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We demonstrate coherent optical control of a single hole spin confined to an InAs/GaAs quantum dot. A superposition of hole spin states is created by fast (10-100 ps) dissociation of a spin-polarized electron-hole pair. Full control of the…

Mesoscale and Nanoscale Physics · Physics 2012-01-09 T. M. Godden , J. H. Quilter , A. J. Ramsay , Yanwen Wu , P. Brereton , S. J. Boyle , I. J. Luxmoore , J. Puebla-Nunez , A. M. Fox , M. S. Skolnick

Semiconductor point contacts can be a useful tool for producing spin-polarized currents in the presence of spin-orbit (SO) interaction. Neither magnetic fields nor magnetic materials are required. By numerical studies, we show that (i) the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Mikio Eto , Tetsuya Hayashi , Yuji Kurotani

We consider the full driven quantum dynamics of a qubit realized as spin of electron in a one-dimensional double quantum dot with spin-orbit coupling. The driving perturbation is taken in the form of a single half-period pulse of electric…

Mesoscale and Nanoscale Physics · Physics 2010-09-28 D. V. Khomitsky , E. Ya. Sherman

We propose a novel scheme to efficiently polarize and manipulate the electron spin in a quantum dot. This scheme is based on the spin-orbit interaction and it possesses following advantages: (1) The direction and the strength of the spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Qing-feng Sun , X. C. Xie

We study controllable exchange coupling between two singlet-triplet qubits. We start from the original second quantized Hamiltonian of a quadruple quantum dot system and obtain the effective spin-spin interaction between the two qubits…

Mesoscale and Nanoscale Physics · Physics 2013-05-13 Rui Li , Xuedong Hu , J. Q. You

We propose a method to construct composite two-qubit gates with narrowband profiles with respect to the spin-spin coupling. The composite sequences are selective to the variations in the amplitude and duration of the spin-spin coupling, and…

Quantum Physics · Physics 2022-06-30 Boyan T. Torosov , Nikolay V. Vitanov

Inverse engineering of electric fields has been recently proposed to achieve fast and robust spin control in a single-electron quantum dot with spin-orbit coupling. In this paper we design, by inverse engineering based on Lewis-Riesenfeld…

Quantum Physics · Physics 2013-09-10 Yue Ban , Xi Chen , J. G. Muga , E. Ya Sherman

We propose and demonstrate complete spin state readout of a two-electron system in a double quantum dot probed by an electrometer. The protocol is based on repetitive single shot measurements using Pauli spin blockade and our ability to…

We show that the electron spin polarization generated by an electrical current may have its direction controlled and magnitude amplified by periodic optical excitation. The electrical and optical spin control methods were combined and…

Mesoscale and Nanoscale Physics · Physics 2014-07-17 Felix G. G. Hernandez , Gennady M. Gusev , Askhat K. Bakarov

The effective interaction between magnetic impurities in metals that can lead to various magnetic ground states often competes with a tendency for electrons near impurities to screen the local moment (Kondo effect). The simplest system…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 N. J. Craig , J. M. Taylor , E. A. Lester , C. M. Marcus , M. P. Hanson , A. C. Gossard

In this paper we treat the 2--level system interacting with external fields without the rotating wave approximation and construct some approximate solutions in the strong coupling regime.

Quantum Physics · Physics 2007-05-23 Kazuyuki Fujii

Synthetic spin-orbit coupling in cold atoms couples the pseudo-spin and spatial degrees of freedom, and therefore the inherent spin symmetry of the system plays an important role. In systems of two pseudo-spin degrees, two particles contain…

Quantum Gases · Physics 2025-02-05 Ayaka Usui , Abel Rojo-Francàs , James Schloss , Bruno Juliá-Díaz

The generated magnitude of quadrature squeezing in a cavity-coupled ensemble, which is continuously driven using a coherent off-axis field, is theoretically explored. Using a truncated set of equations-of-motion derived from a Dicke…

Quantum Physics · Physics 2021-02-05 Haitham A. R. El-Ella

A ring structure fabricated from GaAs is used to achieve interference of the net spin polarization of conduction band electrons. Optically polarized spins are split into two packets by passing through two arms of the ring in the diffusive…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Y. K. Kato , R. C. Myers , A. C. Gossard , D. D. Awschalom

Spin chains can be used to describe a wide range of platforms for quantum computation and quantum information. They enable the understanding, demonstration, and modeling of numerous useful phenomena, such as high fidelity transfer of…

Quantum Physics · Physics 2023-08-14 Abdulsalam H. Alsulami , Irene D'Amico , Marta P. Estarellas , Timothy P. Spiller

We investigate a hybrid quantum system involving spin qubits, based on the spins of electrons confined in quantum dots, and topological qubits, based on Majorana fermions. In such a system, gated control of the charge on the quantum dots…

Mesoscale and Nanoscale Physics · Physics 2013-01-10 Martin Leijnse , Karsten Flensberg

Amplitude and phase control of gain without inversion is investigated in a four level loop-structure atomic system. Two features are presented. One is that gain without inversion can be obtained through the amplitude control of the applied…

Optics · Physics 2013-11-12 Jinhua Zou , Dahai Xu , Huafeng Zhang

An exact and analytic control protocol of two types of finite dimensional quantum systems is proposed. The system can be drive to an arbitrary target state using cosine classical fields in finite cycles. The control parameters which are…

Quantum Physics · Physics 2015-06-12 Jianju Tang , H. C. Fu

We put forward reverse engineering protocols to shape in time the components of the magnetic field to manipulate a single spin, two independent spins with different gyromagnetic factors, and two interacting spins in short amount of times.…

Quantum Physics · Physics 2018-01-29 Qi Zhang , Xi Chen , D. Guery-Odelin

We develop energy efficient, continuous microwave schemes to couple electron and nuclear spins, using phase or amplitude modulation to bridge their frequency difference. These controls have promising applications in biological systems,…

Quantum Physics · Physics 2019-01-14 J. Casanova , E. Torrontegui , M. B. Plenio , J. J. García-Ripoll , E. Solano