THE EFFECT OF ELECTRIC FIELD ON A QUANTUM ROD QUBIT

2012 ◽  
Vol 26 (11) ◽  
pp. 1250068 ◽  
Author(s):  
JING-LIN XIAO
Keyword(s):  
Electric Field ◽  
Probability Density ◽  
Excited States ◽  
Three Dimensional ◽  
Oscillation Period ◽  
Strongly Coupled ◽  
Electron Phonon Coupling ◽  
Rod System ◽  
Quantum Rod ◽  
Electron Probability Density

The Hamiltonian of a quantum rod with an ellipsoidal boundary is given after a coordinate transformation, which changes the ellipsoidal boundary into a spherical one. We study the electron which is strongly coupled to the LO-phonon eigenenergies and eigenfunctions of the ground and the first-excited states in a quantum rod under an applied electric field by using variational method of Pekar type. This quantum rod 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, we obtain the time evolution of the electron probability density. The probability density of the electron oscillates in the quantum rod with an oscillation period. It is found that due to the presence of the three-dimensional anisotropic harmonic potential in the radius and the length directions of the quantum rod, the electron probability density shows double-peak configuration, whereas there is only peak if the confinement is a two-dimensional symmetric one in the x- and y-directions. 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 decreasing one of the electron–phonon coupling strength and the electric field.

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.

Time-dependent electric field effect on the photodetachment dynamics of negative ions

2017 ◽  
Vol 95 (5) ◽  
pp. 507-513 ◽  
Author(s):  
De-hua Wang
Keyword(s):  
Electric Field ◽  
Probability Density ◽  
External Electric Field ◽  
Negative Ions ◽  
Time Dependent ◽  
Negative Ion ◽  
Electric Field Effect ◽  
Electron Trajectories ◽  
Oscillatory Pattern ◽  
Electron Probability Density

This paper addresses the photodetachment dynamics of a negative ion in a time-dependent electric field based on the semiclassical open-orbit theory. The photodetached electron probability density in a real time domain is studied in a gradient electric field for the first time. It is found that because of the influence of the gradient electric field, two or more electron trajectories can arrive at a given point on the detector, and the interference effect between these electron trajectories causes oscillatory structures in the electron probability density. Our calculation results suggest that when the external electric field changes very slowly with time, only two electron trajectories can arrive at a given point on the detector and the electron probability density exhibits a regular two-term oscillatory pattern. However, when the electric field changes quickly with time, four electron trajectories can reach the detector, which makes the oscillatory structures in the electron probability density become much more complicated. In addition, the electric field strength, photon energy, and the position of the detector can affect the electron probability density of this system sensitively. Our study provides a clear and intuitive picture for the photodetachment dynamics of the negative ion in the external electric field from a time-dependent viewpoint and may guide the future experimental researches on the photodetachment microscopy of negative ions in the time-dependent electric field.

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.

The Effect of Roughness Features on Mos Surface Electric Field and Fowler-Nordheim Tunneling Behavior

1997 ◽  
Vol 473 ◽  
Author(s):  
Heng-Chih Lin ◽  
Edwin C. Kan ◽  
Toshiaki Yamanaka ◽  
Simon J. Fang ◽  
Kwame N. Eason ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Interface Roughness ◽  
Normal Electric Field ◽  
Surface Electric Field ◽  
Tunneling Behavior ◽  
Nordheim Tunneling

ABSTRACTFor future CMOS GSI technology, Si/SiO2 interface micro-roughness becomes a non-negligible problem. Interface roughness causes fluctuations of the surface normal electric field, which, in turn, change the gate oxide Fowler-Nordheim tunneling behavior. In this research, we used a simple two-spheres model and a three-dimensional Laplace solver to simulate the electric field and the tunneling current in the oxide region. Our results show that both quantities are strong functions of roughness spatial wavelength, associated amplitude, and oxide thickness. We found that RMS roughness itself cannot fully characterize surface roughness and that roughness has a larger effect for thicker oxide in terms of surface electric field and tunneling behavior.

scholarly journals Simulation of Thermal and Electric Field Distribution in Packaged Sausages Heated in a Stationary Versus a Rotating Microwave Oven

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1622
Author(s):  
Wipawee Tepnatim ◽  
Witchuda Daud ◽  
Pitiya Kamonpatana
Keyword(s):  
Temperature Distribution ◽  
Electric Field ◽  
Three Dimensional ◽  
Development Stage ◽  
Microwave Oven ◽  
Computational Time ◽  
Plastic Package ◽  
Heating Uniformity ◽  
The Cost ◽  
Good Agreement

The microwave oven has become a standard appliance to reheat or cook meals in households and convenience stores. However, the main problem of microwave heating is the non-uniform temperature distribution, which may affect food quality and health safety. A three-dimensional mathematical model was developed to simulate the temperature distribution of four ready-to-eat sausages in a plastic package in a stationary versus a rotating microwave oven, and the model was validated experimentally. COMSOL software was applied to predict sausage temperatures at different orientations for the stationary microwave model, whereas COMSOL and COMSOL in combination with MATLAB software were used for a rotating microwave model. A sausage orientation at 135° with the waveguide was similar to that using the rotating microwave model regarding uniform thermal and electric field distributions. Both rotating models provided good agreement between the predicted and actual values and had greater precision than the stationary model. In addition, the computational time using COMSOL in combination with MATLAB was reduced by 60% compared to COMSOL alone. Consequently, the models could assist food producers and associations in designing packaging materials to prevent leakage of the packaging compound, developing new products and applications to improve product heating uniformity, and reducing the cost and time of the research and development stage.

scholarly journals Prandtl Number in Classical Hard-Sphere and One-Component Plasma Fluids

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 821
Author(s):  
Sergey Khrapak ◽  
Alexey Khrapak
Keyword(s):  
Prandtl Number ◽  
Hard Sphere ◽  
Solid Phase ◽  
Freezing Point ◽  
Three Dimensional ◽  
Order Unity ◽  
Strongly Coupled ◽  
Dielectric Fluids ◽  
Weakly Coupled ◽  
Component Plasma

The Prandtl number is evaluated for the three-dimensional hard-sphere and one-component plasma fluids, from the dilute weakly coupled regime up to a dense strongly coupled regime near the fluid-solid phase transition. In both cases, numerical values of order unity are obtained. The Prandtl number increases on approaching the freezing point, where it reaches a quasi-universal value for simple dielectric fluids of about ≃1.7. Relations to two-dimensional fluids are briefly discussed.

scholarly journals Three-dimensional 𝒩 = 2 supersymmetric gauge theories and partition functions on Seifert manifolds: A review

2019 ◽  
Vol 34 (23) ◽  
pp. 1930011 ◽  
Author(s):  
Cyril Closset ◽  
Heeyeon Kim
Keyword(s):  
Correlation Functions ◽  
Gauge Theories ◽  
Three Dimensional ◽  
Partition Functions ◽  
Exact Results ◽  
Strongly Coupled ◽  
Seifert Manifolds ◽  
Recent Developments ◽  
Supersymmetric Gauge ◽  
Chern Simons

We give a pedagogical introduction to the study of supersymmetric partition functions of 3D [Formula: see text] supersymmetric Chern–Simons-matter theories (with an [Formula: see text]-symmetry) on half-BPS closed three-manifolds — including [Formula: see text], [Formula: see text], and any Seifert three-manifold. Three-dimensional gauge theories can flow to nontrivial fixed points in the infrared. In the presence of 3D [Formula: see text] supersymmetry, many exact results are known about the strongly-coupled infrared, due in good part to powerful localization techniques. We review some of these techniques and emphasize some more recent developments, which provide a simple and comprehensive formalism for the exact computation of half-BPS observables on closed three-manifolds (partition functions and correlation functions of line operators). Along the way, we also review simple examples of 3D infrared dualities. The computation of supersymmetric partition functions provides exceedingly precise tests of these dualities.

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