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The benefit of exchange-only qubits compared to other spin qubit types is the universal control using only voltage controlled exchange interactions between neighboring spins. As a compromise, qubit operations have to be constructed from…

We show how to construct an arbitrary robust one-qubit unitary operation with a control Hamiltonian of $A_x(t) \sigma_x + A_y(t) \sigma_y$, where $\sigma_i$ is a Pauli matrix and $A_i(t)$ is piecewise constant. Our method, based on planar…

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

All-electrical baseband control of qubits facilitates scaling up quantum processors by removing issues of crosstalk and heat generation. In semiconductor quantum dots, this is enabled by multi-spin qubit encodings, such as the exchange-only…

Mesoscale and Nanoscale Physics · Physics 2025-11-10 Maximilian Rimbach-Russ , Valentin John , Barnaby van Straaten , Stefano Bosco

Quantum control allows a wide range of quantum operations employed in molecular physics, nuclear magnetic resonance and quantum information processing. Thanks to the existing microelectronics industry, semiconducting qubits, where quantum…

Quantum Physics · Physics 2024-12-05 Jia-Ao Peng , Chu-Dan Qiu , Wen-Long Ma , Jun-Wei Luo

Scalable quantum computation in realistic devices requires that precise control can be implemented efficiently in the presence of decoherence and operational errors. We propose a general constructive procedure for designing robust unitary…

Quantum Physics · Physics 2009-04-21 Kaveh Khodjasteh , Lorenza Viola

Here we give an overview of the research on spin-based quantum dot quantum computation. In particular, we discuss the conditions for the Heisenberg exchange Hamiltonian to be a satisfactory description of two-electron interaction in a GaAs…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 Xuedong Hu , S. Das Sarma

The spin states of electrons and holes confined in InAs quantum dot molecules have recently come to fore as a promising system for the storage or manipulation of quantum information. We describe here a feasible scheme for complete quantum…

Mesoscale and Nanoscale Physics · Physics 2015-01-09 Guy Z. Cohen

Motivated by some recent results of quantum control theory, we discuss the feasibility of local operator control in arrays of interacting qubits modeled as isotropic Heisenberg spin chains. Acting on one of the end spins, we aim at finding…

Quantum Physics · Physics 2018-11-13 Rahel Heule , C. Bruder , Daniel Burgarth , Vladimir M. Stojanovic

Low-frequency time-dependent noise is one of the main obstacles on the road towards a fully scalable quantum computer. The majority of solid-state qubit platforms, from superconducting circuits to spins in semiconductors, are greatly…

Quantum Physics · Physics 2021-10-27 Bikun Li , F. A. Calderon-Vargas , Junkai Zeng , Edwin Barnes

We propose a (theoretical ;-) model for quantum computation where the result can be read out from the time average of the Hamiltonian dynamics of a 2-dimensional crystal on a cylinder. The Hamiltonian is a spatially local interaction among…

Quantum Physics · Physics 2007-05-23 Dominik Janzing , Pawel Wocjan

In this article, we develop a numerical method to find optimal control pulses that accounts for the separation of timescales between the variation of the input control fields and the applied Hamiltonian. In traditional numerical…

Quantum Physics · Physics 2011-09-19 F. Motzoi , J. M. Gambetta , S. T. Merkel , F. K. Wilhelm

The author analyzes quantum computation with the hybrid qubit (HQ) that is encoded using the three-electron configuration of a double quantum dot. All gate operations are controlled with electric signals, while the qubit remains at an…

Mesoscale and Nanoscale Physics · Physics 2015-07-14 Sebastian Mehl

We consider the problem of time-optimal control of quadrupole nucleus with the spin I=1 by NMR. In contrast to the conventional methods based on selective pulses, the control is implemented using nonselective pulses separated by free…

Quantum Physics · Physics 2015-06-05 V. P. Shauro

The application of quantum algorithms to the study of many-particle quantum systems requires the ability to prepare wavefunctions that are relevant in the behavior of the system under study. Hamiltonian symmetries are an important…

Quantum Physics · Physics 2022-03-22 Alessandro Carbone , Davide Emilio Galli , Mario Motta , Barbara Jones

Gate-layouts of spin qubit devices are commonly adapted from previous successful devices. As qubit numbers and the device complexity increase, modelling new device layouts and optimizing for yield and performance becomes necessary.…

The ability to manipulate coherently individual quantum objects organized in arrays is a prerequisite to any scalable quantum information platform. For electron spin qubits, it requires the fine tuning of large arrays of tunnel-coupled…

Spin qubits in semiconductor quantum dots represent a prominent family of solid-state qubits in the effort to build a quantum computer. They are formed when electrons or holes are confined in a static potential well in a semiconductor,…

Mesoscale and Nanoscale Physics · Physics 2022-04-12 Shannon Harvey

The spin states of electrons confined in semiconductor quantum dots form a promising platform for quantum computation. Recent studies of silicon CMOS qubits have shown coherent manipulation of electron spin states with extremely high…

Mesoscale and Nanoscale Physics · Physics 2018-10-03 S. D. Liles , R. Li , C. H. Yang , F. E. Hudson , M. Veldhorst , A. S. Dzurak , A. R. Hamilton

The ability to control spins in semiconductors is important in a variety of fields including spintronics and quantum information processing. Due to the potentially fast dephasing times of spins in the solid state [1-3], spin control…