled RLC circuit is quantized by the method of damped harmonic oscillator quantization. The Hamiltonian is diagonalized by unitary transformation. The eigenenergy spectra of this circuit are given. The quantum fluctuations of the charges and current of each loop are researched in excitation state of the squeezed vacuum state, the squeezed vacuum state and in vacuum state. It is show that, the quantum fluctuations of the charges and current are related to not only circuit inherent parameter and coupled magnitude, but also quantum number of excitation, squeezed coefficients, squeezed angle and damped resistance. And, because of damped resistance, the quantum fluctuation decay along with time.
PACS numbers: 03.65.-w,42.50.Lc. 相似文献
15.
We present a density matrix of a mesoscopic RLC circuits to make it possible to analyze the connection between the initial
condition and the certain temperature. Our results show that the quantum state evolution will be closely related to the initial
condition; the system evolves to generalized coherent state if it is in ground state initially, and evolves to squeezed state
if it is in excited state initially. In addition, we also obtain squeezed minimum uncertainty state with satisfying certain
condition in mesoscopic RLC circuit. 相似文献
16.
17.
YU You-Hong 《理论物理通讯》2008,49(4):1052-1054
The invariants for a mesoscopic RLC circuit with a
power source are studied and used to construct the squeezed states
and squeezed number states for the system. The quantum
fluctuations of the mesoscopic RLC circuit in the
squeezed states and squeezed number states are also investigated. 相似文献
18.
We study the quantum fluctuations of the charge and current of two L-C dissipative mcsoscopic circuit withthe mutual inductance in the vacuum state. Our results show that the system state will evolve to a squerzcd coherentstate under the effect of external source. We find that the squeezing amplitude parameter is relative to the parametersof circuit and the mutual-inductance coefficient in the existence of dissipation. Whcn the circuit has no dissipation orthere is complete coupling between two meshes, the squeezing amplitude parameter only depends on the capacitance'sratio. 相似文献
19.
介观RLC并联电路量子效应 总被引:1,自引:0,他引:1
研究了介观RLC并联电路系统量子态随时间的演化,结果表明,在外加电源作用下,有耗散的RLC并联电路,系统将由初始的真空态演化到压缩态。 相似文献
20.
Ji Ying-Hua Wan Xiang-Dong Hu Yin-Quan Lei Min-Sheng 《International Journal of Theoretical Physics》2003,42(8):1765-1771
The quantum theory of the mesoscopic RLC circuit and the condition for Coulomb blockade are given by using canonical quantization and a unitary transformation from the classical equation of motion. Our results show that there is a threshold voltage T in the circuit. The threshold voltage is related not only to the junction capacitance and inductance, but also to the resistance of the circuit. Generally speaking, the larger the resistance, the larger the threshold voltage. This clarifies the phenomenon of the Coulomb blockade of the dissipative mesoscopic circuit. 相似文献