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Three-spin qubits under the influence of tunneling noise

Maximilian Russ, Guido Burkard

Bulletin of the American Physical SocietyMar 14, 20170 citations

Spin decoherence in a two-qubit CPHASE gate: the critical role of tunneling noise

Peihao Huang, Neil M. Zimmerman, Garnett W. Bryant

Abstract Rapid progress in semiconductor spin qubits has enabled experimental demonstrations of a two-qubit logic gate. Understanding spin decoherence in a two-qubit logic gate is necessary for optimal qubit operation. We study spin decoherence due to 1/f charge noise for two electrons in a double quantum dot used for a two-qubit controlled-phase gate. In contrast to the usual belief, spin decoherence can be dominated by the tunneling noise from 1/f charge noise instead of the detuning noise. Tunneling noise can dominate because the effect of tunneling noise on the spin qubit is first order in the charge admixture; while the effect of the detuning noise is only second order. The different orders of contributions result in different detuning dependence of the decoherence, which provides a way to identify the noise source. We find that decoherence in a recent two-qubit experiment was dominated by the tunneling noise from 1/f charge noise. The results illustrate the importance of considering tunneling noise to design optimal operation of spin qubits.Abstract Rapid progress in semiconductor spin qubits has enabled experimental demonstrations of a two-qubit logic gate. Understanding spin decoherence in a two-qubit logic gate is necessary for optimal qubit operation. We study spin decoherence due to 1/f charge noise for two electrons in a double quantum dot used for a two-qubit controlled-phase gate. In contrast to the usual belief, spin decoherence can be dominated by the tunneling noise from 1/f charge noise instead of the detuning noise. Tunneling noise can dominate because the effect of tunneling noise on the spin qubit is first order in the charge admixture; while the effect of the detuning noise is only second order. The different orders of contributions result in different detuning dependence of the decoherence, which provides a way to identify the noise source. We find that decoherence in a recent two-qubit experiment was dominated by the tunneling noise from 1/f charge noise. The results illustrate the importance of considering tunneling noise to design optimal operation of spin qubits.

arXiv:1803.01062npj Quantum InformationNov 21, 201822 citations

Proposed spin-qubit controlled-not gate robust against noisy coupling

J. P. Kestner, S. Das Sarma

We propose an implementation of the two-qubit gate in a quantum dot spin qubit system which is immune to charge noise problems. Our proposed implementation, if it could be realized in a physical system, would have the advantage of being robust against uncertainties and fluctuations in the tunnel coupling and barrier gate voltage pulse area. The key idea is to introduce an auxiliary dot and use an analog to the stimulated Raman adiabatic passage pulse sequence in three-level atomic systems, often referred to in the context of electron transport in quantum dot systems as Coherent Tunneling by Adiabatic Passage. Spin-dependent tunneling opens the possibility of performing two-qubit gate operations by this method.We propose an implementation of the two-qubit gate in a quantum dot spin qubit system which is immune to charge noise problems. Our proposed implementation, if it could be realized in a physical system, would have the advantage of being robust against uncertainties and fluctuations in the tunnel coupling and barrier gate voltage pulse area. The key idea is to introduce an auxiliary dot and use an analog to the stimulated Raman adiabatic passage pulse sequence in three-level atomic systems, often referred to in the context of electron transport in quantum dot systems as Coherent Tunneling by Adiabatic Passage. Spin-dependent tunneling opens the possibility of performing two-qubit gate operations by this method.

arXiv:1103.1379Physical Review AJul 18, 20118 citations

Decoherence during two-qubit gates

M. J. Storcz, Frank Hellmann, Calin Hrelescu +1 more

Verhandlungen der Deutschen Physikalischen GesellschaftJan 1, 20050 citations

Decoherence of coupled spin qubits due to charge fluctuations

Guy Ramon, Xuedong Hu

Bulletin of the American Physical SocietyMar 13, 20080 citations

Strong Coupling of Spin Qubits to a Transmission Line Resonator

Pei-Qing Jin, Michael Marthaler, Alexander Shnirman +1 more

We propose a mechanism for coupling spin qubits formed in double quantum dots to a superconducting transmission line resonator. Coupling the resonator to the gate controlling the interdot tunneling creates a spin qubit-resonator interaction with a strength of tens of MHz. This mechanism allows operating the system at a symmetry point where decoherence due to charge noise is minimized. The transmission line can serve as the shuttle, allowing for fast two-qubit operations including the generation of qubit-qubit entanglement and the implementation of a controlled-phase gate.We propose a mechanism for coupling spin qubits formed in double quantum dots to a superconducting transmission line resonator. Coupling the resonator to the gate controlling the interdot tunneling creates a spin qubit-resonator interaction with a strength of tens of MHz. This mechanism allows operating the system at a symmetry point where decoherence due to charge noise is minimized. The transmission line can serve as the shuttle, allowing for fast two-qubit operations including the generation of qubit-qubit entanglement and the implementation of a controlled-phase gate.

arXiv:1112.0869Physical Review LettersMay 11, 201279 citations

Critical role of tunneling noise on spin decoherence in a two-qubit gate

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