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Abstract
The SI unit system has recently moved away from artificial definitions of units to the elegant quantum definitions based on natural constants. The previous definition of the ampere involved the force between two infinitely long wires, and it is now replaced by the quantum ampere, where current is defined using the elementary charge and caesium frequency standard. Recent developments in quantum technology and nanodevice fabrication have already enabled ondemand singleelectron delivery. Experimental realization of the quantum ampere with closetometrological accuracy was recently demonstrated using singleelectron pumps based on quantum dots with tunablebarriers.
In this thesis, I develop optimization schemes tailored for the experimentally available devices such as singleelectron turnstiles and tunablebarrier quantum pumps. I employ theories of quantum transport for periodically driven systems in the low and highfrequency regimes, to answer the following questions: What is the optimal operation cycle for a quantum pump to achieve high accuracy in the GHz regime? How can we increase the breakdown frequency of singleelectron pumps?
I optimize the regularity of emitted electrons in a turnstile using the distribution of electron waitingtimes. I provide an analytic optimization of twoparameter charge pumps based on the symmetries of the corresponding Berry curvature. For oneparameter pumps, I evaluate the breakdown frequency via a highfrequency expansion and optimize it so that it increases by one order of magnitude. Within the framework of nonequilibrium quantum thermodynamics, I demonstrate how it is possible to maximize the coefficient of performance for coherent pumps.
Translated title of the contribution  Optimization of Quantum Pumps 

Original language  English 
Qualification  Doctor's degree 
Awarding Institution 

Supervisors/Advisors 

Publisher  
Print ISBNs  9789526088808 
Electronic ISBNs  9789526088815 
Publication status  Published  2019 
MoE publication type  G5 Doctoral dissertation (article) 
Keywords
 nanoelectronics
 quantum pumps
 adiabatic pumping
 singleelectron pumps
 counting statistics
 distribution of waiting times
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 1 Finished

Finnish Centre of Excellence in Quantum Technology
Flindt, C., Potanina, E., Burset Atienza, P. & Pyhäranta, T.
01/01/2018 → 31/12/2020
Project: Academy of Finland: Other research funding