Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1209.3626 · Physical Review B

Coherent Cooper-pair pumping by magnetic flux control

Simone Gasparinetti, I. Kamleitner

Published Dec 17, 2012• 5 citations
arXivHTMLPDF

Abstract

We introduce and discuss a scheme for Cooper-pair pumping. The scheme relies on the coherent transfer of a superposition of charge states across a superconducting island and is realized by adiabatic manipulation of magnetic fluxes. Differently from previous implementations, it does not require any modulation of electrostatic potentials. We find a peculiar dependence of the pumped charge on the superconducting phase bias across the pump and that an arbitrarily large amount of charge can be pumped in a single cycle when the phase bias is $\ensuremath{\pi}$. We explain these features and their relation to the adiabatic theorem.

DOI
10.1103/physrevb.86.224510

Related papers

Measurement of coherent charge transfer in an adiabatic Cooper-pair pump

Rosario Fazio, F. W. J. Hekking, Jukka P Pekola

We study adiabatic charge transfer in a superconducting Cooper-pair pump, focusing on the influence of current measurement on coherence. We investigate the limit where the Josephson coupling energy ${E}_{J}$ between the various parts of the system is small compared to the Coulomb charging energy ${E}_{C}.$ In this case, the charge transferred in a pumping cycle ${Q}_{P}\ensuremath{\sim}2e,$ the charge of one Cooper pair: The main contribution is due to incoherent Cooper-pair tunneling. We are particularly interested in the quantum correction to ${Q}_{P},$ which is due to coherent tunneling of pairs across the pump and which depends on the superconducting phase difference ${\ensuremath{\varphi}}_{0}$ between the electrodes; $1\ensuremath{-}{Q}_{P}/(2e)\ensuremath{\sim}{(E}_{J}{/E}_{C})\mathrm{cos}{\ensuremath{\varphi}}_{0}.$ A measurement of ${Q}_{P}$ tends to destroy the phase coherence. We first study an arbitrary measuring circuit and then specific examples and show that coherent Cooper-pair transfer can, in principle, be detected using an inductively shunted ammeter.

arXiv:cond-mat/0302383•Physical review. B, Condensed matter•Aug 7, 2003•24 citations

Flux Pumping of Cooper Pairs Through a Josephson Energy-Suppression Pump

Angelo Greco, Luca Fasolo, Vito Marino +1 more

In this paper, we propose a novel kind of Josephson Energy Suppression Pump (JESP) controlled by a fully magnetic flux drive. The device presented here is composed of two superconducting loops interrupted at one side by superconducting nanowires which are joined together by a superconducting island. The phase difference developed at the edges of the nanowires by means of the magnetic flux threading the loops can collapse their Cooper condensates, leading to complete suppression of the Josephson energies. This mechanism allows to greatly reduce the leakage current when performing Cooper pair pumping by a pure magnetic pumping cycle without involving any gate modulation. The pumping capability of the JESP is studied through a master equation approach in the non-adiabatic case.

arXiv:2109.13758•IEEE Transactions on Applied Superconductivity•Dec 14, 2021•1 citation

Evidence of Cooper-pair pumping with combined flux and voltage control

A. O. Niskanen, Jani M. Kivioja, Heikki Seppä +1 more

We have experimentally demonstrated pumping of Cooper pairs in a single-island mesoscopic structure. The island was connected to leads through SQUID (superconducting quantum interference device) loops. Synchronized flux and voltage signals were applied whereby the Josephson energies of the SQUIDs and the gate charge were tuned adiabatically. From the current-voltage characteristics one can see that the pumped current increases in $1e$ steps which is due to quasiparticle poisoning on the measurement time scale, but we argue that the transport of charge is due to Cooper pairs.

arXiv:cond-mat/0410758•Physical Review B•Jan 26, 2005•24 citations

Experimental Determination of the Berry Phase in a Superconducting Charge Pump

Mikko Möttönen, Juha J. Vartiainen, Jukka P Pekola

We present the first measurements of the Berry phase in a superconducting Cooper pair pump. A fixed amount of Berry phase is accumulated to the quantum-mechanical ground state in each adiabatic pumping cycle, which is determined by measuring the charge passing through the device. The dynamic and geometric phases are identified and measured quantitatively from their different response when pumping in opposite directions. Our observations, in particular, the dependencies of the dynamic and geometric effects on the superconducting phase bias across the pump, agree with the basic theoretical model of coherent Cooper pair pumping.

arXiv:0710.5623•Physical Review Letters•Apr 28, 2008•117 citations

Cooper pair sluice: A fast and accurate single-island charge pump

A. O. Niskanen, Jani M. Kivioja, Jukka P Pekola +1 more

We have carried out first measurements on a novel type of a charge pump nicknamed the Cooper pair "sluice". The device is an adiabatic flux-assisted Cooper pair pump consisting of a mesoscopic superconducting island and of two SQUID loops. The operation is based on the periodic manipulation of a single voltage gate and two input coils controlling the magnetic flux through the SQUID loops. Based on theoretical estimates the device is capable of producing as high as 0.1 nA currents at better than 10-accuracy and looks thus like a promising candidate for the current source in completing the quantum measurement triangle. In spite of several nonidealities in our preliminary measurement setup, we have succeeded in verifying the pumping behavior of the sluice. The pumped currents were quite high, several hundred pA, but the accuracy needs to be increased. The results obtained so far suggest various ways of improving the measurement setup

Conference on Precision Electromagnetic Measurements•Jun 1, 2004•2 citations

Controlled transfer of single charge carriers

C. Urbina, H. Pothier, P. Lafarge +7 more

Two devices that allow the coherent transfer of single electrons are described. They are based on the electrostatic control of tunnel processes across ultrasmall normal tunnel junctions. When appropriate AC signals are applied to gates a current I=e*f is forced to flow through the devices. There are, however, fundamental differences in their principles which make the pump the only suitable candidate for the controlled transfer of cooper pairs. Although in these experiments the I=e*f relation was verified with only a 1% accuracy, more elaborate versions of these devices could be promising candidates for a current standard.

IEEE Transactions on Magnetics•Mar 1, 1991•30 citations
We introduce and discuss a scheme for Cooper-pair pumping. The scheme relies on the coherent transfer of a superposition of charge states across a superconducting island and is realized by adiabatic manipulation of magnetic fluxes. Differently from previous implementations, it does not require any modulation of electrostatic potentials. We find a peculiar dependence of the pumped charge on the superconducting phase bias across the pump and that an arbitrarily large amount of charge can be pumped in a single cycle when the phase bias is \ensuremathπ\ensuremath{\pi}\ensuremathπ. We explain these features and their relation to the adiabatic theorem.
We study adiabatic charge transfer in a superconducting Cooper-pair pump, focusing on the influence of current measurement on coherence. We investigate the limit where the Josephson coupling energy EJ{E}_{J}EJ​ between the various parts of the system is small compared to the Coulomb charging energy EC.{E}_{C}.EC​. In this case, the charge transferred in a pumping cycle ${Q}_{P}\ensuremath{\sim}2e,$ the charge of one Cooper pair: The main contribution is due to incoherent Cooper-pair tunneling. We are particularly interested in the quantum correction to QP,{Q}_{P},QP​, which is due to coherent tunneling of pairs across the pump and which depends on the superconducting phase difference ${\ensuremath{\varphi}}_{0}$ between the electrodes; $1\ensuremath{-}{Q}_{P}/(2e)\ensuremath{\sim}{(E}_{J}{/E}_{C})\mathrm{cos}{\ensuremath{\varphi}}_{0}.$ A measurement of QP{Q}_{P}QP​ tends to destroy the phase coherence. We first study an arbitrary measuring circuit and then specific examples and show that coherent Cooper-pair transfer can, in principle, be detected using an inductively shunted ammeter.
In this paper, we propose a novel kind of Josephson Energy Suppression Pump (JESP) controlled by a fully magnetic flux drive. The device presented here is composed of two superconducting loops interrupted at one side by superconducting nanowires which are joined together by a superconducting island. The phase difference developed at the edges of the nanowires by means of the magnetic flux threading the loops can collapse their Cooper condensates, leading to complete suppression of the Josephson energies. This mechanism allows to greatly reduce the leakage current when performing Cooper pair pumping by a pure magnetic pumping cycle without involving any gate modulation. The pumping capability of the JESP is studied through a master equation approach in the non-adiabatic case.
We have experimentally demonstrated pumping of Cooper pairs in a single-island mesoscopic structure. The island was connected to leads through SQUID (superconducting quantum interference device) loops. Synchronized flux and voltage signals were applied whereby the Josephson energies of the SQUIDs and the gate charge were tuned adiabatically. From the current-voltage characteristics one can see that the pumped current increases in 1e1e1e steps which is due to quasiparticle poisoning on the measurement time scale, but we argue that the transport of charge is due to Cooper pairs.
We present the first measurements of the Berry phase in a superconducting Cooper pair pump. A fixed amount of Berry phase is accumulated to the quantum-mechanical ground state in each adiabatic pumping cycle, which is determined by measuring the charge passing through the device. The dynamic and geometric phases are identified and measured quantitatively from their different response when pumping in opposite directions. Our observations, in particular, the dependencies of the dynamic and geometric effects on the superconducting phase bias across the pump, agree with the basic theoretical model of coherent Cooper pair pumping.
We have carried out first measurements on a novel type of a charge pump nicknamed the Cooper pair "sluice". The device is an adiabatic flux-assisted Cooper pair pump consisting of a mesoscopic superconducting island and of two SQUID loops. The operation is based on the periodic manipulation of a single voltage gate and two input coils controlling the magnetic flux through the SQUID loops. Based on theoretical estimates the device is capable of producing as high as 0.1 nA currents at better than 10-accuracy and looks thus like a promising candidate for the current source in completing the quantum measurement triangle. In spite of several nonidealities in our preliminary measurement setup, we have succeeded in verifying the pumping behavior of the sluice. The pumped currents were quite high, several hundred pA, but the accuracy needs to be increased. The results obtained so far suggest various ways of improving the measurement setup
Two devices that allow the coherent transfer of single electrons are described. They are based on the electrostatic control of tunnel processes across ultrasmall normal tunnel junctions. When appropriate AC signals are applied to gates a current I=e*f is forced to flow through the devices. There are, however, fundamental differences in their principles which make the pump the only suitable candidate for the controlled transfer of cooper pairs. Although in these experiments the I=e*f relation was verified with only a 1% accuracy, more elaborate versions of these devices could be promising candidates for a current standard.