Entanglement distillation between solid-state quantum network nodes

Transcription

1 Entanglement distillation between solid-state quantum network nodes Norbert Kalb, A. A. Reiserer, P. C. Humphreys, J. J. W. Bakermans, S. J. Kamerling, N. H. Nickerson, S. C. Benjamin, D. J. Twitchen, M. Markham, R. Hanson

2 Our ambition: a first quantum internet Collaboration between experimental physicists, theorists, material scientists, engineering support Blind & distributed QC DI-QKD Metrology applications

3 A diamond-based quantum network Communication qubits to generate remote entanglement Robust memory qubits for storage High-fidelity control and readout for processing and error correction

4 Why NV centres? Optical interface Long coherence times ~1 s Nature 477 (2011) Nuclear spin quantum register unpublished Remote entanglement Nature Nat. Nano. 484 (2012), 9 (2014); Nature PRX Phys. (2016); 9 (2013) arxiv: (2015) Nat. Commun. 7 (2016) Nature 497 (2013); Science 345(2014); Nature 526 (2015); Scient. Rep. 6, (2016) Many related works by Stuttgart, Harvard, Chicago, Ulm,

5 Diamond networks: A to-do list Optical cavities: expect rate x1000 Telecom wavelength conversion Zaske et al. PRL 109, (2012) Maletinsky/Warburton PRX 7, (2017) This talk This talk

6 Wiring up the ideal quantum internet

7 Wiring up the ideal quantum internet Click! APD CLICK

8 Wiring up the real quantum internet APD CLICK APD CLICK Phase dependent Mixed state due to loss

9 Overcoming imperfections: The distillery

10 Distillation Phase dependent Mixed state We use: Campbell & Benjamin, PRL 101, (2008) Initial protocols: Bennett et al., PRL (1996); Deutsch et al., PRL (1996)

11 Distillation Photonic experiments Trapped ions only post-selected local distillation within 1 trap J.-W. Pan et al., Nature 423, 417 (2003) R. Reichle et al., Nature 443, 838 (2006) Nuclear spin quantum register Remote entanglement

12 Always-on interactions Entanglement generation sequence N 0 Nuclear spin quantum register Remote entanglement

13 Always-on interactions State dependent frequency of the nuclear spin memory 0 Entanglement generation sequence N 0 Nuclear spin quantum register Remote entanglement

14 Always-on interactions State dependent frequency of the nuclear spin memory 1 Entanglement generation sequence N 0 Nuclear spin quantum register Remote entanglement

15 Always-on interactions State dependent frequency of the nuclear spin memory 1 Entanglement generation sequence N 0 1 Reiserer*, NK*, et al., PRX 6, (2016)

16 Always-on interactions State dependent frequency of the nuclear spin memory 1 Entanglement generation sequence N 0 Reinitialization: Complicated and probabilistic evolution NV occupies spin states randomly Causes nuclear dephasing Reiserer*, NK*, et al., PRX 6, (2016) 1

17 Always-on interactions State dependent frequency of the nuclear spin memory 1 Entanglement generation sequence N 0 This talk 1 Reiserer*, NK*, et al., PRX 6, (2016)

18 N α + β Node A Node B

19 Distillation experiment Science 356, 928 (2017) 1 Generate remote entangled state Communication qubit (NV e - spin) 2 Swap to memories Generate another remote entangled state 3 Memory qubit ( 13 C nuclear spin) 2m 4 Distillation via local operations 2m

20 Distillation experiment Science 356, 928 (2017)

21 Distillation experiment Science 356, 928 (2017) 1 Generate remote entangled state Communication qubit (NV e - spin) 2 Swap to memories Generate another remote entangled state 3 Memory qubit ( 13 C nuclear spin) 4 Distillation via local operations Raw state is of the form: 1 α Ψ φ ± Ψ φ ± +α 0,0 0,0 α

22 Distillation experiment Science 356, 928 (2017) 1 Generate remote entangled state Communication qubit (NV e - spin) 2 Swap to memories Generate another remote entangled state 3 Memory qubit ( 13 C nuclear spin) 4 Distillation via local operations Raw state is of the form: 1 α Ψ φ ± Ψ φ ± +α 0,0 0,0 α

23 Distillation experiment Science 356, 928 (2017) 1 Generate remote entangled state Communication qubit (NV e - spin) 2 Swap to memories Generate another remote entangled state 3 Memory qubit ( 13 C nuclear spin) 4 Distillation via local operations Raw state is of the form: 1 α Ψ φ ± Ψ φ ± +α 0,0 0,0 α

24 Distillation experiment Science 356, 928 (2017) 1 Generate remote entangled state Communication qubit (NV e - spin) 2 Swap to memories Generate another remote entangled state 3 Memory qubit ( 13 C nuclear spin) 4 Distillation via local operations Raw state is of the form: 1 α Ψ φ ± Ψ φ ± +α 0,0 0,0 α

25 Distillation experiment Science 356, 928 (2017) 1 Generate remote entangled state Communication qubit (NV e - spin) 2 Swap to memories Generate another remote entangled state 3 Memory qubit ( 13 C nuclear spin) 4 Distillation via local operations Raw state is of the form: 1 α Ψ φ ± Ψ φ ± +α 0,0 0,0 α

26 Deterministic entanglement generation Measure and correct internal phase Vastly increased entangling rate (40 Hz)! 1 α Ψ 0 ± Ψ 0 ± +α 0,0 0,0 P. Humphreys, NK et al., in preparation

27 α NK et al., Science 356, 928 (2017)

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