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1.
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
2.
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
3.
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
4.
The Hamiltonian of a quantum rod with an ellipsoidal boundary is given after a coordinate transformation that changes the ellipsoidal boundary into a spherical one. The properties of the quantum rods constituting the bridge between two-dimensional quantum wells, zero-dimensional quantum dots and one-dimensional quantum wires are explored theoretically using linear combination operator method. The first internal excited state energy, the excitation energy and the transition frequency between the first internal excited and the ground states of the strong-coupled impurity-bound polaron in the rod with Coulomb-bound potential, the transverse effective confinement length, the ellipsoid aspect ratio and the electron–phonon coupling strength are studied. It is found that the first internal excited state energy, the excitation energy and the transition frequency are increasing functions of the Coulomb-bound potential and the electron–phonon coupling strength, whereas they are decreasing functions of the ellipsoid aspect ratio and the transverse effective confinement length. These results can be attributed to the interesting quantum size confining effects. 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.
The Hamiltonian of a quantum rod with an ellipsoidal boundary is given after a coordinate transformation that changes the ellipsoidal boundary into a spherical one. We then study the vibrational frequency and the ground state binding energy of the strong-coupling magnetopolaron in a quantum rod. The effects of the electron–phonon coupling strength, the cyclotron frequency of a magnetic field, the aspect ratio of the ellipsoid and the transverse and longitudinal effective confinement lengths are taken into consideration by using the linear combination operator method. It is found that the vibrational frequency and the ground state binding energy are increasing functions of the electron–phonon coupling strength and the magnetic field cyclotron frequency, whereas they are decreasing functions of the aspect ratio of the ellipsoid and effective confinement lengths. 相似文献
7.
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
8.
Vibrational frequency of a strong-coupling polaron in a quantum rod at finite temperatures 下载免费PDF全文
The Hamiltonian of a quantum rod with a boundary is presented after a coordinate transformation that changes the original ellipsoidal boundary into a spherical one. We then study the effect of temperature on the vibrational frequency and the ground state binding energy of the strong-coupling polaron in the rod. The two quantities are expressed as functions of the aspect ratio of the ellipsoid, the transverse and the longitudinal effective confinement lengths, the temperature and the electron—phonon coupling strength by linear combination operator and unitary transformation methods. It is found that the vibrational frequency and the ground state binding energy will increase rapidly with decreasing transverse and longitudinal effective confinement lengths. They are increasing functions of the electron—phonon coupling strength but become decreasing ones of the temperature and the aspect ratio. 相似文献
9.
10.
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
11.
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
12.
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
13.
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 eigenfuctions 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. The relations between the decoherence time with the coupling strength, the confinement length, the coefficient dispersion are discussed. 相似文献
14.
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
15.
量子棒中强耦合杂质束缚极化子的振动频率 总被引:1,自引:0,他引:1
给出了具有椭球边界量子棒经坐标变换成球形边界的哈密顿量。采用线性组合算符和幺正变换的方法研究了在非均匀抛物限制势下量子棒中强耦合杂质束缚极化子的性质。导出了量子棒中强耦合杂质束缚极化子的振动频率和声子平均数随库仑束缚势、电子-声子耦合强度、椭球的纵横比和量子棒的横向和纵向有效受限长度的变化关系。数值计算结果表明:振动频率和声子平均数随电子-声子耦合强度和库仑束缚势的增强而增加,随量子棒的横向和纵向有效受限长度和椭球的纵横比的减小而增大。表现出量子棒的奇特的量子尺寸限制效应。 相似文献
16.
Jing-Lin Xiao 《Chinese Journal of Physics (Taipei)》2017,55(1):22-27
We change the ellipsoidal boundary in a quantum rod (QR) into a spherical one by a coordinate transformation, and then study the influences of the ellipsoid aspect ratio and polaron radius on the probability density (PD) and oscillation period (OP) of an electron with the variational method of Pekar type (VMPT). By employing the quantum statistics theory (QST), we investigate the temperature effects on the PD and the OP. Numerical results denote that the electron probability density and the oscillation period increase (decay) with raising temperature in lower (higher) temperature regime. The electron probability density increases (decreases) with increasing ellipsoid aspect ratio when the temperature is in lower (higher) regime. The electron probability density decays (enhances) with increasing polaron radius when the temperature is in lower (higher) temperature regime. The oscillation period is an increasing function of the ellipsoid aspect ratio, whereas it is a decreasing one of the polaron radius. 相似文献
17.
给出了具有椭球边界量子棒经过坐标变换成球形边界的哈密顿量.采用线性组合算符和幺正变换的方法研究了在抛物限制势下量子棒中弱耦合磁极化子的振动频率和基态结合能随横向和纵向有效受限长度、电子-声子耦合强度、椭球的纵横比以及磁场的回旋频率的变化关系.数值计算结果表明:振动频率和基态结合能随回旋频率的增加而增大,随横向和纵向有效受限长度的减少而迅速增大.基态结合能随耦合强度的增加而增大.振动频率随纵横比的增加而减少.当e′1时,基态结合能随纵横比的增加而增加.e′1时,随着纵横比的减少,基态结合能增大.当e′=1时,基态结合能取稳定的极小值. 相似文献
18.
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
19.
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
20.
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