Challenge the future

DelftUniversity ofTechnology

Phase-slip Oscillator

Alina M. Hriscu, Yuli V. Nazarov

Kavli Institute for Nanoscience, TU Delft

Acknowledgements: Hans Mooij, Kees Harmans,

Ad Verbruggen, Tomoko Fuse

2Quantum Engineering of States and Devices, 06.06.2010, Obergurgl

A.M. Hriscu, Phase-slip oscillator

(quantum) Phase-slips

• Superconducting wires : d≈10 nm• resistance below Tc

• Thermally-activated phase-slips• slip of the phase => "phase-

slip“

• Quantum phase-slips • proposed for qu-bit• coherent!• not experimentally confirmed yet

Introduction

• Our idea: other means of sensitive measurements?

Mooij and Harmans (2005)

Schön (2000)

tim

e

3Quantum Engineering of States and Devices, 06.06.2010, Obergurgl

A.M. Hriscu, Phase-slip oscillator

Phase-slip oscillator

Damped LC oscillator + phase-slip wireΓ : OSCILLATOR

QUALITY

n=…

n=1

n=0

ES=0ES≠0

4Quantum Engineering of States and Devices, 06.06.2010, Obergurgl

A.M. Hriscu, Phase-slip oscillator

Unusual non-linearities

Unusual non-linearities

Gate voltage sensitivity

• More interesting problem

phase-slip amplitudecharge

• Correction to the energy levels

5Quantum Engineering of States and Devices, 06.06.2010, Obergurgl

A.M. Hriscu, Phase-slip oscillator

Intermezzo: Non-linearities

Duffing oscillator Phase-slip oscillator Usual Unusual

Resonance spectrum

Non-linearities2n

?

1/ 4

cos(2 )4cos( / )S

nE q e

n

6Quantum Engineering of States and Devices, 06.06.2010, Obergurgl

A.M. Hriscu, Phase-slip oscillator

Phase-slip Oscillator: Results

Lorentzian “Corkscrew”

NO non-linearities UNUSUAL non-linearities

I. SemiclassicalN

=

<n

>

Num

ber

of

ph

oto

ns

• Multiple solutions • Enables experimental detection

0

Detuning

7Quantum Engineering of States and Devices, 06.06.2010, Obergurgl

A.M. Hriscu, Phase-slip oscillator

Phase-slip Oscillator: Results

1 semiclassical metastable state 1 SINGLE quantum state

• Confirms existence of meta-stable states• Hysteresis

• Long life-times Pure states • Slow switching

II. Quantum

YES!

Semiclassical prediction

Quantum : loops

n

?

8Quantum Engineering of States and Devices, 06.06.2010, Obergurgl

A.M. Hriscu, Phase-slip oscillator

Phase-slip oscillator

• Novel system in superconducting electronics

• Unusual non-linearities• At small number of photons• Tunable with• Usable in many applications

•ultrasensitive measurements, quantum manipulation, etc.

• Detection of quantum phase-slip• Oscillatory dependence on gate voltage• Measurement of responses of the oscillator

Conclusions

http://arxiv.org/abs/0912.3699 (Submitted to PRL)