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The small footprint of semiconductor qubits is favourable for scalable quantum computing. However, their size also makes them sensitive to their local environment and variations in gate structure. Currently, each device requires tailored…

For certain {\it specific} (or {\it"magic"}) Lamb-Dicke (LD) parameters, Monroe {\it et al} showed [Phys. Rev. {\bf A 55}, R2489 (1997)] that a two-qubit quantum operation, between the external and internal degrees of freedom of a single…

Quantum Physics · Physics 2011-03-07 Miao Zhang , H. Y. Jia , L. F. Wei

We theoretically examine the capacitive coupling between two quantum dot hybrid qubits, each consisting of three electrons in a double quantum dot, as a function of the energy detuning of the double dot potentials. We show that a shaped…

Mesoscale and Nanoscale Physics · Physics 2019-05-08 Arman A. Setser , Jason P. Kestner

We study exchange coupling in Si double quantum dots, which have been proposed as suitable candidates for spin qubits due to their long spin coherence times. We discuss in detail two alternative schemes which have been proposed for…

Mesoscale and Nanoscale Physics · Physics 2010-02-12 Qiuzi Li , Lukasz Cywinski , Dimitrie Culcer , Xuedong Hu , S. Das Sarma

Pulsed lasers offer significant advantages over CW lasers in the coherent control of qubits. Here we review the theoretical and experimental aspects of controlling the internal and external states of individual trapped atoms with pulse…

Atomic Physics · Physics 2015-06-16 J. Mizrahi , B. Neyenhuis , K. Johnson , W. C. Campbell , C. Senko , D. Hayes , C. Monroe

Achieving low-error, exchange-interaction operations in quantum dots for quantum computing imposes simultaneous requirements on the exchange energy's dependence on applied voltages. A double quantum dot (DQD) qubit, approximated with a…

Strongly Correlated Electrons · Physics 2013-05-29 Erik Nielsen , Ralph W. Young , Richard P. Muller , M. S. Carroll

We investigate coherent time-evolution of charge states (pseudo-spin qubit) in a semiconductor double quantum dot. This fully-tunable qubit is manipulated with a high-speed voltage pulse that controls the energy and decoherence of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Toshiaki Hayashi , Toshimasa Fujisawa , Hai-Du Cheong , Yoon-Ha Jeong , Yoshiro Hirayama

We propose a scalable quantum-computing architecture based on cold atoms confined to sites of a tight optical lattice. The lattice is placed in a non-uniform magnetic field and the resulting Zeeman sublevels define qubit states. Microwave…

Quantum Physics · Physics 2009-11-10 Andrei Derevianko , Caleb C. Cannon

We formulate a model of a semiconductor Quantum Dot laser with injection of spin-polarized electrons. As compared to higher-dimensionality structures, the Quantum-Dot-based active region is known to improve laser properties, including the…

Mesoscale and Nanoscale Physics · Physics 2010-09-03 Rafał Oszwałdowski , Christian Gøthgen , Igor Žutić

In this paper, we propose a scheme to implement two-qubit logic gates with a controllable and selective interaction in a scalable superconducting circuit of charge qubits. A nanomechanical resonator is used as a data bus to connect qubits.…

Quantum Physics · Physics 2008-04-01 Jie-Qiao Liao , Qin-Qin Wu , Le-Man Kuang

The behavior of simply pulsed qubits (quantum systems with two linearly independent states) may be characterized by the energy difference $\Delta E$ between the two states of the qubit and by an external stimulating potential $V(t)$ that…

Quantum Physics · Physics 2007-05-23 A. Chalastaras , L. Kaplan , Kh. Kh. Shakov , M. Smith , J. H. McGuire

In double quantum dot singlet-triplet qubits, the exchange interaction is used in both quantum gate operation and the measurement of the state of the qubit. The exchange can be controlled electronically by applying gate voltage pulses. We…

Mesoscale and Nanoscale Physics · Physics 2013-10-21 Tuukka Hiltunen , Juha Ritala , Topi Siro , Ari harju

We characterize the quantum entanglement of the realistic two-qubit signals that are sensitive to charge noises. Our working example is the time response generated from a silicon double quantum dot (DQD) platform, where a single-qubit…

Quantum Physics · Physics 2022-10-12 Junghee Ryu , Hoon Ryu

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

We study the quantum operation of coupled superconducting flux qubits under a microwave irradiation. The flux qubits can be described as magnetic dipole moments in the limit of weak microwave field amplitude consistent with usual…

Superconductivity · Physics 2009-07-09 Mun Dae Kim

We propose a quantum-information processor that consists of decoherence-free logical qubits encoded into arrays of dipole-coupled qubits. High-fidelity single-qubit operations are performed deterministically within a decoherence-free…

Quantum Physics · Physics 2007-05-23 Peter G. Brooke

A novel method of coherent manipulation of the electron tunneling in quantum-dots is proposed, which utilizes the quantum interference in nonadiabatic double-crossing of the discrete energy levels. In this method, we need only a smoothly…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Keiji Saito , Yosuke Kayanuma

We study the orbital and spin dynamics of charge carriers induced by non-overlapping linearly polarized light pulses in semiconductor quantum wells (QWs). It is shown that such an optical excitation with coherent pulses leads to a spin…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 A. V. Poshakinskiy , S. A. Tarasenko

We propose a method for implementation of an universal set of one- and two-quantum-bit gates for quantum computation in the system of two coupled electrons with constant non-diagonal exchange interaction. Suppression of the exchange…

Mesoscale and Nanoscale Physics · Physics 2015-06-23 A. V. Nenashev , A. F. Zinovieva , A. V. Dvurechenskii , A. Yu. Gornov , T. S. Zarodnyuk

Without resorting to spin-spin coupling, we propose a scalable spin quantum computing scheme assisted with a semiconductor multiple-quantum-dot structure. The techniques of single electron transitions and the nanostructure of quantum-dot…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Wei-Min Zhang , Yin-Zhong Wu , Chopin Soo , Mang Feng