Electrical control of a long-lived spin qubit in a Si/SiGe quantum dot.
Erika Kawakami,Pasquale Scarlino,D. R. Ward,F. R. Braakman,F. R. Braakman,Donald E. Savage,Max G. Lagally,Mark Friesen,Susan Coppersmith,Mark A. Eriksson,Lieven M. K. Vandersypen +10 more
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TLDR
In this paper, the authors demonstrate a long-lived single-electron spin qubit driven by resonant microwave electric fields in a transverse magnetic field gradient from a local micromagnet.Abstract:
The electron spin in a silicon-based quantum dot can be controlled electrically for as long as several tens of microseconds, which improves the prospects for quantum information processing based on this type of quantum dot. Nanofabricated quantum bits permit large-scale integration but usually suffer from short coherence times due to interactions with their solid-state environment1. The outstanding challenge is to engineer the environment so that it minimally affects the qubit, but still allows qubit control and scalability. Here, we demonstrate a long-lived single-electron spin qubit in a Si/SiGe quantum dot with all-electrical two-axis control. The spin is driven by resonant microwave electric fields in a transverse magnetic field gradient from a local micromagnet2, and the spin state is read out in the single-shot mode3. Electron spin resonance occurs at two closely spaced frequencies, which we attribute to two valley states. Thanks to the weak hyperfine coupling in silicon, a Ramsey decay timescale of 1 μs is observed, almost two orders of magnitude longer than the intrinsic timescales in GaAs quantum dots4,5, whereas gate operation times are comparable to those reported in GaAs6,7,8. The spin echo decay time is ∼40 μs, both with one and four echo pulses, possibly limited by intervalley scattering. These advances strongly improve the prospects for quantum information processing based on quantum dots.read more
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A two-qubit logic gate in silicon
Menno Veldhorst,C. H. Yang,J. C. C. Hwang,W. Huang,Juan Pablo Dehollain,Juha T. Muhonen,Stephanie Simmons,Arne Laucht,Fay E. Hudson,Kohei M. Itoh,Andrea Morello,Andrew S. Dzurak +11 more
TL;DR: A two-qubit logic gate is presented, which uses single spins in isotopically enriched silicon and is realized by performing single- and two- qubits operations in a quantum dot system using the exchange interaction, as envisaged in the Loss–DiVincenzo proposal.
Journal ArticleDOI
A programmable two-qubit quantum processor in silicon
Thomas F. Watson,S. G. J. Philips,Erika Kawakami,D. R. Ward,Pasquale Scarlino,Menno Veldhorst,Donald E. Savage,Max G. Lagally,Mark Friesen,Susan Coppersmith,Mark A. Eriksson,Lieven M. K. Vandersypen +11 more
TL;DR: A two-qubit quantum processor in a silicon device is demonstrated in this paper, which can perform the Deutsch-Josza algorithm and the Grover search algorithm on demand.
Journal ArticleDOI
A quantum-dot spin qubit with coherence limited by charge noise and fidelity higher than 99.9.
Jun Yoneda,Kenta Takeda,Tomohiro Otsuka,Tomohiro Otsuka,Takashi Nakajima,Matthieu R. Delbecq,Giles Allison,Takumu Honda,Tetsuo Kodera,Shunri Oda,Yusuke Hoshi,Noritaka Usami,Kohei M. Itoh,Seigo Tarucha +13 more
TL;DR: It is revealed that the free-evolution dephasing is caused by charge noise—rather than conventional magnetic noise—as highlighted by a 1/f spectrum extended over seven decades of frequency, offering a promising route to large-scale spin-qubit systems with fault-tolerant controllability.
Journal ArticleDOI
Training Schrödinger’s cat: quantum optimal control
Steffen J. Glaser,Ugo Boscain,Tommaso Calarco,Christiane P. Koch,Walter Köckenberger,Ronnie Kosloff,Ilya Kuprov,Burkhard Luy,Sophie Schirmer,Thomas Schulte-Herbrüggen,Dominique Sugny,Dominique Sugny,Frank K. Wilhelm +12 more
TL;DR: In this communication, state-of-the-art quantum control techniques are reviewed and put into perspective by a consortium of experts in optimal control theory and applications to spectroscopy, imaging, as well as quantum dynamics of closed and open systems.
Journal ArticleDOI
Resonantly driven CNOT gate for electron spins
D. M. Zajac,A. J. Sigillito,Maximilian Russ,F. Borjans,Jacob M. Taylor,Jacob M. Taylor,Guido Burkard,Jason R. Petta +7 more
TL;DR: An efficient resonantly driven CNOT gate for electron spins in silicon is demonstrated and used to create an entangled quantum state called the Bell state with 78% fidelity, which enables multi-qubit algorithms in silicon.
References
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Journal ArticleDOI
Quantum computation with quantum dots
TL;DR: In this paper, a universal set of one-and two-quantum-bit gates for quantum computation using the spin states of coupled single-electron quantum dots is proposed, and the desired operations are effected by the gating of the tunneling barrier between neighboring dots.
Journal ArticleDOI
Coherent manipulation of coupled electron spins in semiconductor quantum dots.
Jason R. Petta,Jason R. Petta,Jason R. Petta,A. C. Johnson,A. C. Johnson,A. C. Johnson,Jacob M. Taylor,Jacob M. Taylor,Jacob M. Taylor,Edward A. Laird,Edward A. Laird,Edward A. Laird,Amir Yacoby,Amir Yacoby,Amir Yacoby,Mikhail D. Lukin,Mikhail D. Lukin,Mikhail D. Lukin,Charles Marcus,Charles Marcus,Charles Marcus,Micah Hanson,Micah Hanson,Micah Hanson,Arthur C. Gossard,Arthur C. Gossard,Arthur C. Gossard +26 more
TL;DR: It is demonstrated coherent control of a quantum two-level system based on two-electron spin states in a double quantum dot, allowing state preparation, coherent manipulation, and projective readout based on rapid electrical control of the exchange interaction.
Journal ArticleDOI
Spins in few-electron quantum dots
TL;DR: In this article, the physics of spins in quantum dots containing one or two electrons, from an experimentalist's viewpoint, are described, and various methods for extracting spin properties from experiment are presented, restricted exclusively to electrical measurements.
Journal ArticleDOI
Hybrid quantum circuits: Superconducting circuits interacting with other quantum systems
TL;DR: Hybrid quantum circuits combine two or more physical systems, with the goal of harnessing the advantages and strengths of the different systems in order to better explore new phenomena and potentially bring about novel quantum technologies as discussed by the authors.
Journal ArticleDOI
Single-shot read-out of an individual electron spin in a quantum dot.
J. M. Elzerman,Ronald Hanson,L. H. Willems van Beveren,B. Witkamp,Lieven M. K. Vandersypen,Leo P. Kouwenhoven +5 more
TL;DR: In this article, the authors demonstrate electrical single-shot measurement of the state of an individual electron spin in a semiconductor quantum dot, using spin-to-charge conversion of a single electron confined in the dot, and detect the single-electron charge using a quantum point contact.
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