Biomedical subjects

Pauli Virtanen

Publications and source records attributed to Pauli Virtanen.

3 recordsLinked to original sources

PubMed2006

Supercurrent-induced temperature gradient across a nonequilibrium SNS Josephson junction.

Using tunneling spectroscopy, we have measured the local electron energy distribution function in the normal part of a superconductor-normal metal-superconductor (SNS) Josephson junction containing an extra lead to a normal reservoir. In the presence of simultaneous supercurrent and injected quasiparticle current, the distribution function exhibits a sharp feature at very low energy. The feature is odd in energy and odd under reversal of either the supercurrent or the quasiparticle current direction. The feature represents an effective temperature gradient across the SNS Josephson junction that is controllable by the supercurrent.

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PubMed2004

Measuring non-Gaussian fluctuations through incoherent cooper-pair current.

We study a Josephson junction (JJ) in the regime of incoherent Cooper-pair tunneling, capacitively coupled to a nonequilibrium noise source. The current-voltage (I-V) characteristics of the JJ are sensitive to the excess voltage fluctuations in the source, and can thus be used for wideband noise detection. Under weak driving, the odd part of the I-V can be related to the second cumulant of noise, whereas the even part is due to the third cumulant. After calibration, one can measure the Fano factors for the noise source, and get information about the frequency dependence of the noise.

Journal Article↗

PubMed2004

Thermopower induced by a supercurrent in superconductor-normal-metal structures.

We examine the thermopower Q of a mesoscopic normal-metal (N) wire in contact with superconducting (S) segments and show that even with electron-hole symmetry Q may become finite due to the presence of supercurrents. Moreover, we show how the dominant part of Q can be directly related to the equilibrium supercurrents in the structure. In general, a finite thermopower appears both between the N reservoirs and the superconductors and between the N reservoirs themselves. The latter, however, strongly depends on the geometrical symmetry of the structure.

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