Comparison of bound magneto-polaron in circular, elliptical, and triangular quantum dot qubit
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Comparison of bound magneto‑polaron in circular, elliptical, and triangular quantum dot qubit R. Khordad1 · H. R. Rastegar Sedehi2 Received: 9 February 2020 / Accepted: 31 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract In the present work, we consider an electron which is strongly coupled to the LO-phonon in circular, elliptical, and triangular quantum dots with Coulomb impurity. The eigenenergies and eigenfunctions of the ground and the first-excited states of the electron are obtained under magnetic and electric fields by using the Pekar variational method. We have also obtained the Shannon entropy and the electron probability density. This system can be applied as a two-level qubit. The entropy shows the oscillatory periodic evolution as function of the time due to the form of the confinement. It is seen that entropy has an arrangement periodic behavior for the higher symmetry (circular quantum dot). Keywords Quantum dot · Pekar variational method · Polaron
1 Introduction Over the past two decades, a considerable attention has been devoted to quantum dots (QDs) due to their novel properties and the potential applications in information science field (Fedichkin and Fedorov 2004). One of the most important applications of QDs is quantum computing application (Li et al. 2010; Nielsen and Chang 2000; Yu et al. 2011). Quantum computing as a fast growing research field employs computer science with quantum mechanics (Wen et al. 2009; Hawrylak and Korkusinski 2005; Bennett and DiVincenzo 2000). In quantum computing science, the construction and manipulation of a qubit in nanostructures are two important subjects. Hitherto, many efforts have been performed for realizing quantum computation by several schemes (Makhlin et al. 1999; Gershenfeld and Chuang 1997; Loss and DiVincenzo 1998). Since the quantum dots have an analogy with artificial atomic systems, the QD systems can provide excellent grounds for testing quantum mechanics. The QDs can be fabricated in different shapes and sizes. QDs with the novel physical effects can be applied in microelectronic devices. For this purpose, several authors have considered quantum dots with various confinement potential. The prediction of confinement * R. Khordad [email protected] 1
Department of Physics, College of Sciences, Yasouj University, Yasouj 75918‑74934, Iran
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Department of Physics, Jahrom University, P. O. Box 74137‑66171 Jahrom, Iran
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potential profile in QDs plays an important role in physics of nanostructures (Rajamohan et al. 2008; Johnson 1995; Kwasniowski and Adamowski 2008; Bednarek et al. 1999; Szafran et al. 1999). It is to be noted that the knowledge of the realistic profile of the confinement potentials is important in theoretical studies of the electronic properties of QDs. Confinement potentials that confine charge carriers in QDs have various shapes depending on their origin and the structure of the QD (Zhu et al. 1994;
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