PICO-group SAB presentation, Nov 9, 2006, Jukka Pekola

Dr. Alexander Savin senior scientist

Dr. Matthias Meschke research scientist

Dr. Juha Vartiainen post doc researcher

Dr. Mikko Möttönenpost doc researcher (partly at the Laboratory of Physics, TKK)

Andrey Timofeevgraduate student

Tommy Holmqvist graduate student

Olli-Pentti Saira diploma student

Joonas Peltonen(part time)

Laura MacDonald(part time)

Kurt Baarman(part time)

Antti Kemppinengraduate student(MIKES)

Main activities in 2005 - 06

Thermal effects and thermodynamics on a chip

Josephson junction detector of noise and FCS [poster by Andrey Timofeev, presentation by Tero Heikkilä, poster by Teemu Ojanen]

Cooper pair pumping and Berry phase [partly covered in the presentation of Antti Manninen]

High resolution superconducting single flux quantum comparators for sub kelvin temperatures [VTT presentation/poster]

Lattice

Electrical environment

Electron system

TODAY

Heat transported between two resistors

Impedance matching (= channel transmission):

Radiative contribution to net heat flow between electrons of 1 and 2:

Linear response for small temperature difference T = Te1 – Te2:

Quantized heat conduction

J. Pendry (1983), ”Quantum limits to the flow of information and entropy”: single channel heat conduction limited by GQ (phonons,

photons, any carriers)

K. Schwab et al. (2000), experiment with phonons

D.R. Schmidt et al. (2004), predictions for photon coupling

O. Chiatti et al. (2006), measurement with electrons in a 1D wire

Experimental set-up

10 µm

R2 R1

x

xx

x

LJCJ

Experimental results

90

95

100

105

110

115

120

125

155

160

165

170

105mK

118mK

T0 = 167mK

60mK

75mK

157mK

T

(

mK

)

(a.u.)

e1

R2 R1

x

xx

x

LJCJ

Research topics for 2007 - 2009

Thermal effects:Influence of Coulomb blockade on electron cooling (2007)Cyclic electronic refrigerator (2007 - 08)Cooling by thermal noise (2007 – 09)Quantized thermal conductance by photons over mm distances (2008 – 09)

Noise and full counting statistics using a Josephson junction detector:Asymmetry of shot noise of a tunnel junction at high frequencies, comparison to theories (2007)Noise spectroscopy at 1 - 100 GHz frequencies (2007 – 08)Higher moments of other mesoscopic noise sources (2008 – 09)

Pumping of Cooper pairs:Measurement of Berry phase using a Josephson junction detector (2007 – 08)Towards the quantum triangle; improvement of the accuracy of a Cooper pair pump (- 2009)

Coulomb Blockade Thermometer to realize LT temperature scale

Cyclic cooler whose operation is based on Coulomb blockade and energy filtering in tunneling

Cooling out of noise?Heat flows from hot to cold by photon radiation

SNIS: cooling of N by a hot resistor

0 2 4 6 8 10

0.0

0.2

0.4

0.6

0.8

1.0

.

QN / Q

N,o

pt

Te / T

N

.

kBTN = EC = 0.05

Research topics for 2007 - 2009

Thermal effects:Influence of Coulomb blockade on electron cooling (2007)Cyclic electronic refrigerator (2007 - 08)Cooling by thermal noise (2007 – 09)Quantized thermal conductance by photons over mm distances (2008 – 09)

Noise and full counting statistics using a Josephson junction detector:Asymmetry of shot noise of a tunnel junction at high frequencies, comparison to theories (2007)Noise spectroscopy at 1 - 100 GHz frequencies (2007 – 08)Higher moments of other mesoscopic noise sources (2008 – 09)

Pumping of Cooper pairs:Measurement of Berry phase using a Josephson junction detector (2007 – 08)Towards the quantum triangle; improvement of the accuracy of a Cooper pair pump (- 2009)

Coulomb Blockade Thermometer to realize LT temperature scale

Implications of the presented effect

Previously good thermal isolation at low T has been taken for granted (vanishing electron-phonon rate, superconductivity,...)

Increased heat load and noise of micro-bolometers and calorimeters

A way to tune thermal coupling (heat switches, optimization of bolometers)

Another channel to remove heat from dissipative elements, like shunt resistors of SQUIDs at low T

Acts as a mediator of increased decoherence?