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We describe an interaction mechanism between electron spins in a vertically-stacked double quantum dot that can be used for controlled two-qubit operations. This interaction is mediated by excitons confined within, and delocalized over, the…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 C. Emary , L. J. Sham

Hybrid quantum registers, such as electron-nuclear spin systems, have emerged as promising hardware for implementing quantum information and computing protocols in scalable systems. Nevertheless, the coherent control of such systems still…

Quantum Physics · Physics 2020-07-01 Swathi S. Hegde , Jingfu Zhang , Dieter Suter

Numerous physical systems have been proposed for constructing quantum computers, but formidable obstacles stand in the way of making even modest systems with a few hundred quantum bits (qubits). Several approaches utilize the spin of an…

Other Condensed Matter · Physics 2007-05-23 S. A. Lyon

The electric-field effect on the electronic and magnetic properties of triangular and hexagonal graphene quantum rings with zigzag edge termination is investigated by means of the single-band tight-binding Hamiltonian and the mean-field…

Mesoscale and Nanoscale Physics · Physics 2014-08-29 R. Farghadan , A. Saffarzadeh

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

This paper describes a general method for manipulation of nuclear spins in zero magnetic field. In the absence of magnetic fields, the spins lose the individual information on chemical shifts and inequivalent spins can only be distinguished…

While the helical character of the edge channels responsible for charge transport in the quantum spin Hall regime of a two-dimensional topological insulator is by now well established, an experimental confirmation that the transport in the…

Optically addressed atomic defects in the solid-state are widely used as single-photon sources and memories for quantum network applications. The solid-state environment allows for a high density of electron and nuclear spins with the…

We show how the spin independent scattering between two identical flying qubits can be used to implement an entangling quantum gate between them. We consider one dimensional models with a delta interaction in which the qubits undergoing the…

Quantum Physics · Physics 2011-06-14 Sougato Bose , Vladimir Korepin

We study the low energy states of finite spin chains with isotropic (Heisenberg) and anisotropic (XY and Ising-like) exchange interaction with uniform and non-uniform coupling constants. We show that for an odd number of sites a spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Florian Meier , Jeremy Levy , Daniel Loss

Universal quantum computation requires the implementation of arbitrary control operations on the quantum register. In most cases, this is achieved by external control fields acting selectively on each qubit to drive single-qubit operations.…

Quantum Physics · Physics 2015-06-19 Jingfu Zhang , Daniel Burgarth , Raymond Laflamme , Dieter Suter

We study theoretically the spin transport of a Quantum Spin Hall round disk. When an electron traverses the disk in virtue of the edge states, its spin's in-plane component can be rotated by a magnetic flux through the disk. The spin…

Mesoscale and Nanoscale Physics · Physics 2009-08-07 Zhan-Feng Jiang , Wen-Yu Shan

We present a feasible scheme for performing an optically controlled phase gate between two conduction electron spin qubits in adjacent self assembled quantum dots. Interaction between the dots is mediated by the tunneling of the valence…

Quantum Physics · Physics 2015-05-20 Li-Bo Chen , L. J. Sham , Edo Waks

We fabricated Quantum Dot (QD) devices using a standard SOI CMOS process flow, and demonstrated that the spin of confined electrons could be controlled via a local electrical-field excitation, owing to inter-valley spin-orbit coupling. We…

Electron flying qubits are envisioned as potential information link within a quantum computer, but also promise -- alike photonic approaches -- a self-standing quantum processing unit. In contrast to its photonic counterpart,…

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…

Based on electron spins in semiconductor quantum dots as qubits, a new quantum controlled-NOT(CNOT) gate is constructed in solid nanostructure without resorting to spin-spin interactions. Single electron tunneling technology and coherent…

Quantum Physics · Physics 2009-11-13 Yin-Zhong Wu , Wei-Min Zhang

We demonstrate optical control of the geometric phase acquired by one of the spin states of an electron confined in a charge-tunable InAs quantum dot via cyclic 2pi excitations of an optical transition in the dot. In the presence of a…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Erik D. Kim , Katherine Truex , Xiaodong Xu , Bo Sun , D. G. Steel , A. S. Bracker , D. Gammon , L. J. Sham

The representation of information within the spins of electrons and nuclei has been powerful in the ongoing development of quantum computers. Although nuclear spins are advantageous as quantum bits (qubits) due to their long coherence…

The interaction between two quantum bits enables entanglement, the two-particle correlations that are at the heart of quantum information science. In semiconductor quantum dots much work has focused on demonstrating single spin qubit…

Mesoscale and Nanoscale Physics · Physics 2011-03-14 Danny Kim , Samuel G. Carter , Alex Greilich , Allan Bracker , Daniel Gammon