John Morton: Controlling spin qubits in silicon in silicon using electric fields and lightExport this event to calendar

Monday, December 8, 2014 — 2:30 PM to 3:30 PM EST

John Morton, University College London

Electron and nuclear spins of donors in silicon are promising candidates for representing quantum bits, with coherence times of up to 3 seconds for the electron spin [1], up to 3 minutes for the neutral donor nuclear spin [2], and 3 hours for the ionized donor nuclear spin [3]. Furthermore, single-shot readout of both the electron spin and nuclear spin have been demonstrated, with measurement fidelities of up to 99.8% [4]. In order to scale up to more complex quantum devices based on donors, it is necessary to find a way to coherently control individual spins (or at least a defined subset of them) within a larger array. We show how global microwave fields combined with (pulsed) DC electric fields can be used to bring different spins in or out of resonance with the control field, using the Stark shift, enabling conditional control. We also show how a combination of applied RF and DC electric fields allows for coherent X- and Z- rotations of the spin [5]. Next, we examine how optically-driven donor-bound exciton transitions can be used to electrically detect of the donor electron spin resonance and investigate issues for adopting this scheme for single spin measurement in silicon nanodevices, including the effects of strain, electric fields, and non-resonant excitation [6]. Finally, I will discuss strategies for scaling up to arrays of multiple coupled dopant spins qubits.

[1] G. Wolfowicz et al., Nature Nanotechnology 8 561 (2013)
[2] M. Stege et al., Science 336 6086 (2012)
[3] K Saeedi et al., Science 342 830 (2013)
[4] J.J. Pla et al., Nature 489 541 (2012); Nature 496 334 (2013)
[5] G. Wolfowicz et al., Phys Rev Lett 113 157601 (2014)
[6] C. C. Lo et al., arXiv:1411.1324 (2014)

Location 
QNC - Quantum Nano Centre
0101
200 University Avenue West

Waterloo, ON N2L 3G1
Canada

S M T W T F S
25
26
27
28
29
30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
2
3
4
5
  1. 2021 (23)
    1. August (1)
    2. May (3)
    3. April (4)
    4. March (5)
    5. February (4)
    6. January (6)
  2. 2020 (31)
    1. December (2)
    2. November (5)
    3. October (4)
    4. September (3)
    5. August (2)
    6. June (4)
    7. April (1)
    8. March (3)
    9. February (5)
    10. January (2)
  3. 2019 (139)
  4. 2018 (142)
  5. 2017 (131)
  6. 2016 (88)
  7. 2015 (82)
  8. 2014 (94)
  9. 2013 (91)
  10. 2012 (122)
  11. 2011 (117)
  12. 2010 (41)
  13. 2009 (4)
  14. 2008 (1)
  15. 2005 (1)
  16. 2004 (3)