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We report the observation of enhanced spin dependent shot noise in magnetic tunnel barriers, suggesting transport through localized states within the barrier. This is supported by the existence of negative magnetoresistance and structure in…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 S. Garzon , Y. Chen , R. A. Webb

We have found experimentally that the shot noise in InAlAs-InGaAs-InAlAs Triple-Barrier Resonant-Tunneling Diodes (TBRTD) is reduced over the 2eI Poissonian value whenever their differential conductance is positive, and is enhanced over 2eI…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. K. M. Newaz , W. Song , Y. Lin , J. Nitta , E. E. Mendez

Noise in entangled quantum systems is difficult to characterize due to many-body effects involving multiple degrees of freedom. This noise poses a challenge to quantum computing, where two-qubit gate performance is critical. Here, we…

We carry out a detailed analysis of coherent resonant tunneling through two coupled quantum dots (CQD) in a parallel arrangement in the weak tunneling limit. We establish a set of quantum rate equations (QREs) in terms of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Bing Dong , X. L. Lei , N. J. M. Horing

We present a theoretical analysis of the effect of inelastic electron scattering on current and its fluctuations in a mesoscopic quantum dot (QD) connected to two leads, based on a recently developed nonperturbative technique involving the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Bing Dong , H. L. Cui , X. L. Lei , Norman J. M. Horing

When an electric current passes across a potential barrier, the partition process of electrons at the barrier gives rise to the shot noise, reflecting the discrete nature of the electric charge. Here we report the observation of excess shot…

We address the shot noise in the tunneling current through a localized spin, pertaining to recent experiments on magnetic adatoms and single molecular magnets. We show that both uncorrelated and spin-correlated scattering processes…

Mesoscale and Nanoscale Physics · Physics 2018-03-16 S. Pradhan , J. Fransson

Semiconductor quantum dot molecules are considered as promising candidates for quantum technological applications due to their wide tunability of optical properties and coverage of different energy scales associated with charge and spin…

In this paper we report a relaxation-induced suppression of the noise for a single level quantum dot coupled to an oscillator with incoherent dynamics in the sequential tunneling regime. It is shown that relaxation induces qualitative…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 F. Haupt , F. Cavaliere , R. Fazio , M. Sassetti

Shot noise measurements on atomic and molecular junctions provide rich information about the quantum transport properties of the junctions and on the inelastic scattering events taking place in the process. Dissipation at the nanoscale, a…

Mesoscale and Nanoscale Physics · Physics 2017-12-11 Sumit Tewari , Carlos Sabater , Manohar Kumar , Stefan Stahl , Bert Crama , Jan M. van Ruitenbeek

We investigate background charge fluctuation in a GaAs quantum dot device by measuring 1/f noise in the single-electron tunneling current through the dot. The current noise is understood as fluctuations of the confinement potential and…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 S. W. Jung , T. Fujisawa , Y. H. Jeong , Y. Hirayama

Quantum noise with exchange and tunneling is studied within time-dependent wave packets. A novel expression for the quantum noise of two identical particles injected simultaneously from opposite sides of a tunneling barrier is presented.…

Quantum Physics · Physics 2016-06-22 Enrique Colomés , Damiano Marian , Xavier Oriols

We have measured the shot noise in a quantum point contact (QPC) fabricated by using InGaAs/InGaAsP heterostructure, whose conductance can be electrically tuned by the gate voltages. The reduced shot noise is observed when the QPC…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Yoshitaka Nishihara , Shuji Nakamura , Kensuke Kobayashi , Teruo Ono , Makoto Kohda , Junsaku Nitta

Coupling a quantum system to a bosonic environment always give rise to inelastic processes, which reduce the coherency of the system. We measure energy dependent rates for inelastic tunneling processes in a fully controllable two-level…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Toshimasa Fujisawa , Wilfred G. van der Wiel , Leo P. Kouwenhoven

Anyonic fractional charges $e^*$ have been detected by autocorrelation shot noise at a quantum point contact (QPC) between two fractional quantum Hall edges. We find that the autocorrelation noise can also show a fingerprint of Abelian…

Mesoscale and Nanoscale Physics · Physics 2019-07-05 Byeongmok Lee , Cheolhee Han , H. -S. Sim

We study a model of two interacting levels that are attached to two electronic leads, where one of the levels is attached very weakly to the leads. We use rate equations method to calculate the average current and the noise of electrons…

Mesoscale and Nanoscale Physics · Physics 2012-02-02 Assaf Carmi , Yuval Oreg

In this paper, we present theoretical investigation of the zero-frequency shot noise spectra in electron tunneling through an interacting quantum dot connected to two ferromagnetic leads with possibility of spin-flip scattering between the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Ivana Djuric , Bing Dong , H. L. Cui

We propose to detect non-Markovian decay of an exciton qubit coupled to multi-mode bosonic reservoir via shot-noise measurements. Non-equilibrium current noise is calculated for a quantum dot embedded inside a \QTR{it}{p-i-n} junction. An…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Yueh-Nan Chen , Guang-Yin Chen

Inherent randomness and the resulting stochastic behavior of fundamental particles manifested as quantum noise put a lower bound on measurement imprecision in the quantum measurement process. In addition, the quantum noise imparts…

Mesoscale and Nanoscale Physics · Physics 2025-01-22 Prasanta Kumbhakar , Anusha Shanmugam , Akhileshwar Mishra , Ravi Pant , J L Reno , S Addamane , Madhu Thalakulam

The fluctuations of electrical current provide information on the dynamics of electrons in quantum devices. Understanding the nature of these fluctuations in a quantum dot is thus a crucial step insofar as this system is the elementary…

Mesoscale and Nanoscale Physics · Physics 2018-10-08 A. Crépieux , S. Sahoo , T. Q. Duong , R. Zamoum , M. Lavagna