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An important requirement for a physical embodiment of a quantum computer is that arbitrary single-qubit operations can be performed. In the case of spin-qubits, this means that arbitrary spin rotations must be possible. Here we demonstrate…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. M. Tyryshkin , S. A. Lyon , W. Jantsch , F. Schaeffler

Time-resolved Kerr rotation measurements were performed in InGaAs/GaAs quantum wells nearby a doped Mn delta layer. Our magneto-optical results show a typical time evolution of the optically-oriented electron spin in the quantum well.…

Electron spin coherence has been generated optically in n-type modulation doped (In,Ga)As/GaAs quantum dots (QDs) which contain on average a single electron per dot. The coherence arises from resonant excitation of the QDs by…

We study the spin and charge dynamics of electrons in n-doped II--VI semiconductor multiple quantum wells when one or more quantum wells are doped with Mn. The interplay between strongly nonlinear inter-well charge transport and the large…

Condensed Matter · Physics 2009-11-07 Manuel Bejar , David Sanchez , Gloria Platero , A. H. MacDonald

Conduction electron spin lifetimes ($T_1$) and spin coherence times ($T_2$) are strongly modified in semiconductor quantum wells by electric fields. Quantitative calculations in GaAs/AlGaAs quantum wells at room temperature show roughly a…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 Wayne H. Lau , Michael E. Flatté

The spin dynamics of an interwell excitons gas has been investigated in n-i-n GaAs/AlGaAs coupled quantum wells (CQWs). In these heterostructures the electron and the hole are spatially separated in neighboring quantum wells by a narrow…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 A. V. Larionov , V. E. Bisti , M. Bayer , J. Hvam , K. Soerensen

Full insight into the dynamics of a coupled quantum system depends on the ability to follow the effect of a local excitation in real-time. Here, we trace the coherent evolution of a pair of coupled atomic spins by means of scanning…

We develop a microscopic theory of spin relaxation of a two-dimensional electron gas in quantum wells with anisotropic electron scattering. Both precessional and collision-dominated regimes of spin dynamics are studied. It is shown that, in…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 A. V. Poshakinskiy , S. A. Tarasenko

Spin manipulation in coupled quantum dots is of interest for quantum information applications. Control of the exchange interaction between electrons and holes via an applied electric field may provide a promising technique for such spin…

We demonstrate that the superposition of light polarization states is coherently transferred to electron spins in a semiconductor quantum well. By using time-resolved Kerr rotation we observe the initial phase of Larmor precession of…

We theoretically describe the spin excitation spectrum of a two dimensional electron gas embedded in a quantum well with localized magnetic impurities. Compared to the previous work, we introduce equations that allow to consider the…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Florent Perez , Joel Cibert , Masha Vladimirova , Denis Scalbert

Electron transport properties in a parallel double-quantum-dot structure with three-terminals are theoretically studied. By introducing a local Rashba spin-orbit coupling, we find that an incident electron from one terminal can select a…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Weijiang Gong , Yisong Zheng

We theoretically analyze the dynamics of an atomic double-well system with a single ion trapped in its center. We find that the atomic tunnelling rate between the wells depends both on the spin of the ion via the short-range spin-dependent…

Quantum Physics · Physics 2015-06-19 Jannis Joger , Antonio Negretti , Rene Gerritsma

Larmor's theorem holds for magnetic systems that are invariant under spin rotation. In the presence of spin-orbit coupling this invariance is lost and Larmor's theorem is broken: for systems of interacting electrons, this gives rise to a…

Mesoscale and Nanoscale Physics · Physics 2017-07-12 Shahrzad Karimi , Florent Baboux , Florent Perez , Carsten A. Ullrich , Grzegorz Karczewski , Tomasz Wojtowicz

Electron spins in a semiconductor quantum well couple to an electric field {\it via} spin-orbit interaction. We show that the standard spin-orbit coupling mechanisms can provide extraordinary efficient electron spin manipulation by an…

Materials Science · Physics 2009-11-10 E. I. Rashba , Al. L. Efros

We study the effect of spin-orbit coupling on quantum gates produced by pulsing the exchange interaction between two single electron quantum dots. Spin-orbit coupling enters as a small spin precession when electrons tunnel between dots. For…

Mesoscale and Nanoscale Physics · Physics 2016-08-31 D. Stepanenko , N. E. Bonesteel , D. P. DiVincenzo , G. Burkard , Daniel Loss

Controlling nanocircuits at the single electron spin level is a possible route for large-scale quantum information processing. In this context, individual electron spins have been identified as versatile quantum information carriers to…

Mesoscale and Nanoscale Physics · Physics 2017-11-01 H. Flentje , P-A. Mortemousque , R. Thalineau , A. Ludwig , A. D. Wieck , C. Bäuerle , T. Meunier

Strong interest has arisen recently on low-dimensional systems with strong spin-orbit interaction due to their peculiar properties of interest for some spintronic applications. Here, the time evolution of the electron spin polarization of a…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 C. Grimaldi

For the realisation of scalable solid-state quantum-bit systems, spins in semiconductor quantum dots are promising candidates. A key requirement for quantum logic operations is a sufficiently long coherence time of the spin system.…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 T. Korn , M. Kugler , M. Griesbeck , R. Schulz , A. Wagner , M. Kubová , C. Gerl , D. Schuh , W. Wegscheider , C. Schüller

Coherent interactions between spins in quantum dots are a key requirement for quantum gates. We have performed pump-probe experiments in which pulsed lasers emitting at different photon energies manipulate two distinct subsets of electron…

Mesoscale and Nanoscale Physics · Physics 2011-10-03 S. Spatzek , A. Greilich , Sophia E. Economou , A. Schwan , S. Varwig , D. R. Yakovlev , D. Reuter , A. D. Wieck , T. L. Reinecke , M. Bayer