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In quantum computation, quantum coherence must be maintained during gate operation. However, in physical implementations, various couplings with the environment are unavoidable and can lead to a dephasing of a quantum bit(qubit). The…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Toshifumi Itakura , Yasuhiro Tokura

Charge noise is a major obstacle to improved gate fidelities in silicon spin qubits. Numerous methods exist to mitigate charge noise, including improving device fabrication, dynamical decoupling, and real-time parameter estimation. In this…

Mesoscale and Nanoscale Physics · Physics 2025-05-01 Feiyang Ye , Ammar Ellaboudy , John M. Nichol

The realisation of quantum computers based on molecular electronic spins requires the design of qubits with very long coherence times, T2. Dephasing can proceed over several different microscopic pathways, active at the same time and in…

Materials Science · Physics 2020-01-08 Alessandro Lunghi , Stefano Sanvito

Electron shuttling is one of the current avenues being pursued to scale semiconductor quantum dot-based spin qubits. Adiabatic spin qubit transfer along a chain of tunnel-coupled quantum dots is one of the possible schemes. In this scheme,…

Mesoscale and Nanoscale Physics · Physics 2025-05-13 Jan A. Krzywda , Łukasz Cywiński

Preserving qubit coherence and maintaining high-fidelity qubit control under complex noise environment is an enduring challenge for scalable quantum computing. Here we demonstrate an addressable fault-tolerant single spin qubit with an…

We have studied the electron spin coherence in an ensemble of positively charged InAs/GaAs quantum dots. In a transverse magnetic field, we show that two main contributions must be taken into account to explain the damping of the circular…

Materials Science · Physics 2009-11-13 L. Lombez , P. -F. Braun , X. Marie , P. Renucci , B. Urbaszek , T. Amand , O. Krebs , P. Voisin

We analyze the effects of spin-orbit coupling on fluctuations of the conductance of a quantum dot fabricated in a GaAs heterostructure. We argue that spin-orbit effects may become important in the presence of a large parallel magnetic field…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 B. I. Halperin , Ady Stern , Y. Oreg , J. H. Cremers , J. Folk , C. M. Marcus

In this report, we examine the decoherence of a spin qubits system coupled to counted spin chain with a $1/r^2$ interaction by using influence functional. We also examine the time evolution of density matrix numerically when environment is…

Mesoscale and Nanoscale Physics · Physics 2008-12-20 Toshifumi Itakura

Gate geometry and bias asymmetry can be used to engineer spin dynamics in gate-defined Ge hole quantum dots by reshaping the confinement potential and driving transitions between distinct confinement regimes. In this work, we show that…

Mesoscale and Nanoscale Physics · Physics 2026-04-23 Ngoc Duong , Daryoosh Vashaee

We review recent advances on the theory of spin qubits in nanostructures. We focus on four selected topics. First, we show how to form spin qubits in the new and promising material graphene. Afterwards, we discuss spin relaxation and…

Mesoscale and Nanoscale Physics · Physics 2008-08-29 B. Trauzettel , M. Borhani , M. Trif , D. Loss

For many implementations of quantum computing, 1/f and other types of broad-spectrum noise are an important source of decoherence. An important step forward would be the ability to back out the characteristics of this noise from qubit…

Quantum Physics · Physics 2013-05-29 Dong Zhou , Robert Joynt

A better understanding of the noise causing qubit decoherence is crucial for improving qubit performance. The noise spectrum affecting the qubit may be extracted by measuring dephasing under the application of pulse sequences but requires…

Quantum Physics · Physics 2013-01-10 Thomas Fink , Hendrik Bluhm

We generalize the scattering theory of quantum shot noise to include the full spin-density matrix of electrons injected from a spin-filtering or ferromagnetic electrode into a quantum-coherent nanostructure governed by various…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Ralitsa L. Dragomirova , Branislav K. Nikolic

An all-electrical spin resonance effect in a GaAs few-electron double quantum dot is investigated experimentally and theoretically. The magnetic field dependence and absence of associated Rabi oscillations are consistent with a novel…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 E. A. Laird , C. Barthel , E. I. Rashba , C. M. Marcus , M. P. Hanson , A. C. Gossard

Correlated noise across multiple qubits poses a significant challenge for achieving scalable and fault-tolerant quantum processors. Despite recent experimental efforts to quantify this noise in various qubit architectures, a comprehensive…

Quantum Physics · Physics 2023-08-08 Ji Zou , Stefano Bosco , Daniel Loss

An electron spin qubit in silicon quantum dots holds promise for quantum information processing due to the scalability and long coherence. An essential ingredient to recent progress is the employment of micromagnets. They generate a…

Mesoscale and Nanoscale Physics · Physics 2021-10-26 Peihao Huang , Xuedong Hu

Hybrid systems consisting of different types of qubits are promising for building quantum computers if they combine useful properties of their constituent qubits. However, they also pose additional challenges if one type of qubits is more…

Quantum Physics · Physics 2015-09-16 Jingfu Zhang , Dieter Suter

We consider the relaxation of a spin qubit in a quantum dot propagating as a whole in a one-dimensional semiconductor with hyperfine coupling. We show that this motion leads to qualitatively new features in this process compared to static…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 C. Echeverria-Arrondo , E. Ya. Sherman

We analyze the decoherence dynamics of a central spin coupled to a spin chain with a time-dependent noisy magnetic field, focusing on how noise influences the system's decoherence. Our results show that decoherence due to the nonequilibrium…

Quantum Physics · Physics 2025-05-22 R. Jafari , A. Asadian , M. Abdi , Alireza Akbari

On the quest to understand and reduce environmental noise in Si spin qubits, hyperfine interactions between electron and nuclear spins impose a major challenge. Silicon is a promising host material because one can enhance the spin coherence…

Mesoscale and Nanoscale Physics · Physics 2024-05-20 Lukas Cvitkovich , Peter Stano , Christoph Wilhelmer , Dominic Waldhör , Daniel Loss , Yann-Michel Niquet , Tibor Grasser