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1.
Yi-Fu Yu Wei-Ping Li Ji-Wen Yin Jing-Lin Xiao 《International Journal of Theoretical Physics》2011,50(11):3322-3328
On the condition of electric-LO phonon strong coupling in parabolic quantum dot, we obtain the eigenenergies of the ground
state and the first-excited state, the eigenfunctions of the ground state and the first-excited state by using variational
method of Pekar type. This system in quantum dot may be employed as a two-level quantum system-qubit. The phonon spontaneous
emission causes the decoherence of the qubit. We displayed the density matrix of the qubit decayed with the time evolution
and the coherence term of the density matrix element p
10 (or p
01) decayed with the time evolution for different coupling strength, the confinement length, the coefficient dispersion. 相似文献
2.
3.
This paper calculates the time evolution of the quantum mechanical
state of an electron by using variational method of Pekar type on
the condition of electric--LO-phonon strong coupling in a parabolic
quantum dot. It obtains the eigenenergies of the ground state and
the first-excited state, the eigenfunctions of the ground state and
the first-excited state This system in a quantum dot may be employed
as a two-level quantum system qubit. The superposition state
electron density oscillates in the quantum dot with a period when
the electron is in the superposition state of the ground and the
first-excited state. It studies the influence of the electric field
on the eigenenergies of the ground state, the first-excited state
and the period of oscillation at the different electron--LO-phonon
coupling constant and the different confinement length. 相似文献
4.
We study the eigenenergies and eigenfunctions of the
ground and first-excited states of an electron which is
strongly coupled to an LO-phonon in a quantum dot with a triangular
bound potential and Coulomb bound potential by using the Pekar
variational method. This system may be used as a two-level qubit.
Phonon spontaneous emission causes the decoherence of the qubit.
Numerical calculations are performed on the decoherence rate as a
function of the polar angle, the Coulomb binding parameter, the
coupling strength, the confinement length of the quantum dot and the
dispersion coefficient. 相似文献
5.
Wei-Ping Li Ji-Wen Yin Yi-Fu Yu Jing-Lin Xiao Zi-Wu Wang 《International Journal of Theoretical Physics》2009,48(12):3339-3344
The time evolution of the quantum mechanical state of an electron is calculated by using variational method of Pekar type
on the condition of electric-LO phonon strong coupling in a parabolic quantum dot. We obtained the eigen energies of the ground
state and the first-excited state, the eigen functions of the ground state and the first-excited state this system in a quantum
dot may be employed as a two-level quantum system-qubit. The supposition electron is in system’s ground state in the initial
time, the electron transit from the ground state to the excited state in presence of an electric field F along the x axis. The results indicate that the electron transition probability and the oscillation period increase with decreasing the
electron-LO-phonon coupling constant, increasing the electric field and the confinement length. 相似文献
6.
On the condition of electric-LO phonon strong coupling in unsymmetrical
parabolic confinement potential quantum dot (QD),
we obtain the eigenenergies of the ground state
and the first-excited state, the eigenfunctions of the ground
state, and the first-excited state by using variational method of
Pekar type. This system in QD may be employed as a two-level
quantum system-qubit. When the electron is in the superposition
state of the ground state and the first-excited state, we obtain
the time evolution of the electron density. The relations both the
probability density of electron and the period of oscillation with
the electron-LO-phonon coupling strength, the confinement
strengths in the xy-plane and the z-direction are discussed. 相似文献
7.
Based on the variational method of Pekar type, we study the energies and the wave-functions of the ground and the first-excited states of magneto-bipolaron, which is strongly coupled to the LO phonon in a parabolic potential quantum dot under an applied magnetic field, thus built up a quantum dot magneto-bipolaron qubit. The results show that the oscillation period of the probability density of the two electrons in the qubit decreases with increasing electron–phonon coupling strength α, resonant frequency of the magnetic field ω_c, confinement strength of the quantum dot ω_0, and dielectric constant ratio of the medium η; the probability density of the two electrons in the qubit oscillates periodically with increasing time t, angular coordinate φ_2, and dielectric constant ratio of the medium η; the probability of electron appearing near the center of the quantum dot is larger, and the probability of electron appearing away from the center of the quantum dot is much smaller. 相似文献
8.
9.
在量子环中电子与体纵光学声子强耦合的情况下,通过求解能量本征方程,得出了电子的基态和第一激发态的本征能量及其波函数,进而以电子-声子体系的基态与第一激发态构造一个量子比特.结果讨论了消相干时间与耦合强度,色散系数以及量子环内径、外径的变化关系. 相似文献
10.
The Hamiltonian of a quantum rod with an ellipsoidal boundary is given by using a coordinate transformation in which the ellipsoidal boundary is changed into a spherical one.Under the condition of strong electron-longitudinal optical phonon coupling in the rod,we obtain both the electron eigenfunctions and the eigenenergies of the ground and first-excited state by using the Pekar-type variational method.This quantum rod system may be used as a two-level qubit.When the electron is in the superposition state of the ground and first-excited states,the probability density of the electron oscillates in the rod with a certain period.It is found that the oscillation period is an increasing function of the ellipsoid aspect ratio and the transverse and longitudinal effective confinement lengths of the quantum rod,whereas it is a decreasing function of the electron-phonon coupling strength. 相似文献
11.
On the condition of electric-LO phonon strong coupling in a parabolic quantum dot, we obtain the eigenenergy and the eigenfunctions of the ground state and the first-excited state using the variational method of Pekar type. This system in a quantum dot may be employed as a two-level quantum system-qubit. When the electron is in the superposition state of the ground state and the first-excited state, we obtain the time evolution of the electron density. The relations of the probability density of electron on the temperature and the electron-LO-phonon coupling constant and the relations of the period of oscillation on the temperature, the electron-LO-phonon coupling constant, the Coulomb binding parameter and the confinement length are derived. The results show that the probability density of electron oscillates with a period when the electron is in the superposition state of the ground and thefirst-excited state, and show that there are different laws that theprobability density of electron and the period of oscillation change with the temperature and the electron-LO-phonon coupling constant when the temperature is lower or higher. And it is obtained that the period of oscillation decreases with increasing the Coulomb bound potential and increases with increasing the confinement length not only at lower temperatures but also at higher temperatures. 相似文献
12.
Within the frame of the Pavlov–Firsov spin–phonon coupling model, we study the spin-flip assisted by the acoustical phonon scattering between the first-excited state and the ground state in quantum dots. We analyze the behaviors of the spin relaxation rates as a function of an external magnetic field and lateral radius of quantum dot. The different trends of the relaxation rates depending on the magnetic field and lateral radius are obtained, which may serve as a channel to distinguish the relaxation processes and thus control the spin state effectively. 相似文献
13.
We study the eigenenergies and eigenfunctions of the ground and the first-excited states of an electron, which is strongly coupled to LO-phonon in a quantum dot with triangular bound potential by using the Pekar variational method. This system may be used as a two-level qubit. Numerical calculations are performed on the electron probability density varying with respect to the time, the temperature, the electron–LO-phonon coupling strength, the confinement length of the quantum dot and the polar angle. The relationship between the oscillating period and the polar angle is derived. 相似文献
14.
This paper studies the two-electron total energy and the
energy of the electron--electron interaction by using a variational
method of Pekar type on the condition of electric--LO-phonon strong
coupling in a parabolic quantum dot. It considers the following
three cases: 1) two electrons are in the ground state; 2) one
electron is in the ground state, the other is in the first-excited state;
3) two electrons are in the first-excited state. The relations of
the two-electron total energy and the energy of the
electron--electron interaction on the Coulomb binding parameter, the
electron-LO-phonon coupling constant and the confinement length of
the quantum dot are derived in the three cases. 相似文献
15.
Properties of Parabolic Linear Bound Potential and Coulomb Bound Potential Quantum Dot Qubit 总被引:1,自引:0,他引:1
WANG Zi-Wu LI Wei-Ping YIN Ji-Wen XIAO Jing-Lin 《理论物理通讯》2008,49(2):311-314
On the condition of electric-LO phonon strong-coupling in a parabolic quantum dot, we obtain the eigenenergy of the ground-state and the first-excited state, the eigenfunctions of the ground-state and the first-excited state by using variational method of Pekar type. This system in quantum dot may be employed as a two-level quantum system-qubit. When the electron is in the superposition state of the ground- and the first-excited state, we obtain the time evolution of the electron density. The relation of the probability density of electron on the Coulomb binding parameter and the relations of the period of oscillation on the Coulomb binding parameter, the electron-LO-phonon coupling constant and the confinement length are derived. 相似文献
16.
We study the eigenenergies and the eigenfunctions of the ground and the first excited states of an electron, which is strongly coupled to LO-phonon in a quantum rod with a hydrogen-like impurity at the center by using the variational method of Pekar type. This quantum rod system may be used as a two-level quantum qubit. When the electron is in the superposition state of the ground and the first-excited states, the probability density of the electron oscillates in the quantum rod. It is found that the probability density and the oscillation period are individually increased and decreased due to the presence of the Coulomb interaction between the electron and the hydrogen-like impurity. The oscillation period is an increasing function of the ellipsoid aspect ratio and the effective confinement lengths of the quantum rod, whereas it is a decreasing one of the electron–phonon coupling strength. 相似文献
17.
在量子环中电子与体纵光学声子强耦合的情况下,通过求解能量本征方程,得出了电子的基态和第一激发态的本征能量及其波函数,进而以电子-声子系的基态与第一激发态构造了一个量子比特.数值计算结果表明量子比特内电子的空间概率密度分布随时间和空间角坐标作周期性振荡,且振荡周期随耦合强度的增大而减小,说明声子将导致量子比特相干性降低;还表明振荡周期随量子环内径(或外径)的增大而增大,因此适当改变量子环的尺度,可以提高量子比特的相干性.
关键词:
量子环
量子信息
量子比特 相似文献
18.
We investigate coherent time evolution of charge states (pseudospin qubit) in a semiconductor double quantum dot. This fully tunable qubit is manipulated with a high-speed voltage pulse that controls the energy and decoherence of the system. Coherent oscillations of the qubit are observed for several combinations of many-body ground and excited states of the quantum dots. Possible decoherence mechanisms in the present device are also discussed. 相似文献
19.
采用求解能量本征方程、LLP幺正变换、变分相结合的方法研究 球壳量子点中极化子和量子比特的声子效应. 数值计算表明: 声子效应使极化子的基态(或激发态)能量小于电子的基态(或激发态)能量, 使量子比特的振荡周期减小, 且内径给定时, 随着外径的增大声子效应对极化子和量子比特振荡周期的影响越大; 声子效应不改变量子比特内电子概率密度分布的幅值, 量子比特内中心球面处概率密度幅值最大, 界面处概率密度为零, 其它处的概率密度幅值介于最大和最小之间, 且各个空间点的概率密度随半径和方位角的变化而变化, 随时间做周期性振荡. 相似文献
20.
球型量子点量子比特的声子退相干效应 总被引:2,自引:1,他引:1
采用求解能量本征方程、幺正变换及变分相结合的方法,研究声子效应对球型量子点中电子-声子系(极化子)能量、量子比特性质的影响。数值计算表明,能量随量子点尺寸的增大而减小,说明量子点具有明显的量子尺寸效应;当考虑声子效应时,能量、量子比特的振荡周期均减小,说明声子效应使得量子比特的相干性减弱;且量子比特内各空间点的概率密度均随时间做周期性振荡,不同空间点的概率密度随径向坐标和角坐标的变化而变化。 相似文献