scholarly journals High-efficiency Cooper pair splitting demonstrated by two-particle conductance resonance and positive noise cross-correlation

2012 ◽  
Vol 3 (1) ◽  
Author(s):  
Anindya Das ◽  
Yuval Ronen ◽  
Moty Heiblum ◽  
Diana Mahalu ◽  
Andrey V Kretinin ◽  
...  
2014 ◽  
Vol 28 (21) ◽  
pp. 1450137 ◽  
Author(s):  
Henning Soller

A superconductor connected to normal leads allows to generate Einstein–Podolsky–Rosen pairs by Cooper pair splitting (CPS). It has been realized with quantum dots either defined in carbon nanotubes or InAs nanowires. After establishing the presence of CPS in such devices new works have investigated the effects of a finite potential difference between the quantum dots to improve and characterize the efficiency of CPS. In this paper, we present a generic model for CPS and develop two minimal models specifically for the two experimental realizations and compare them to the experimental data. In addition, we also explore the relation of nonlocal charge transfer to positive current cross-correlation of currents and discuss the temperature dependence of CPS.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Z. B. Tan ◽  
A. Laitinen ◽  
N. S. Kirsanov ◽  
A. Galda ◽  
V. M. Vinokur ◽  
...  

AbstractGeneration of electric voltage in a conductor by applying a temperature gradient is a fundamental phenomenon called the Seebeck effect. This effect and its inverse is widely exploited in diverse applications ranging from thermoelectric power generators to temperature sensing. Recently, a possibility of thermoelectricity arising from the interplay of the non-local Cooper pair splitting and the elastic co-tunneling in the hybrid normal metal-superconductor-normal metal structures was predicted. Here, we report the observation of the non-local Seebeck effect in a graphene-based Cooper pair splitting device comprising two quantum dots connected to an aluminum superconductor and present a theoretical description of this phenomenon. The observed non-local Seebeck effect offers an efficient tool for producing entangled electrons.


2019 ◽  
Vol 1 (3) ◽  
Author(s):  
Mattia Mantovani ◽  
Wolfgang Belzig ◽  
Gianluca Rastelli ◽  
Robert Hussein

2021 ◽  
Author(s):  
◽  
Yannik Behr

<p>We use ambient seismic noise to image the crust and uppermost mantle, and to determine the spatiotemporal characteristics of the noise field itself, and examine the way in which those characteristics may influence imaging results. Surface wave information extracted from ambient seismic noise using cross-correlation methods significantly enhances our knowledge of the crustal and uppermost mantle shear-velocity structure of New Zealand. We assemble a large dataset of three-component broadband continuous seismic data from temporary and permanent seismic stations, increasing the achievable resolution of surface wave velocity maps in comparison to a previous study. Three-component data enables us to examine both Rayleigh and Love waves using noise cross-correlation functions. Employing a Monte Carlo inversion method, we invert Rayleigh and Love wave phase and group velocity dispersion curves separately for spatially averaged isotropic shear velocity models beneath the Northland Peninsula. The results yield first-order radial anisotropy estimates of 2% in the upper crust and up to 15% in the lower crust, and estimates of Moho depth and uppermost mantle velocity compatible with previous studies. We also construct a high-resolution, pseudo-3D image of the shear-velocity distribution in the crust and uppermost mantle beneath the central North Island using Rayleigh and Love waves. We document, for the first time, the lateral extent of low shear-velocity zones in the upper and mid-crust beneath the highly active Taupo Volcanic Zone, which have been reported previously based on spatially confined 1D shear-velocity profiles. Attributing these low shear-velocities to the presence of partial melt, we use an empirical relation to estimate an average percentage of partial melt of < 4:2% in the upper and middle crust. Analysis of the ambient seismic noise field in the North Island using plane wave beamforming and slant stacking indicates that higher mode Rayleigh waves can be detected, in addition to the fundamental mode. The azimuthal distributions of seismic noise sources inferred from beamforming are compatible with high near-coastal ocean wave heights in the period band of the secondary microseism (~7 s). Averaged over 130 days, the distribution of seismic noise sources is azimuthally homogeneous, indicating that the seismic noise field is well-suited to noise cross-correlation studies. This is underpinned by the good agreement of our results with those from previous studies. The effective homogeneity of the seismic noise field and the large dataset of noise cross-correlation functions we here compiled, provide the cornerstone for future studies of ambient seismic noise and crustal shear velocity structure in New Zealand.</p>


2021 ◽  
Author(s):  
Martha Savage ◽  
FC Lin ◽  
John Townend

Measurement of basement seismic resonance frequencies can elucidate shallow velocity structure, an important factor in earthquake hazard estimation. Ambient noise cross correlation, which is well-suited to studying shallow earth structure, is commonly used to analyze fundamental-mode Rayleigh waves and, increasingly, Love waves. Here we show via multicomponent ambient noise cross correlation that the basement resonance frequency in the Canterbury region of New Zealand can be straightforwardly determined based on the horizontal to vertical amplitude ratio (H/V ratio) of the first higher-mode Rayleigh waves. At periods of 1-3 s, the first higher-mode is evident on the radial-radial cross-correlation functions but almost absent in the vertical-vertical cross-correlation functions, implying longitudinal motion and a high H/V ratio. A one-dimensional regional velocity model incorporating a ~ 1.5 km-thick sedimentary layer fits both the observed H/V ratio and Rayleigh wave group velocity. Similar analysis may enable resonance characteristics of other sedimentary basins to be determined. © 2013. American Geophysical Union. All Rights Reserved.


2015 ◽  
Vol 202 (1) ◽  
pp. 604-611 ◽  
Author(s):  
Gaia Soldati ◽  
Lucia Zaccarelli ◽  
Licia Faenza ◽  
Alberto Michelini

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