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We demonstrate high speed manipulation of a few-electron double quantum dot. In the one-electron regime, the double dot forms a charge qubit. Microwaves are used drive transitions between the (1,0) and (0,1) charge states of the double dot.…

Mesoscale and Nanoscale Physics · Physics 2010-10-05 J. R. Petta , A. C. Johnson , J. M. Taylor , A. Yacoby , M. D. Lukin , C. M. Marcus , M. P. Hanson , A. C. Gossard

We simulate the control of the spin states in a two-electron double quantum dot when an external detuning potential is used for passing the system through an anticrossing. The hyperfine coupling of the electron spins with the surrounding…

Mesoscale and Nanoscale Physics · Physics 2011-04-12 Jani Särkkä , Ari Harju

The spin dynamics of radical-triplet system (RTS) has been calculated by using the Lindblad formalism within the theory of open quantum system. The single-radical-triplet system (SRTS) is considered here for single-qubit quantum gate…

Quantum Physics · Physics 2015-01-05 Wei Wu

We present a theory for the dissipation of electronic spins trapped in quantum dots due to their coupling to the host lattice acoustic phonon modes. Based on the theory of dissipative two level systems for the spin dynamics, we derive a…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Harry Westfahl , Amir O. Caldeira , Gilberto Medeiros-Ribeiro , Maya Cerro

We study the spin relaxation in an interacting two--dimensional electron gas in a strong magnetic field for the case that the electron density is close to filling just one Landau sub--level of one spin projection, i.e., for filling factor…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 W. Apel , Yu. A. Bychkov

Spin relaxation from a triplet excited state to a singlet ground state in a semiconductor quantum dot is studied by employing an electrical pump-and-probe method. Spin relaxation occurs via cotunneling when the tunneling rate is relatively…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 S. Sasaki , T. Fujisawa , T. Hayashi , Y. Hirayama

The magnetic-field evolution of Coulomb blockade peaks in lateral InGaAs/InAlAs quantum dots in the few-electron regime is reported. Quantum dots are defined by gates evaporated onto a 60 nm-thick hydrogen silsesquioxane insulating film. A…

Mesoscale and Nanoscale Physics · Physics 2010-07-02 F. Deon , V. Pellegrini , F. Carillo , F. Giazotto , L. Sorba , G. Biasiol , F. Beltram

We propose to use the spin-blockade regime in double quantum dots to reduce nuclear spin polarization fluctuations in analogy with optical Doppler cooling. The Overhauser shift brings electron levels in and out of resonance, creating…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. S. Rudner , L. S. Levitov

We demonstrate electrical control of the spin relaxation time T_1 between Zeeman split spin states of a single electron in a lateral quantum dot. We find that relaxation is mediated by the spin-orbit interaction, and by manipulating the…

Mesoscale and Nanoscale Physics · Physics 2010-09-28 S. Amasha , K. MacLean , Iuliana P. Radu , D. M. Zumbuhl , M. A. Kastner , M. P. Hanson , A. C. Gossard

The temperature-dependent electron spin relaxation of positively charged excitons in a single InAs quantum dot (QD) was measured by time-resolved photoluminescence spectroscopy at zero applied magnetic fields. The experimental results show…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 X. M. Dou , B. Q. Sun , D. S. Jiang , H. Q. Ni , Z. C. Niu

Optically active quantum dot molecules (QDMs) can host multi-spin quantum states with the potential for the deterministic generation of photonic graph states with tailored entanglement structures. Their usefulness for the generation of such…

We investigate charge relaxation rates due to acoustic phonons in weakly-confined quantum dot systems, including both deformation potential and piezoelectric field interactions. Single-electron excited states lifetimes are calculated for…

Mesoscale and Nanoscale Physics · Physics 2007-10-30 J. I. Climente , A. Bertoni , G. Goldoni , E. Molinari

Highly accurate numerical results of phonon-induced two-electron spin relaxation in silicon double quantum dots are presented. The relaxation, enabled by spin-orbit coupling and the nuclei of $^{29}$Si (natural or purified abundance), are…

Mesoscale and Nanoscale Physics · Physics 2013-02-01 Martin Raith , Peter Stano , Jaroslav Fabian

We calculate spin relaxation rates in lateral quantum dot systems due to electron exchange between dots and leads. Using rate equations, we develop a theoretical description of the experimentally observed electric current in the spin…

Mesoscale and Nanoscale Physics · Physics 2008-12-08 A. B. Vorontsov , M. G. Vavilov

We study acoustic-phonon-induced relaxation of charge excitations in single and tunnel-coupled quantum dots containing few confined interacting electrons. The Full Configuration Interaction approach is used to account for the…

Mesoscale and Nanoscale Physics · Physics 2007-10-30 Juan I. Climente , Andrea Bertoni , Massimo Rontani , Guido Goldoni , Elisa Molinari

We present a theoretical analysis of the phonon-assisted relaxation in a system composed of two self-assembled vertically stacked quantum dots. We construct realistic model, which takes into account the geometry and strain distribution in…

Mesoscale and Nanoscale Physics · Physics 2013-01-16 Krzysztof Gawarecki , Paweł Machnikowski

Exchange-coupled singlet-triplet spin qubits in two gate-defined double quantum dots are considered theoretically. Using charge density operators to describe the double-dot orbital states, we calculate the Coulomb couplings between the…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Guy Ramon

The study of charge and spin transport through semiconductor quantum dots is experiencing a renaissance due to recent advances in nano-fabrication and the realization of quantum dots as candidates for quantum computing. In this work, we…

Mesoscale and Nanoscale Physics · Physics 2021-02-17 John P. Philbin , Amikam Levy , Prineha Narang , Wenjie Dou

The spin relaxation time due to the electron-acoustic phonon scattering in GaAs quantum dots is studied after the exact diagonalization of the electron Hamiltonian with the spin-orbit coupling. Different effects such as the magnetic field,…

Condensed Matter · Physics 2012-07-02 J. L. Cheng , M. W. Wu , C. Lü

The magnetic field dependence of the electronic properties of \textit{real} single vertical quantum dots in circular and rectangular mesas is investigated within a full three-dimensional multiscale self-consistent approach without any {\it…