Zobrazeno 1 - 10
of 54
pro vyhledávání: '"Vartiainen, Juha"'
Autor:
Kemppinen, Antti, Manninen, Antti J., Möttönen, Mikko, Vartiainen, Juha J., Peltonen, Joonas T., Pekola, Jukka P.
Publikováno v:
Appl. Phys. Lett. 92, 052110 (2008)
We present an experimental study of the magnetic flux dependence of the critical current of a balanced SQUID with three Josephson junctions in parallel. Unlike for ordinary dc SQUIDs, the suppression of the critical current does not depend on the exa
Externí odkaz:
http://arxiv.org/abs/0712.0063
Publikováno v:
Phys. Rev. Lett. 100, 177201 (2008)
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 char
Externí odkaz:
http://arxiv.org/abs/0710.5623
Autor:
Pekola, Jukka P., Vartiainen, Juha J., Mottonen, Mikko, Saira, Olli-Pentti, Meschke, Matthias, Averin, Dmitri V.
The basis of synchronous manipulation of individual electrons in solid-state devices was laid by the rise of single-electronics about two decades ago. Ultra-small structures in a low temperature environment form an ideal domain of addressing electron
Externí odkaz:
http://arxiv.org/abs/0708.1995
Publikováno v:
Applied Physics Letters 90 082102 (2007).
We have employed a tunable Cooper-pair transistor, the sluice, with radio frequency control to pump current over a resistive circuit. We find that the charge transferred per pumping cycle can be controlled with the resolution of a single Cooper-pair
Externí odkaz:
http://arxiv.org/abs/cond-mat/0612556
Publikováno v:
Journal of the Royal Statistical Society: Series C (Applied Statistics) 2007, Vol. 56, 167-181
We study the optimal design of switching measurements of small Josephson junction circuits which operate in the macroscopic quantum tunnelling regime. Starting from the D-optimality criterion we derive the optimal design for the estimation of the unk
Externí odkaz:
http://arxiv.org/abs/cond-mat/0610507
Autor:
Mottonen, Mikko, Pekola, Jukka P., Vartiainen, Juha J., Brosco, Valentina, Hekking, Frank W. J.
Publikováno v:
Phys. Rev. B 73, 214523 (2006)
We present a measurement scheme for observing the Berry phase in a flux assisted Cooper pair pump - the Cooper pair sluice. In contrast to the recent experiments, in which the sluice was employed to generate accurate current through a resistance, we
Externí odkaz:
http://arxiv.org/abs/cond-mat/0604198
Recently it has been shown that time-optimal quantum computation is attained by using the Cartan decomposition of a unitary matrix. We extend this approach by noting that the unitary group is compact. This allows us to reduce the execution time of a
Externí odkaz:
http://arxiv.org/abs/quant-ph/0411153
Publikováno v:
Phys. Rev. A 71, 052330 (2005)
Uniformly controlled one-qubit gates are quantum gates which can be represented as direct sums of two-dimensional unitary operators acting on a single qubit. We present a quantum gate array which implements any n-qubit gate of this type using at most
Externí odkaz:
http://arxiv.org/abs/quant-ph/0410066
Publikováno v:
Quant. Inf. Comp. 5, 467 (2005)
We consider a unitary transformation which maps any given state of an $n$-qubit quantum register into another one. This transformation has applications in the initialization of a quantum computer, and also in some quantum algorithms. Employing unifor
Externí odkaz:
http://arxiv.org/abs/quant-ph/0407010
Publikováno v:
Phys. Rev. Lett. 93, 130502 (2004)
We consider a generic elementary gate sequence which is needed to implement a general quantum gate acting on n qubits -- a unitary transformation with 4^n degrees of freedom. For synthesizing the gate sequence, a method based on the so-called cosine-
Externí odkaz:
http://arxiv.org/abs/quant-ph/0404089