Scaling up single atom spin qubits in silicon

by Andrea Morello

at Physics Colloquium

Tue, 28 Nov 2017, 15:30
Nanotechnology institute building (#51) room 15

Abstract

The modern information era is built on silicon nanoelectronic devices The future quantum information era might be built on silicon too if we succeed in controlling the interactions between individual spins hosted in silicon nanostructures Spins in silicon constitute excellent solid state qubits because of the weak spin orbit coupling and the possibility to remove nuclear spins from the environment through 28Si isotopic enrichment Substitutional 31P atoms in silicon behave approximately like hydrogen in vacuum providing two spin 1 2 qubits the donor bound electron and the 31P nucleus that can be coherently controlled 1 2 read out in single shot 2 3 and are naturally coupled through the hyperfine interaction In isotopically enriched 28Si these single atom qubits have demonstrated outstanding coherence times up to 35 seconds for the nuclear spin 4 and 1 qubit gate fidelities well above 99 9 for both the electron and the nucleus 5 The hyperfine coupling provides a built in interaction to entangle the two qubits within one atom The combined initialization control and readout fidelities result in a violation of Bell s inequality with S 2 70 a record value for solid state qubits 6 Despite being identical atomic systems 31P atoms can be addressed individually by locally modifying the hyperfine interaction through electrostatic gating 7 Multi qubit logic gates can be mediated either by the exchange interaction 8 or by electric dipole coupling 9 Scaling up beyond a single atom presents formidable challenges but provides a pathway to building quantum processors that are compatible with standard semiconductor fabrication and retain a nanometric footprint important for truly large scale quantum computers 1 J J Pla et al Nature 489 541 2012 2 J J Pla et al Nature 496 334 2013 3 A Morello et al Nature 467 687 2010 4 J T Muhonen et al Nature Nanotech 9 986 2014 5 J T Muhonen et al J Phys : Condens Matt 27 154205 2015 6 J P Dehollain et al Nature Nanotech 11 242 2016 7 A Laucht et al Science Advances 1 e1500022 2015 8 R Kalra et al Phys Rev X 4 021044 2014 9 G Tosi et al Nature Communications 8:450 2017

Created on 13-11-2017 by Bar Lev, Yevgeny (ybarlev)
Updaded on 13-11-2017 by Bar Lev, Yevgeny (ybarlev)