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Sensing, localising and identifying individual nuclear spins or frequency components of a signal in the presence of a noisy environments requires the development of robust and selective methods of dynamical decoupling. An important…

We propose a model for spectral diffusion of localized spins in semiconductors due to the dipolar fluctuations of lattice nuclear spins. Each nuclear spin flip-flop is assumed to be independent, the rate for this process being calculated by…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Rogerio de Sousa , S. Das Sarma

Noise spectroscopy elucidates the fundamental noise sources in spin systems, thereby serving as an essential tool toward developing spin qubits with long coherence times for quantum information processing, communication, and sensing. But…

A major challenge in using spins in the solid state for quantum technologies is protecting them from sources of decoherence. This can be addressed, to varying degrees, by improving material purity or isotopic composition for example, or…

Electron spin qubits are a promising platform for quantum computation. Environmental noise impedes coherent operations by limiting the qubit relaxation ($T_1$) and dephasing ($T_{\phi}$) times. There are multiple sources of such noise,…

Quantum Physics · Physics 2022-09-27 Yujun Choi , Robert Joynt

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

Proposed silicon-based quantum-computer architectures have attracted attention because of their promise for scalability and their potential for synergetically utilizing the available resources associated with the existing Si technology…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 S. Das Sarma , Rogerio de Sousa , Xuedong Hu , Belita Koiller

In self assembled III-V semiconductor quantum dots, valence holes have longer spin coherence times than the conduction electrons, due to their weaker coupling to nuclear spin bath fluctuations. Prolonging hole spin stability relies on a…

Mesoscale and Nanoscale Physics · Physics 2016-09-14 M. Vidal , M. V. Durnev , L. Bouet , T. Amand , M. M. Glazov , E. L. Ivchenko , P. Zhou , G. Wang , T. Mano , T. Kuroda , X. Marie , K. Sakoda , B. Urbaszek

The coherence of an electronic spin in a semiconductor quantum dot decays due to its interaction with the bath of nuclear spins in the surrounding isotopes. This effect can be reduced by subjecting the system to an external magnetic field…

Mesoscale and Nanoscale Physics · Physics 2018-07-18 Philipp Schering , Jan Hüdepohl , Götz S. Uhrig , Benedikt Fauseweh

We calculate electron and nuclear spin relaxation rates in a quantum dot due to the combined action of Nyquist noise and electron-nuclei hyperfine or spin-orbit interactions. The relaxation rate is linear in the resistance of the gate…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Florian Marquardt , Veniamin A. Abalmassov

We develop a theory for the spin-echo dynamics of a heavy hole in a quantum dot, accounting for both hyperfine- and electric-field-induced fluctuations. We show that a moderate applied magnetic field can drive this system to a…

Mesoscale and Nanoscale Physics · Physics 2012-12-19 Xiaoya Judy Wang , Stefano Chesi , William A. Coish

Complex quantum systems and their various applications are susceptible to noise of coherent and incoherent nature. Characterization of noise and its sources is an open, key challenge in quantum technology applications, especially in terms…

The central spin decoherence problem has been researched for over 50 years in the context of both nuclear magnetic resonance and electron spin resonance. Until recently, theoretical models have employed phenomenological stochastic…

Mesoscale and Nanoscale Physics · Physics 2012-08-03 Wayne M. Witzel , Malcolm S. Carroll , Lukasz Cywinski , S. Das Sarma

Hole spin qubits are frontrunner platforms for scalable quantum computers because of their large spin-orbit interaction which enables ultrafast all-electric qubit control at low power. The fastest spin qubits to date are defined in long…

Mesoscale and Nanoscale Physics · Physics 2022-10-18 Stefano Bosco , Daniel Loss

Atomic projection noise limits the ultimate precision of all atomic sensors, including clocks, inertial sensors, magnetometers, etc. The independent quantum collapse of $N$ atoms into a definite state (for example spin up or down) leads to…

Atomic Physics · Physics 2015-04-21 Kevin C. Cox , Joshua M. Weiner , Graham P. Greve , James K. Thompson

Noise in contemporary quantum hardware is highly non-uniform across qubits and couplers, giving rise to localized low-noise "islands" within otherwise noisy device topologies. As quantum workloads scale, executions are increasingly forced…

Inevitable interactions with the reservoir largely degrade the performance of non-local gates, which hinders practical quantum computation from coming into existence. Here we experimentally demonstrate a 99.920(7)\%-fidelity controlled-NOT…

Quantum Physics · Physics 2022-12-07 Tianyu Xie , Zhiyuan Zhao , Shaoyi Xu , Xi Kong , Zhiping Yang , Mengqi Wang , Ya Wang , Fazhan Shi , Jiangfeng Du

We experimentally resolve several weakly coupled nuclear spins in diamond using a series of novelly designed dynamical decoupling controls. Some nuclear spin signals, hidden by decoherence under ordinary dynamical decoupling controls, are…

We measure the frequency spectra of random spin fluctuations, or "spin noise", in ensembles of (In,Ga)As/GaAs quantum dots (QDs) at low temperatures. We employ a spin noise spectrometer based on a sensitive optical Faraday rotation…

Mesoscale and Nanoscale Physics · Physics 2010-03-02 S. A. Crooker , J. Brandt , C. Sandfort , A. Greilich , D. R. Yakovlev , D. Reuter , A. D. Wieck , M. Bayer

We have observed millisecond-long coherent evolution of nuclear spins in a quantum wire at 1.2 K. Local, all-electrical manipulation of nuclear spins is achieved by dynamic nuclear polarization in the breakdown regime of the Integer Quantum…

Mesoscale and Nanoscale Physics · Physics 2009-10-01 A. Corcoles , C. J. B. Ford , M. Pepper , G. A. C. Jones , H. E. Beere , D. A. Ritchie