Towards quantum simulator based on nuclear spins at room temperature

Transcription

1 Towards quantum simulator based on nuclear spins at room temperature B. Naydenov and F. Jelezko C. Müller, Xi Kong, T. Unden, L. McGuinness J.-M. Cai and M.B. Plenio Institute of Theoretical Physics, Uni Ulm In collaboration with: S. Pezzagna and J. Meijer, Uni Leipzig A. Stacey M. Markham, E6 Ltd. J. Du, Hafei

2 Slide 2 Outline Controlling single spins nitrogen-vacancy center (NV) in diamond NMR with single spin sensitivity Approaches towards a quantum simulator using fluorine spins Speeding up 2D NMR experiments Summary and Outlook

3 Slide 3 Quantum simulator on the diamond surface Diamond 111-surface F-F (long range dipole) interaction (6.8 khz nearest neighbor) Fluorographene Diamond 100-surface Cai, Retzker, Jelezko, Plenio. Nature Physics 9, 168 (2013)

4 Slide 4 Single defects in diamond Nitrogen Vacancy 3E E=hc/638n m Color centers in diamond. Point defects NV, NE8, TR12, SiV and a long list Single defects in a crystalline matrix. Atomic emitter can be shrunk to nm sized Photostablity electrons don t escape! 3A vacancies 800 C 10 µm Production with ion implantation N+ ions Meijer et al., APL 87, (2005)

5 Slide 5 Spin properties of NV ms 1 0 mw Fluorescence, a. u. 3E Optically Detected Magnetic Resonance ES 1A 1 3A GS (ground state) H ZFS DS z2 E S x2 S y MW frequency, MHz Single spin manipulation Spin polarization in ground state ms=0 by and read out at room optical pumping temperature! Encoding ms=0 and ms=1 as bright A. Gruber et al., Science 276, 2012 (1997) and dark state F. Jelezko, et.al, Phys. Rev. Lett. 92, (2004)

6 Slide 6 Coherent spin manipulation Laser 532 nm initialize ms=0 3 s read-out MW pulse Excited-state MW pulse duration ( s) MW effective 2-level system by Zeeman splitting

7 Pulse Sequences Free Induction Decay (FID) and Hahn echo Spin locking

8 Slide 8 NMR with few nuclear spins

9 Slide 9 Single spin spectrometer using NV The basics idea

10 Slide 10 The NMR Spectrometer

11 Slide 11 Diamond spin as NMR sensor Use of NV centers as near field antenna for NMR, ESR with nanoscale resolution e- spin sensor nn ne Nuclear spins nn n e Classical noise First detection of external nuclear spins With nanoscale resolution Staudacher et al., Science, 339, 561 (2013) Mamin et al., Science 339, 557 (2013)

12 Slide 12 The Pulse Sequence - XY8-N Quantum Lock-In Amplifier T. Gullion et al., JMR 89, 479 (1990) S. Kotler et al. Nature 473, 61 (2011)

13 Slide 13 Nuclear Spins inside the diamond Nuclear spins in a frozen core, strong interaction Kolkowitz, PRL 109, (2012) Zhao, N. et al. Nature Nanotechnology 7 (2012) Taminiau, T. H. et al. PRL 109, (2012) nn ne ne 1 T2 e e- spin sensor nn ne Nuclear spins Single nuclear spins resolved, frequency shift in NV field gradient

14 Slide 14 Creating shallow NVs Implantation of 2.5 kev N+ ions Average depth 4 nm % 12C diamond. erage distance between 13C > 4nm Low dose N+ implant 3x108 ion/cm2 Average distance between Nitrogen dopants > 500 nm

15 Slide 15 Mapping the NVs Identification of shallow NV centers via spin noise technique Distance from the surface 1.9 nm for most shallow NV, T2 < 10 µs NV 1: Distance = 2.2 nm Signal = H spins NV 6: Distance = 1.92 nm Signal = H spins NV 7: Distance = 2.2 nm Signal = H spins

16 Slide 16 Strong coupling regime Polarization not required Utilize NV magnetic gradient to isolate individual nuclei based on their hyperfine shift Also image position relative to NV center Quantum interaction vs classical magnetic field measurement Strongest 29Si-29Si interaction (0.17 khz) Coupling to NV 2 khz

17 Slide Detection of Si nuclei in SiO2 Signal agrees with numerical detection of 5 to 10 29Si nuclei

18 Slide 18 Contributing nuclear spins About 7 29Si nuclei give 70 % of the signal

19 Slide 19 Single nuclear spin sensitivity 5 nm3 volume NV Contributing nuclei

20 Slide 20 2D NMR Correlation Spectroscopy (COSY) Polar. /2 /2 /2 Readout

21 Slide 21 Frequency Domain full data set

22 Slide 22 Frequency Domain less data 20 % of the data 10 % of the data

23 Slide 23 Shallow NVs - problems Implantation with E 1impl =2.5keV T2 measurement T2 = 5,6 μs Implantation with E 2impl =1.25keV Implantation with E 2impl =1.25keV

24 Slide 24 Increase of Creation Yield by Surface Termination CF4 Plasma: Yield: 0.1% Yield: 0.5%

25 Slide 25 Oxygen Termination O2 Plasma: Oxygen Terminated Surface : NVs : 1739 Yield : % Fluorine Terminated Surface: NVs : 1960 Yield : %

26 Slide 26 Stability and Properties of Implanted NVs T2 measurement before Plasma: T2 = 5,6 μs T2 measurement after Fluorination: T2 = 5,7 μs C. Osterkamp et al. APL 103, (2013)

27 Slide 27 Very nice but it did not work! We could not detect the fluorine nuclear spin

28 Slide 28 New Fluorination Method Using SF6 plasma No oxygen peak!

29 Slide 29 Fluorinated graphene alternative? Optical picture of diamond surface with graphene Appl. Phys. A 82, (2006)

30 Slide 30 Conclusion and Outlook We can detect few nuclear spins at room temperature! Different implementations of a small nuclear spin cluster Implementation of matrix completion

31 Slide 31 Thank you!

32 CPMG (XY) sensing Shallow NV suffer from surface noise (T2 < 10 µs) Use of high order dynamical decoupling (XY 8-N) H 0 L I Z H1 ( L A) I Z BI X Two different nuclear spin quantization axes U 0 exp ih 0 exp ih1 exp ih 0 U 0 exp ih1 exp ih 0 exp ih1 The nuclear spin is rotated differently depending on the electron subspace Polarization of nuclear spins is not required

33 Distance Measurement