Quantum magnonics with a macroscopic ferromagnetic sphere

Transcription

1 Quantum magnonics with a macroscopic ferromagnetic sphere Yasunobu Nakamura Superconducting Quantum Electronics Team Center for Emergent Matter Science (CEMS), RIKEN Research Center for Advanced Science and Technology (RCAST), The University of Tokyo

2 Quantum Information Physics & Engineering UTokyo

3 The magnonists Ryosuke Mori Seiichiro Ishino Yutaka Tabuchi Dany Lachance-Quirion (Sherbrooke) Alto Osada Koji Usami Ryusuke Hisatomi

4 Quantum mechanics in macroscopic scale Quantum state control of collective excitation modes in solids Microscopic Charge Superconductivity Surface plasmon polariton Macroscopic Ordered phase Broken symmetry Spin Photon Atom Magnon Photon Phonon Ferromagnet Lattice order Spatially-extended rigid mode Large transition moment

5 Superconducting qubit nonlinear resonator LC resonator Josephson junction resonator Josephson junction = nonlinear inductor anharmonicity effective two-level system energy inductive energy = confinement potential charging energy = kinetic energy quantized states

6 Quantum interface between microwave and light Quantum repeater Quantum computing network

7 Hybrid quantum systems Superconducting quantum electronics Quantum magnonics Superconducting circuits Surface plasmon polariton Microwave Nonlinearity Quantum nanomechanics Ferromagnet Magnon Nanomechanics Phonon Light Quantum surface acoustics

8 Quantum magnonics

9 Hybrid with paramagnetic spin ensembles Spin ensemble of NV-centers in diamond Kubo et al. PRL 107, (2011). CEA Saclay R. Amsüss et al. PRL (2011). TUWien Zhu et al. Nature 478, 221 (2011). (NTT) Saito et al. Phys. Rev. Lett. 111, (2013). (NTT) Rare-earth doped crystal Optical quantum memory Er:Y 2 SiO 5 Pr:Y 2 SiO 5 Bushev et al. PRB 84, (R) (2011) Karlsruhe Hedges et al. Nature 465, 1052 (2010) Otago

10 Hybrid with ferromagnetic magnons Paramagnet Low spin density cm -3 Spatial mode defined by EM fields Ferromagnet High spin density cm -3 Robust extended spatial mode

11 Two coupled spins 2-magnon 1-magnon 0-magnon

12 N coupled spins 2-magnon 1-magnon 0-magnon cf. Dicke, Phys. Rev. 93, 99 (1954)

13 N coupled spins Effective harmonic oscillator 2-magnon 1-magnon 0-magnon cf. Dicke, Phys. Rev. 93, 99 (1954)

14 Yttrium Iron Garnet (YIG) Ferrimagnetic insulator Narrow FMR line Transparent at infrared High Curie temperature: ~550 K Large spin density: cm -3 Spintronics Microwave oscillators Optical isolators CANDOX Corporation FDK Corporation Kajiwara et al. Nature 2010

15 Hybrid with ferromagnet magnons Kittel mode YIG single crystal B ac B static ~300 mt Microwave resonator 1mm sphere

16 Experimental setup Superconducting coil 1mA YIG Permanent magnet (~300 mt) 1cm Yoke YIG Copper resonator Rectangular TE 101 mode YIG sphere Magnetostatic mode with uniform precession (Kittel mode) Resonator Y. Tabuchi S. Ishino

17 Experimental setup 10 mk plate CAVITY YOKE

18 Magnetic-field dependence Low temperature ~ 10 mk; 1 thermal magnon & photon Microwave power: ~0.9 photons in cavity 0.5-mm sphere Y. Tabuchi et al. PRL 113, (2014)

19 Coupling strength and cooperativity magnon photon Strong coupling condition magnon-polariton Parameter Value Cavity external coupling (κ 1 +κ 2 )/2π 1.6 MHz Cavity intrinsic loss κ int /2π 1.1 MHz Magnon linewidth γ S /2π 1.1 MHz Magnon-photon coupling g m /2π 47 MHz Cooperativity 4g 2 m /γ S (κ c + κ int )

20 Sphere-size dependence of coupling strength Coupling strength per spin Estimation from vacuum fluctuation amplitude Y. Tabuchi et al. PRL 113, (2014)

21 Magnon linewidth vs. temperature ~ K Magnon-phonon (Kasuya-LeCraw) Surface roughness Slowly-relaxing impurity M. Sparks, Ferromagnetic-Relaxation Theory (1964); Data: E. G. Spencer et. al. Phys. Rev. Lett. 3, 32 (1959).

22 Magnon linewidth vs. temperature Coupling to ensemble of two-level systems Red: data cf. superconducting resonator, Martinis 2005 glass physics, Hunklinger ~1980 Theory: J. H. Van Vleck, J. Appl. Phys. 35, 882 (1964).

23 Coupling with a superconducting qubit

24 Inside the cavity SUPERCONDUCTING QUBIT(TRANSMON) YIG CRYSTAL

25 Qubit-magnon coupling Qubit-magnon coupling mediated by virtual photon excitation in cavity

26 Vacuum Rabi splitting qubit Y. Tabuchi et al. Science 349, 405 (2015)

27 Vacuum Rabi oscillations Y. Tabuchi et al. unpublished

28 Magnon-number-resolving spectroscopy D. Lachance-Quirion et al. unpublished TE102 Energy g m ω FFF g q ω q 3 m 2 m 1 m 0 m Magnon Ground state Qubit Excitation

29 (Quantum) optomagnonics

30 Optical detection of magnon excitations Microwave detection Laser Optical detection R. Hisatomi et al. arxiv: ; to appear in PRA

31 Optical detection of magnon excitations at 300 K Magnon Microwave cavity Microwave

32 Optical detection of magnon excitations at 300 K Light Magnon Microwave cavity

33 Coherent microwave generation via magnon Brillouin scattering at 300 K Quantized axis Laser 1550 nm Stimulated Brillouin Scattering AMP Efficiency ~ Magnon number state 10 GHz Difference frequency (GHz) R. Hisatomi et al. arxiv: ; to appear in PRA

34 Cavity optomagnonics See also J. A. Haigh et al. PRA 92, (Cambridge) X. Zhang et al. arxiv: (Yale)

35 Coupling to whispering gallery mode Coupling to whispering gallery mode

36 Photonic chiral modes Chirality in WGM Junge et al. PRL 110, (2013) TUWien Chiral nanophotonic waveguide Petersen et al. Science 346, 67 (2014) TUWien

37 Beyond paraxial approximation dive = E + z E z = 0 E = iie z =0 for plane wave z Spin orbit interactions of light x Review: K. Y. Bliokh et al. Nat. Photo. 9, 796 (2015)

38 Angular momentum selection rule ETE = π ETM = σ+ e, n+1 e, n e, n-1 σ+ σπ σ+ π σ g, n+1 g, n g, n-1 B Blue sideband Red sideband A. Osada et al. arxiv: ; to appear in PRL

39 Non-reciprocal sideband generation TM-input A. Osada et al. arxiv: ; to appear in PRL

40 Non-reciprocal sideband generation TM-input ω TM < ω TE ω TM > ω TE A. Osada et al. arxiv: ; to appear in PRL

41 Role of geometric birefringence Geometrical birefringence TE (m) TM (m) TM(m+1) TM (m-1) TE (m+1) TM input

42 Microwave-light conversion via electro-optical WGM resonator LiNbO 3 Conversion efficiency ~ 10-3 A. Rueda et al. arxiv: (Erlangen)

43 Model π σ +

44 Possible optimization Set all detuning to zero, Ω TM -Ω TE -Ω m =0 x7000 Make a better cavity x3500 Reduce sample volume x100 Conversion efficiency ~ Larger g Verdet const.

45 Conclusions Quantum magnonics with ferromagnet Strong coupling with superconducting qubit Vacuum Rabi oscillations Magnon-number-resolving spectroscopy Optomagnonics Microwave-light conversion Cavity optomagnonics with WGM In progress Manipulation and measurement of non-classical states of magnon mode Optimization of optical coupling ErIG instead of YIG

46 Optical transitions in Yttrium and Erbium iron garnet YIG Fe 3+ ErIG ~400 nm Er 3+ ~1.5 μm ~1.5 μm

47 Optical absorption of REIG 1.5 μm Wood and Remeika, JAP 38, 1038 (1967) Bell Lab

48 Faraday rotation in ErIG 1.5 μm N.I. Tsidaeva, J. Alloys and Compounds 374 (2004) 160