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We investigate collision dynamics involving two electrons and a quantum dot embedded in a quantum wire. One electron is initially at rest in the ground state of the dot, whereas the other electron is incident on the dot with a rather well…

Quantum Physics · Physics 2013-03-13 Sølve Selstø

Intermediate spin states that occur in electrostatic dots in the magnetic field regime just beyond the maximum density droplet are investigated. The 5-electron system is studied with exact diagonalization and group theory. The results…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 P. A. Maksym , H. Aoki

We study quantum corrections to conductivity in a 2D system with a smooth random potential and strong spin-orbit splitting of the spectrum. We show that the interference correction is positive and down to the very low temperature can exceed…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Alexander P. Dmitriev , Igor V. Gornyi , Valentin Yu. Kachorovskii

The entanglement of an optically generated electron-hole pair in artificial quantum dot molecules is calculated considering the effects of decoherence by interaction with environment. Since the system evolves into a mixed states and due to…

Mesoscale and Nanoscale Physics · Physics 2016-08-24 H. S. Borges , L. Sanz , A. M. Alcalde

Among the different platforms for quantum information processing, individual electron spins in semiconductor quantum dots stand out for their long coherence times and potential for scalable fabrication. The past years have witnessed…

We study the two-electron eigenspectrum of a carbon-nanotube double quantum dot with spin-orbit coupling. Exact calculation are combined with a simple model to provide an intuitive and accurate description of single-particle and interaction…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 J. von Stecher , B. Wunsch , M. Lukin , E. Demler , A. M. Rey

We briefly review the physics of gate operations between quantum dot spin-qubits and analyze the dynamics of quantum entanglement in such processes. The indistinguishable character of the electrons whose spins realize the qubits gives rise…

Condensed Matter · Physics 2007-05-23 John Schliemann , Daniel Loss

We study a system in which electrons in a two-dimensional electron gas are confined by a nonhomogeneous nuclear spin polarization. The system consists of a heterostructure that has non-zero nuclei spins. We show that in this system…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Yu. V. Pershin

Considering a double-barrier structure formed by a silicon quantum dot covered by natural oxide, we derive simple conditions for the conductance of the dot to become a step-like function of the number of doping atoms inside the dot, with…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 S. V. Vyshenski , U. Zeitler , R. J. Haug

We discuss the possibility to generate, manipulate, and probe single spins in single-level quantum dots coupled to ferromagnetic leads. The spin-polarized currents flowing between dot and leads lead to a non-equilibrium spin accumulation,…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Matthias Braun , Jürgen König , Jan Martinek

The spin states of single electrons in gate-defined quantum dots satisfy crucial requirements for a practical quantum computer. These include extremely long coherence times, high-fidelity quantum operation, and the ability to shuttle…

Semiconductor quantum dots (QDs) offer a platform to explore the physics of quantum electronics including spins. Electron spins in QDs are considered good candidates for quantum bits in quantum information processing, and spin control and…

We study the few-electron eigenspectrum of a nanotube quantum dot with spin-orbit coupling. The two-electron phase diagram as a function of the length of the dot and the applied parallel magnetic field shows clear signatures of both…

Mesoscale and Nanoscale Physics · Physics 2009-06-12 Bernhard Wunsch

We study the spectrum and the transport properties of two identical, vertically coupled quantum dots in a perpendicular magnetic field. We find correlation-induced energy crossings in a magnetic field sweep between states differing only in…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Bernhard Wunsch , David Jacob , Daniela Pfannkuche

We present an analysis of transfer of quantum information between the collective spin degrees of freedom of a large ensemble of two-level systems and a single central qubit. The coupling between the central qubit and the individual ensemble…

Quantum Physics · Physics 2013-05-30 Jonas Refsgaard , Klaus Mølmer

We investigate the dynamics of interacting electrons confined to two types of quantum dot system, when driven by an external AC field. We first consider a system of two electrons confined to a pair of coupled quantum dots by using an…

Mesoscale and Nanoscale Physics · Physics 2018-03-21 C. E. Creffield , G. Platero

Few-electron states in carbon-nanotube quantum dots are studied by means of the configuration-interaction method. The peculiar non-interacting feature of the tunneling spectrum for two electrons, recently measured by Kuemmeth et al. [Nature…

Mesoscale and Nanoscale Physics · Physics 2009-07-18 Andrea Secchi , Massimo Rontani

Electron tunneling through a system formed by two coupled quantum dots in a parallel geometry is considered within a generalized Anderson model. The dots are assumed to have nearly equal radii but different (and tunable) gate voltages. In…

Strongly Correlated Electrons · Physics 2009-11-07 Yshai Avishai , Konstantin Kikoin

Spin-entanglement of two electrons occupying two spatial regions -- domains -- is expressed in a compact form in terms of spin-spin correlation functions. The power of the formalism is demonstrated on several examples ranging from…

Mesoscale and Nanoscale Physics · Physics 2009-04-10 A. Ramsak , J. Mravlje , T. Rejec

Kondo conduction has been observed in a quantum dot with an even number of electrons at the Triplet-Singlet degeneracy point produced by applying a small magnetic field $B$ orthogonal to the dot plane. At a much larger field $ B \sim B_*$,…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 D. Giuliano , B. Jouault , A. Tagliacozzo