DECOHERENCE OF THE TRIANGULAR BOUND POTENTIAL QUANTUM DOT QUBIT

2009 ◽  
Vol 23 (27) ◽  
pp. 3273-3279 ◽  
Author(s):  
JIA-KUI SUN ◽  
HONG-JUAN LI ◽  
JING-LIN XIAO
Keyword(s):  
Quantum Dot ◽  
Variational Method ◽  
Excited States ◽  
Polar Angle ◽  
Numerical Results ◽  
Coupling Constant ◽  
Phonon Coupling ◽  
Strongly Coupled ◽  
Decoherence Rate ◽  
Triangular Bound Potential

We study the eigenenergies and the eigenfunctions of the ground and the first excited states of an electron, which is strongly coupled to the 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. Our numerical results indicate that the decoherence rate will decrease with increasing the confinement length of the quantum dot (QD) and decrease with increasing electron-LO-phonon coupling constant. The influences of the polar angle on the decoherence rate are dominant when the coupling constant increases, while the effects of the polar angle on that are strong when the confinement length increases. Meanwhile, the decoherence rate varies periodically with respect to the polar angle.

OPTICAL PHONON EFFECT IN AN ASYMMETRIC QUANTUM DOT QUBIT

2012 ◽  
Vol 10 (07) ◽  
pp. 1250077 ◽  
Author(s):  
ZHAO-HUA DING ◽  
YONG SUN ◽  
JING-LIN XIAO
Keyword(s):  
Quantum Dot ◽  
Excited States ◽  
Oscillation Period ◽  
Present System ◽  
Superposition State ◽  
Strongly Coupled ◽  
Asymmetric Quantum Dot ◽  
Asymmetric Quantum ◽  
Electron Phonon Coupling ◽  
Increasing Function

We investigate the eigenenergies and the eigenfunctions of the ground and the first excited states of an electron, which is strongly coupled to LO-phonon in an asymmetric quantum dot (QD) by using variational method of Pekar type. The present system may be used as a two-level 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 QD with a certain period. It is found that the oscillation period is an increasing function of the transverse and the longitudinal effective confinement lengths of the QD, whereas it is a decreasing one of the electron–phonon coupling strength.

TEMPERATURE-DEPENDENCE OF STRONG-COUPLED BOUND POLARON IN A TRIANGULAR POTENTIAL QUANTUM DOT

2012 ◽  
Vol 26 (03) ◽  
pp. 1150015 ◽  
Author(s):  
ZHI-XIN LI
Keyword(s):  
High Temperature ◽  
Quantum Dot ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Polar Angle ◽  
Strongly Coupled ◽  
Influence Of Temperature ◽  
Leading Role ◽  
Bound Polaron

We study the temperature effect of bound polaron, which is strongly coupled to LO-phonon by using a variational method of the Pekar type in a triangular potential quantum dot (QD). The ground state energy was expressed as functions of the confinement length of QD, the Coulomb bound potential, the polar angle and the temperature. It is found that at low temperature, the influence of Coulomb bound potential and the confinement length of QD to the ground state energy of bound polaron play a leading role. At high temperature, the influence of temperature to the ground state energy of bound polaron is dominant.

POLARON CORRECTION TO THE NEGATIVE DONOR ON THE HETERO-INTERFACE IN MAGNETIC FIELDS (II–VI CRYSTALS)

2003 ◽  
Vol 17 (31n32) ◽  
pp. 6097-6107 ◽  
Author(s):  
XIAOYAN ZHANG ◽  
XU WANG ◽  
GUOLIANG FAN
Keyword(s):  
Magnetic Fields ◽  
Variational Method ◽  
Triplet State ◽  
Numerical Results ◽  
Binding Energies ◽  
Phonon Coupling ◽  
Polar Crystal ◽  
Spin Triplet

Negative donor ion on the hetero-interface in magnetic fields are investigated. Using a variational method, we have calculated the binding energies of D- center for the spin-triplet state of L=-1 in this structure. Moreover, the effect of electron-interface phonon coupling on the energy of a donor located in a polar-crystal hetero-interface is found. Numerical results are produced for heterostructures of some II–VI crystals.

Ground and Excited States of the Two and Three Dimensional Bipolaron in a Quantum Dot

2007 ◽  
Vol 546-549 ◽  
pp. 1945-1950
Author(s):  
Yong Hong Ruan ◽  
Guo Wei Pan ◽  
Qing Hu Chen
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Excited States ◽  
Lower Energy ◽  
Three Dimensional ◽  
Coupling Constants ◽  
Phonon Coupling ◽  
Excitation Energies ◽  
Electron Phonon Coupling ◽  
Franck Condon

We apply the Lee-Low-Pines-Huybrechts variational method to study the properties of the two and three dimensional bipolaron in a quantum dot. The ground-state (GS) and two types of excited-state energies of the Fröhlich bipolaron for the whole range of electron-phonon coupling constants can be obtained. Compared with the Franck-Condon excited state, the first relaxed excited state has a lower energy. Effects of quantum dot confinement on the excitation energies of the bipolaron are given.

MAGNETOPOLARON IN A CYLINDRICAL QUANTUM DOT

2009 ◽  
Vol 08 (04n05) ◽  
pp. 455-463 ◽  
Author(s):  
M. TCHOFFO ◽  
L. C. FAI ◽  
N. ISSOFA ◽  
S. C. KENFACK ◽  
J. T. DIFFO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Dot ◽  
Longitudinal Direction ◽  
Logarithmic Function ◽  
Magnetic Field Effects ◽  
Coupling Constant ◽  
Phonon Coupling ◽  
Cyclotron Radius ◽  
Effective Electron ◽  
Electron Phonon Coupling

We examine the magnetopolaron state in a cylindrical quantum dot with a transverse parabolic potential and a high rectangular potential well in the longitudinal direction. The quadratic dependence of the magnetopolaron energy versus Fröhlich electron–phonon coupling constant for different cyclotron radii and constant structure radius is modulated by a logarithmic function seems to depend on the Fröhlich coupling constant. The same law is seen in the case of magnetopolaron energy versus Fröhlich electron–phonon coupling constant for different structure radii and constant cyclotron radius. The energies are seen to be lifted in different fashions in the case of the structure and cyclotron radii. The high degrees of confinement (or high magnetic field) lead to an enhancement in the effective electron–phonon coupling that in turn brings about the possibility that in spite of weak polar coupling as in GaAS say, the polaron problem may also have strong-coupling counterparts arising from confinement or magnetic field effects. The polaron mass increases with increasing Fröhlich electron–phonon coupling constant. The dependence seems to be fourth-order law of the Fröhlich coupling constant modulated by a logarithmic function.

scholarly journals Estimation of electron-phonon coupling constant in Ba1-xKxBiO3

2020 ◽  
Vol 1686 ◽  
pp. 012049
Author(s):  
Alexander E Lukyanov ◽  
Vyacheslav D Neverov ◽  
Andrey V Krasavin ◽  
Alexey P Menushenkov
Keyword(s):  
Coupling Constant ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

scholarly journals Entangled Photon Pairs Produced by a Quantum Dot Strongly Coupled to a Microcavity

2008 ◽  
Vol 100 (24) ◽  
Author(s):  
R. Johne ◽  
N. A Gippius ◽  
G. Pavlovic ◽  
D. D. Solnyshkov ◽  
I. A. Shelykh ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Strongly Coupled ◽  
Photon Pairs ◽  
Entangled Photon Pairs

VIBRATIONAL FREQUENCY OF IMPURITY BOUND MAGNETOPOLARON IN AN ANISOTROPIC QUANTUM DOT

2009 ◽  
Vol 23 (20n21) ◽  
pp. 2449-2456 ◽  
Author(s):  
WEI XIAO ◽  
JING-LIN XIAO
Keyword(s):  
Quantum Dot ◽  
Interaction Energy ◽  
Coupling Strength ◽  
Vibrational Frequency ◽  
Cyclotron Frequency ◽  
Operator Method ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Anisotropic Quantum Dot ◽  
Bound Magnetopolaron

We study the vibrational frequency and the interaction energy of the weak-coupling impurity bound magnetopolaron in an anisotropic quantum dot. The effects of the transverse and longitudinal effective confinement lengths, the electron–phonon coupling strength, the cyclotron frequency of a magnetic field and the Coulomb bound potential are taken into consideration by using an improved linear combination operator method. It is found that the vibrational frequency and the interaction energy will increase rapidly with decreasing confinement lengths and increasing the cyclotron frequency. The vibrational frequency is an increasing function of the Coulomb bound potential, whereas the interaction energy is an decreasing one of the potential and the electron–phonon coupling strength.

Sign in / Sign up

Export Citation Format

Share Document