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Physics Department, UC Berkeley Materials Sciences Division, LBNL

IRFAN SIDDIQI

2nd Annual E3S Retreat

Berkeley, CA, August 29, 2011

Spin Ensembles

&

Ultrasensitive Spin Readout

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OUTLINE

Operation of Nanosquid magnetometers

RF readout of spin diffusion currents

Resonant readout of diamond NV spin ensembles

2

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JOSEPHSON TUNNEL

JUNCTION

SQUID Superconducting QUantum Interference Device

I0 I0

SQUID

I0 I0 F

Flux tunable nonlinear inductor

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Page 4

Date (Eli Levenson-Falk)

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MICROWAVE READOUT

• Non-dissipative measurement!

• Flux transduction & amplification!

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Page 6

Date

SQUIDOLOGY

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SPIN CURRENTS: TIME DYNAMICS

• Measure RF Voltage • Measure Time Varying Flux

SWITCHING MECHANISM

ENERGY BUDGET

Behin-Aein et. al. , Nature Nano 5, 266 , (2011)

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RESONANT READOUT OF SPIN ENSEMBLES

Date

• Memory

• Quantum Computation

• Classical Computation ?

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BULK DIAMOND NV Meander Resonator (Niobium)

NV Sample

Resonator Chip

2 mm

Bulk NV sample: 1.5x1018 cm-3

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SPIN LINEWIDTH

Sample* Concentration (NVs/cm^3)

Spin Linewidth Coupling

S6 1.5 x 10^18 5.4 MHz 2.8 MHz

S8 5.5 x 10^16 5.6 MHz 136 kHz

B2 ~1.5 x 10^18 8.3 MHz 2.3 MHz

* V. Acosta et al., Phys. Rev. B 80, 1-15 (2009).

= cavity half linewidth C = cavity intrinsic linewidth

gS = spin linewidth D = magnetic field detuning

(

GH

z)

Spin frequency (GHz)

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CLASSICAL LOGIC ?

• Resources for error correction ?

Classical Boolean logic gates with quantum systems N Renaud1 and C Joachim Nanoscience Group and MANA Satellite CEMES/CNRS, 29 rue J Marvig, BP 94347, 31055 Toulouse Cedex, France 1 Present address: Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA

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ACKNOWLEDGEMENTS

Date

Dr. O. Naaman (Northrop-Grumann)

Dr. E. Hoskinson (D-Wave)

Dr. R. Vijay Dr. K. Murch Dr. A. Schmidt

D.H. Slichter E.M. Levenson-Falk N. Henry C. Macklin N. Antler S. Weber

Y.-D. Sun R. Naik A. Narla Z. Minev

Quantum Nanoelectronics Laboratory

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FUTURE WORK

• Measure spin dynamics in diffusion structures

• Investigate spin linewidth in bulk NV structures

- quantify loss due to dipolar coupling

- quantify loss due to bulk defects

- quantify loss due to surface defects

• Fabricate/test resonant structures on diamond substrates

- selective implantation (T. Schenkel, LBNL)

• Investigate other spin systems - Bi:Si (T. Schenkel, LBNL)

- Ruby (D.M. Stamper-Kurn)

Date