Quantum Optics with Propagating Microwaves in Superconducting Circuits. Io-Chun Hoi 許耀銓

Transcription

1 Quantum Optics with Propagating Microwaves in Superconducting Circuits 許耀銓

2 Outline Motivation: Quantum network Introduction to superconducting circuits Quantum nodes The single-photon router The cross-kerr phase shift The photon-number filter The quantum spectrum analyzer

3 Quantum Network Fig. Kimble, Nature 2008 Quantum node: Generating, processing, routing, storing, reading out quantum information. Quantum channel: Distributing quantum information. Quantum channel Enabling large scale quantum computing and quantum communication.

4 Hybrid Quantum Network Node A Node B Telecom photons to distribute quantum information Quantum node: superconducting circuits Microwave-optical interface is needed R.W. Andrews, et al. Nature Physics 10, 321 (2014) Y. Kubo et al. PRL 105, (2010)

5 Advantages of superconducting circuits E 0 d Atom-light interaction on single photon level 1. Photons and atom interaction can be engineered 2. Standard on-chip fabrication technique 3. Tunable transition energy of the atom 4. Mechanical stable

6 Comparison of the toolboxes Quantum optics Superconducting circuits Optical photons Microwave photons

7 Introduction to Superconducting Circuits

8 Basic Elements of Superconducting Circuits Dissipationless! Josephson Junction: Non-disspative nonlinear inductance L J Capacitance Inductance

9 Basic Elements of Superconducting Circuits Dissipationless! Josephson Junction: Non-disspative nonlinear inductance Tunnel barrier between two superconductors Al L J Al Capacitance Inductance

10 Artificial Atom Based on Quantized Superconducting Circuits LC Harmonic oscillator

11 Artificial Atom Based on Quantized Superconducting Circuits LC Harmonic oscillator

12 Artificial Atom Based on Quantized Superconducting Circuits JJ LC Harmonic oscillator JJ is a nonlinear disspationless inductor Nonlinearity makes the circuit anharmonic and addressable.

13 Artificial Atom Based on Quantized Superconducting Circuits JJ LC Harmonic oscillator JJ is a nonlinear disspationless inductor Nonlinearity makes the circuit anharmonic and addressable.

14 Artificial Atom Based on Quantized Superconducting Circuits f( ) LC Harmonic oscillator Tunable transition frequency by flux through the SQUID loop.

15 Resonant scattering Fig: O. Astafiev, et al. 327, 840 Science (2010)

16 Resonant scattering in 3D space Incoming light Atom/dipole emits light

17 Resonant scattering in 3D space Incoming light Atom/dipole emits light Sum The extinction signal is due to interference G. Wrigge et al. Nature Phys. 4, 60 (2008). M. Tey et al. Nature Phys. 4, 924 (2008). Spatial mode mismatch Fig. from U. Håkanson

18 Resonant scattering in 1D waveguide 1> 0> D.E. Chang et al. Nature Physics 3, 807(2007) Fully coherent: no transmission, perfect reflection.

19 Resonant scattering in 1D waveguide 1> 0> D.E. Chang et al. Nature Physics 3, 807(2007) Fully coherent: no transmission, perfect reflection. Al Point like atom/dipole! l >> d Wavelength of EM field Size of atom elaxation dominated by transmission line um 100 nm O. Astafiev, et al. 327, 840 Science (2010) IoChun, Hoi et al. PRL 107, (2011) Al

20 Resonant scattering in 1D waveguide 1> 0> D.E. Chang et al. Nature Physics 3, 807(2007) Fully coherent: no transmission, perfect reflection. Fig. from E. Olsson & S. M. Nik JJ Al 2nm Point like atom/dipole! l >> d Wavelength of EM field Size of atom elaxation dominated by transmission line um 100 nm O. Astafiev, et al. 327, 840 Science (2010) IoChun, Hoi et al. PRL 107, (2011) Al

21 Transmission and reflection 1> 0> Reflection coefficient Transmission coefficient resonance, low power :Detuning :Relaxation :Pure dephasing Strong interaction limit: Fully coherent.

22 Saturation of transmission Almost full transmission at high power Almost full reflection at low power Nonlinear nature of the atom!

23 Coherent vs Incoherent scattering Sample 2 I.-C. Hoi et al. Phys. Rev. Lett. 108, (2012)

24 Autler-Townes Splitting A. A. Abdumalikov, Jr et al. PRL 104, (2010)

25 The Single-Photon Router By turning on or off the control tone, we can decide which port the input photons go to. I.-C. Hoi et al. PRL 107, (2011)

26 Measuring both T and R simultaneously w Sample 1 Sample 1 Sample 2 Sample 2

27 Photon-Photon interaction via a three-level atom

28 Photon-Photon interaction via a three-level atom Parameters

29 Photon-Photon interaction via a three-level atom Parameters

30 Nonlinear interaction between two microwaves 1us At other flux bias.

31 The Giant Cross-Kerr Phase Shift I.-C. Hoi et al. PRL 111, (2013)

32 The Giant Cross-Kerr Phase Shift I.-C. Hoi et al. PRL 111, (2013) Nonlinear photonic crystal fibres, 0.05 degrees/photon N. Matsuda, et al. Nature Photonics 3,95(2009) V. Venkataraman, et al. Nature Photonics 7,138 (2012)

33 What is the photon statistics of the scattered field?

34 Intensity-Intensity Correlation Single photon source Beam splitter Photon counter Source 2 1 HBT measurement Source Hanbury Brown-Twiss Nature 177, 27 (1956) Second-order correlation function

35 Photon statistics from second order correlation function Coherent state Nonclassical field! ESONN 2010 lecture

36 Photon number filter Poisson probability distibution 320um D.E. Chang et al., Nature Physics 3, 807 (2007)

37 Photon number filter Poisson probability distibution Antibunching! 320um small Bunching! D.E. Chang et al., Nature Physics 3, 807 (2007)

38 Second-order coherence of microwaves Hanbury Brown-Twiss measurement of output state Commercial beam splitter Noise temperature of detection chain is about 7K Noise of two amplifier is uncorrelated. Covariance Gabelli et al. PRL (2004) D. Bozyigit et al. Nature Phys. 7, 154(2011) C. Lang et al. Nature Phys. 9, 345(2013)

39 Transmitted field: Superbunching Statistics

40 Reflected field: Antibunching Statistics 2Tbyte data, computed and averaged over 17 hours. The antibunching behavior reveal quantum nature of light! I.-C. Hoi et al. Phys. Rev. Lett. 108, (2012)

41 Reflected field: Theory

42 An artificial atom in front of a mirror

43 An artificial atom in front of a mirror 50mK Reflection coefficient: p Single ion: J. Eschner Nature, 413, 495 (2001) Changing the normalized distance: Mirror shapes the modes of the vacuum that couple to atom.

44 Changing the spontaneous emission rate Weak drive: Experimental data

45 Changing the spontaneous emission rate Weak drive: Experimental data Atom decoupled from vacuum fluctuations at node.

46 Changing the spontaneous emission rate Weak drive: Experimental data Atom decoupled from vacuum fluctuations at node.

47 pontaneous emission rate as a function of normalized distance 12 G /2p 1 G f /2p [MHz] : relaxation rate of bare atom : phase difference between scattered field from the same atom L /

48 Calibrating atom-field coupling K

49 Probing quantum vacuum fluctuations from spontaneous emission rate k: coupling constant I.-C. Hoi et al. Nature Physics doi: /nphys3484 (2015)

50 Conclusion Quantum node: Generating, processing, routing quantum information. The photon-number filter (Generating) The cross-kerr phase shift (Processing: phase gate) The single-photon router (Routing) The quantum spectrum analyzer (Probing fluctuation) I.-C. Hoi et al. Physical Review Letters, 107, (2011) I.-C. Hoi et al. Physical Review Letters, 108, (2012) I.-C. Hoi et al. Physical Review Letters, 111, (2013) I.-C. Hoi et al. Nature Physics doi: /nphys3484 (2015)

51 Acknowledgements Experimentalists Per Delsing (Chalmers), Chris Wilson (IQC), Arsalan Pourkabirian (Chalmers) Cooperate with Chalmers theorists Göran Johansson, Lars Tornberg, Anton Frisk

52 New lab in NTHU: Postdoc, PhD student, Master student wanted!