Entangling dopant nuclear spins using double quantum dots

Lead Research Organisation: University of St Andrews

Abstract

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Publications

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Cammack H (2018) Coherence protection in coupled quantum systems in Physical Review A

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Lambert N (2017) Microwave irradiation and quasiparticles in a superconducting double dot in Physical Review B

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Lambert N (2016) Quantum capacitance and charge sensing of a superconducting double dot in Applied Physics Letters

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Pica G (2014) Hyperfine Stark effect of shallow donors in silicon in Physical Review B

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Pica G (2016) Quantum gates with donors in germanium in Physical Review B

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Pica G (2014) Exchange coupling between silicon donors: The crucial role of the central cell and mass anisotropy in Physical Review B

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Pica G (2016) Surface code architecture for donors and dots in silicon with imprecise and nonuniform qubit couplings in Physical Review B

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Strathearn A (2017) Efficient real-time path integrals for non-Markovian spin-boson models in New Journal of Physics

 
Description 1. oscillatory coupling between donors in silicon, as a function of separation.

Using an intuitive model we were able to demonstrate that the interaction between the electron spins associated with donors - defect atoms substituted into the silicon lattice, oscillates rapidly with separation of donors. This makes control of this interaction difficult, and this makes building a quantum gate from this interaction challenging.

2. A new architecture for silicon based quantum computing. To overcome the difficulties with oscillatory interactions, we devised a new way to build quantum gates in silicon that is immune to differences in the interaction. These are so-called adiabatic gating strategies. We have proposed a way that these can be used in a large scale "surface code" architecture.

3. We have proposed that a new material - Germanium - may have advantages over silicon in hosting a dopant based quantum computer. This involved using multi-valley effective mass theory to show that the energy splitting donors can be tuned by many orders of magnitude more than donors in Si.
Exploitation Route Our theory blueprint can be used by our experimental partners to build new architectures for quantum gates.
Sectors Digital/Communication/Information Technologies (including Software),Electronics
 
Description Cambridge 
Organisation University of Cambridge
Country United Kingdom 
Sector Academic/University 
PI Contribution Predicted exchange coupling between donors in silicon, and between donors and dots in silicon.
Collaborator Contribution The partners are manufacturing devices that will test the theory and lead to a small scale computing device.
Impact 2014 PRB paper (Pica et al) submitted as outcome was inspired by discussions with partners on donor-dot problem.
Start Year 2012
 
Description Soton 
Organisation University of Southampton
Country United Kingdom 
Sector Academic/University 
PI Contribution Predicted exchange coupling between donors in silicon, and between donors and dots in silicon.
Collaborator Contribution The partners are manufacturing devices that will test the theory and lead to a small scale computing device.
Impact 2014 PRB paper (Pica et al) submitted as outcome was inspired by discussions with partners on donor-dot problem.
Start Year 2013
 
Description UCL 
Organisation University College London
Country United Kingdom 
Sector Academic/University 
PI Contribution Predicted exchange coupling between donors in silicon, and between donors and dots in silicon.
Collaborator Contribution The partners and manufacturing devices that will test the theory and lead to a small scale computing device.
Impact The paper submitted as an outcome was generated following discussions with the partner.
 
Description Silicon Quantum Electronics Workshop 2016 - talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I gave a talk at the international conference, held in Delft Netherlands "Silicon Quantum Electronics Workshop 2016".
Year(s) Of Engagement Activity 2016
URL https://qutech.nl/events/siliconworkshop2016/