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We investigate the propagation of a piezoelectric surface acoustic wave (SAW) across a GaAs/Al$_X$Ga$_{1-X}$As heterostructure surface, on which there is fixed a metallic split-gate. Our method is based on a finite element formulation of…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 S. Rahman , M. Kataoka , C. H. W. Barnes , H. P. Langtangen

Spin qubits in Silicon quantum dots can have long coherence times, yet their manipulation relies on the exchange interaction, through which charge noise can induce decoherence. Charge traps near the interface of a Si heterostructure lead to…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Dimitrie Culcer , Xuedong Hu , S. Das Sarma

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 considered various types of potential noise in gates controlling non-adiabatic holonomic transformations of spin-qubits in one and two dimensional systems with the Rashba interaction. It is shown how exact results can be derived for…

Mesoscale and Nanoscale Physics · Physics 2017-11-10 Lara Ulčakar , Anton Ramšak

We investigate current fluctuations in non-degenerate semiconductors, on length scales intermediate between the elastic and inelastic mean free paths. We present an exact solution of the non-linear kinetic equations in the regime of…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 H. Schomerus , E. G. Mishchenko , C. W. J. Beenakker

We obtain exact expressions for the local current and shot noise and the nonlocal shot noise in the first propagating channel of an NSN (normal-superconducting-normal) nanowire. Using high-$T_c$ cuprate superconductors (HTS) as our model…

Superconductivity · Physics 2019-05-01 Corey Ostrove , Linda E. Reichl

Charge qubits formed in double quantum dots represent quintessential two-level systems that enjoy both ease of control and efficient readout. Unfortunately, charge noise can cause rapid decoherence, with typical single-qubit gate fidelities…

Mesoscale and Nanoscale Physics · Physics 2019-03-11 Yuan-Chi Yang , S. N. Coppersmith , Mark Friesen

We study the electrical transport properties of a quantum point contact between a lead and a Hight Tc superconductor. For this, we use the Hamiltonian approach and non-equilibrium Green functions of the system. The electrical current and…

Superconductivity · Physics 2012-10-19 J. A. Celis G. , William J. Herrera

Electrical conductance measurements have limited scope in identifying Andreev edge states (AESs), which form the basis for realizing various topological excitations in quantum Hall (QH) - superconductor (SC) junctions. To unambiguously…

The shot noise in tunneling experiments reflects the Poissonian nature of the tunneling process. The shot noise power is proportional to both the magnitude of the current and the effective charge of the carrier. Shot noise spectroscopy thus…

We present a method for estimating the number of shots required to achieve a desired variance in the results of a quantum circuit. First, we establish a baseline for single-qubit characterisation of individual noise sources. We then move on…

Quantum Physics · Physics 2026-01-30 Manav Seksaria , Anil Prabhakar

We show that shot noise can be used for studies of hopping and resonant tunnelling between localised electron states. In hopping via several states, shot noise is seen to be suppressed compared with its classical Poisson value $S_I=2eI$…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. K. Savchenko , S. S. Safonov , S. H. Roshko , D. A. Bagrets , O. N. Jouravlev , Y. V. Nazarov , E. H. Linfield , D. A. Ritchie

Recent proposals for building scalable quantum computational devices in semi-conductor based spin qubits introduce shared control lines in order to reduce the overhead of qubits controls. In principle, noises from the shared controls could…

Quantum Physics · Physics 2024-02-16 Yinan Fang

We develop a system for measurements of power spectra of transmitted light intensity fluctuations, in which the extraneous noise, including shot noise, is reduced. In essence, we just apply light, measure the power of the transmitted light…

Atomic Physics · Physics 2023-07-19 Takahisa Mitsui , Kenichiro Aoki

Using the 'drift-diffusion-Langevin' equation, we have quantitatively analyzed the effects of electron energy relaxation via their interaction with phonons, generally in presence of electron-electron interaction, on shot noise in diffusive…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Y. Naveh , D. V. Averin , K. K. Likharev

Electron spins in silicon quantum dots provide a promising route towards realising the large number of coupled qubits required for a useful quantum processor. At present, the requisite single-shot spin qubit measurements are performed using…

We propose a theoretical model for the low-frequency noise observed in a quantum point contact (QPC) electrostatically defined in the 2D electron gas at a GaAs-AlGaAs interface. In such contacts electron scattering by soft impurity- or…

Condensed Matter · Physics 2009-10-22 J. P. Hessling , Yu. Galperin , M. Jonson , R. I. Shekhter , A. M. Zagoskin

The shot noise suppression in a sample containing a layer of self-assembled InAs quantum dots has been investigated experimentally and theoretically. The observation of a non-monotonic dependence of the Fano factor on the bias voltage in a…

Condensed Matter · Physics 2007-05-23 G. Kiesslich , A. Wacker , E. Schoell , A. Nauen , F. Hohls , R. J. Haug

A simple equivalent circuit, which describes transport properties of a Two Dimensional Electron Gas in the Fractional Quantum Hall regime is presented. The physical justifications for this equivalent circuit are discussed in the frame work…

Mesoscale and Nanoscale Physics · Physics 2009-09-25 R. de Picciotto

We report the experimental observation of sub-Poissonian shot noise in single magnetic tunnel junctions, indicating the importance of tunneling via impurity levels inside the tunnel barrier. For junctions with weak zero-bias anomaly in…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 R. Guerrero , F. G. Aliev , Y. Tserkovnyak , T. S. Santos , J. S. Moodera