Measuring heat current and its fluctuations in superconducting quantum circuits

Transcription

1 Measuring heat current and its fluctuations in superconducting quantum circuits Bayan Karimi QTF Centre of Excellence, Department of Applied Physics, Aalto University, Finland Supervisor: Jukka P. Pekola Collaborators: Alberto Ronzani, Jorden Senior, Azat Gubaydullin, Yu-Cheng Chang, Joonas T. Peltonen, Tuomas Tuukkanen, Elsa Mannila, Fredrik Brange, Peter Samuelsson, Rosario Fazio, Michele Campisi, and Erik Aurell. Open Questions on Energy Transport & Conversion in Nanoscale Quantum Systems, Marseille, Nov. 2018

2 Quantum Otto refrigerator 1 E H = ħω H EE C H = = ħω ħω C H 1 B. Karimi and J. P. Pekola, Otto refrigerator based on a superconducting qubit: classical and quantum performance, Phys. Rev. B 94, (2016). Editor s suggestion 2

3 QHV principle of expected operation R H R C Source Drain 3

4 Superconducting qubit as a heat valve 0,6 3 mm RESERVOIR AND THERMOMETERS P 1->2 (fw) 0,4 0,2 0,0 LC /2 = 8 GHz T 1 = 0.3 K T 2 = 0.1 K g = 0.03 Q = 3 (red), 10 (black), 30 (blue) /2 (GHz) 10 mm TRANSMON QUBIT A. Ronzani, B. Karimi, J. Senior, Y. C. Chang, J. T. Peltonen, C. D. Chen, and J. P. Pekola, Nature Physics 14, 991 (2018) B. Karimi, J. Pekola, M. Campisi, and R. Fazio, Quantum Science and Technology 2, (2017). Timofeev et al., PRL 102, (2009), M. Partanen et al., Nature Physics 12, 460 (2016). 4

5 Thermal model of the QHV P D = G el ph T 5

6 NIS-thermometry Probes electron temperature of N electrode (and not of S!) Feshchenko et al., Phys. Rev. Appl. 4, (2015). 6

7 Spectroscopy to determine circuit parameters Two tone spectroscopy RF feedline diagnostic source drain f r = 5.39 GHz g = g = a = r = f qubit /f r 7

8 Theory vs. experiment: non-hamiltonian R H γ Q -1 g g γ Q -1 R C gq << 1 reservoir resonator SQUID resonator reservoir 8

9 Theory vs. experiment: non-hamiltonian R H γ Q -1 g g γ Q -1 R C gq << 1 Q~3 reservoir resonator SQUID resonator reservoir Cooling at distance of 4 mm by mw photons QT60, September 2018, Finland 9

10 Theory vs. experiment: quasi-hamiltonian R H γ Q -1 g g γ Q -1 R C gq >> 1 reservoir resonator SQUID resonator reservoir 10

11 Theory vs. experiment: quasi-hamiltonian R H γ Q -1 g g γ Q -1 R C gq ~ 1 Q~20 reservoir resonator SQUID resonator reservoir 11

12 Recent results on an asymmetric device 2,0 T_bath=140 mk 1,6 Estimated DT (mk) 1,2 0,8 0,4 0,0-0,4 100 aw T S 200 mk T S 100 mk -0,8 Jorden Senior et al, in preparation I coil (ma) 12

13 How to measure time dependent heat current? E C, T+DT Our goal: Single microwave photon detection E = 100 mev (10 8 times smaller energy!) T b G th D. McCammon et al., 1984 Single x-ray photon detection E = 6 kev Energy resolution: Thermometry! 13

14 Fast NIS thermometry on electrons Read-out at 600 MHz of a NIS junction, 10 MHz bandwidth S 21 (db) V th (mv) T (mk) mv 150 mv 153 mv 156 mv 159 mv 162 mv 165 mv 168 mv S 21 (db) S. Gasparinetti et al., Phys. Rev. Applied 3, (2015); B. Karimi and J. Pekola, arxiv: D. Schmidt et al., Appl. Phys. Lett. 83, 1002 (2003). K.L.Viisanen & J.P.Pekola, Phys. Rev. B, 97, (2018). 14

15 ZBA based thermometry B. Karimi and J. Pekola, arxiv: , Physical Review Applied (in press) N S S I Proximity NIS junction - non-invasive - operates at low temperature O.-P. Saira et al., Phys. Rev. Appl. 6, (2016); J. Govenius et al., PRL 117, (2016) 15

16 I S (pa) 100 Optimization of ZBA thermometer Supercurrent increases with decreased distance of the contact N d S I S 10 I S = I 0 e d ξ d (nm) 16

17 Noise of heat current and equilibrium temperature fluctuations Noise of electrical current, i.e. Johnson-Nyquist noise Fluctuation-dissipation theorem for heat current Low frequency noise: Finite frequencies (classical): 17

18 Preliminary results on temperature fluctuations Thermometer S T 1/2 (mk /Hz 1/2 ) g= g= g= g= T (mk) Equilibrium noise B. Karimi et al., in preparation 18

19 Measuring time dependent temperature Thermometer V inj <T > (mk) V inj (mv) B. Karimi et al., in preparation Non-equilibrium noise 60 μk Hz F. Brange, P. Samuelsson, B. Karimi,J. P. Pekola.arXiv:

20 Calorimetry for measuring mw photons Requirements for calorimetry on single microwave quantum level: photon source artificial atom temperature readout electronics E absorber G th J. Pekola, P. Solinas, A. Shnirman, and D. V. Averin., NJP 15, (2013); F. Brange, P. Samuelsson, B. Karimi, J. P. Pekola., arxiv:

21 Jukka Pekola Alberto Ronzani Jorden Senior Azat Gubaydullin Yu-Cheng Chang Joonas Peltonen

22 Summary Presented a set-up for cqtd Experiments on QHV Fast non-invasive thermometry ZBA Preliminary experiments on heat current and temperature fluctuations 22

23 Coupled qubits, Better operation! B. Karimi, J. Pekola, M. Campisi, and R. Fazio, Quantum Science and Technology 2, (2017). P C (x10 4 ) ,2 0,0 0,2 q 5

24 Quantum Thermodynamics Conference QTD2019 Espoo (Helsinki) - Finland June Abstract submission deadline: 15 February 2019