Variational Method Of Pekar Type Research Articles

THE PURE DEPHASING FACTOR OF COULOMB BOUND POLARON IN AN ANISOTROPIC QUANTUM DOT

On the condition of electron–LO-phonon strong coupling in an anisotropic qunntum dot (QD), the eigenenergies of the ground-state and the first excited state, the eigenfunctions of the ground-state and the first excited state are obtained by using a variational method of Pekar type. This system in QD may be employed as a quantum system-qubit. Numerical calculations are performed on the pure dephasing factor. The relations of the pure dephasing factor on the temperature, the Coulomb binding parameter, the electron–LO-phonon coupling strength and the effective confinement length are derived.

Quantum Transition of Two-Level System in a Parabolic Quantum Dot

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.

The decoherence of the two- and three-dimensional parabolic quantum dot qubit

On the condition of electric-LO phonon strong coupling in a two- and three-dimensional parabolic 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 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.

The pure dephasing factor of polaron in an anisotropic quantum dot

On the condition of electron–LO-phonon strong coupling in an anisotropic quantum dot (QD), the eigenenergies and eigenfunctions of the ground-state and the first-excited state are obtained by using a variational method of Pekar type. This system in quantum dot may be employed as a quantum system-qubit. The pure dephasing factor, a measure of the decay of the off-diagonal elements of the density matrix, is studied. Numerical calculations are performed and the relations of the pure dephasing factor on the temperature, the electron–LO-phonon coupling strength and the effective confinement length are derived.

The influence of electric field on a parabolic quantum dot qubit

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.

Properties of Unsymmetrical Parabolic Confinement Potential Quantum Dot Qubit

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.

INFLUENCE OF BOTH ELECTRIC AND MAGNETIC FIELDS ON THE BOUND POLARON IN AN ANISOTROPIC QUANTUM DOT

The binding energy of a bound polaron in an anisotropic quantum dot (QD) subject to electric and magnetic fields along the growth axis has been investigated by using a variational method of Pekar type, taking into account the electron-bulk LO-phonon interaction. The results show that the binding energy decreases with increasing electric field strength and increases with increasing confinement strengths in the lateral and the longitudinal direction, the magnetic field strength, and the Coulomb potential.

Properties of Parabolic Linear Bound Potential and Coulomb Bound Potential Quantum Dot Qubit

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.

The temperature effect of the parabolic linear bound potential quantum dot qubit

On the condition of electric-LO phonon strong coupling in parabolic quantum dot，we obtain the eigenenergy and 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. When the electron is in the superposition state of the ground state and the first-excited state，we obtain the space-time evolution of the electron density. It is shown that the electron density increases with the temperature when the temperature is lower，and the electron density decreases with the temperature when the temperature is higher. At the same time，we found that sometimes the electron density vibrates with the temperature，and its change is slowed down with the strength of coupling increasing.

The effect of Coulomb potential to the decoherence of the parabolic quantum dot qubit

On the condition of electric-LO phonon strong coupling in parabolic quantum dot, we obtained the eigenenergy 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 of quantum dot may be employed as a two-level quantum system-qubit. The phonon spontaneous emission causes the decoherence of the qubit. We discussed the relatoion between the decoherence time and the Coulomb binding parameter，the couping strength, the confinement length, and the conefficient dispersion.

The decoherence of the parabolic linear bound potential quantum dot qubit

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.

Energy levels of strong coupling magnetopolaron in quantum dot

By using variational method of Pekar type, we have studied the energy levels of strong coupling magnetopolaron in disk-shape quantum dot(QD) and quantum well(QW). Our results show that, with the increasing magnetic field and confinement strength, the magnetopolaron binding energy of QD and QW in the ground state and in the excited state is enhanced. The limiting results of bulk type and strict two-dimensional type are obtained.

Size and magnetic field dependence of strong coupling magnetopolaron in quantum dot

By using the variational method of Pekar type, the ground state and the first excited state of the strong coupling magnetopolaron in cylinder-shape quantum dot are considered. The results show that, with the increasing cyclotron frequency and the confinement strength, the magnetopolaron binding energies in both the ground state and the excited state, and the resonance frequency of magnetopolaron are enhanced. The limiting case of the bulk and strict one-dimensional type is also discussed.

Effects of Strong Coupling Magnetopolaron in Quantum Dot

With the use of variational method of Pekar type, we have calculated both the ground state energy and the excited state energy of strong coupling magnetopolaron in disk-shape quantum dot. The dependence of cyclotron resonance frequency of magnetopolaron on the magnetic eld and the confinement strength of quantum dot and quantum well is depicted. The limiting case of bulk type and strict two-dimensional type is discussed.

Strong coupling polaron in quantum well wire

With the use of variational method of Pekar type, we have calculated the polaron binding energies in quantum well wire (QWW) with strong electron-phonon interaction. Our results show that, with the increasing confinement strength of QWW, the polaron binding energy in the ground state and in the excited state increases, further more, the polaron binding energy of symmetric QWW increases faster than that of asymmetric QWW. The limiting case of bulk type, the strict two-dimensional type and the strict one-dimensional type is also discussed.