Visibility of noisy quantum dot-based measurements of Majorana qubits

Khindanov, Aleksei; Pikulin, Dmitry I.; Karzig, Torsten

doi:10.21468/scipostphys.10.6.127

Cited by 9 publications

(5 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our dephasing calculation, we have chosen the quasistatic approximation also for its conceptual simplicity and widespread use in the literature 49,51 . In real devices, classical or quantum noise often follows a characteristic noise spectrum, e.g., 1/f noise 35,40,46,47,[55][56][57][68][69][70] , Johnson-Nyquist noise, quantum noise of phonons 35,36 , gate-voltage fluctuations 31,35,39,40 , etc. Going beyond the quasistatic approximation by incorporating these frequency-dependent noise features would be an important addition to this work.…”

Section: Discussionmentioning

confidence: 99%

Dephasing of Majorana qubits due to quasistatic disorder

Boross

Pályi

2022

Phys. Rev. B

View full text Add to dashboard Cite

Quantum bits based on Majorana zero modes are expected to be robust against certain noise types, and hence provide a quantum computing platform that is superior to conventional qubits. This robustness is not complete though: imperfections can still lead to qubit decoherence and hence to information loss. In this work, we theoretically study Majorana-qubit dephasing in a minimal model: in a Kitaev chain with quasistatic disorder. Our approach, based on numerics as well as first-order non-degenerate perturbation theory, provides a conceptually simple physical picture and predicts Gaussian dephasing. We show that, as system parameters are varied, the dephasing rate due to disorder oscillates out-of-phase with respect to the oscillating Majorana splitting of the clean system. In our model, first-order dephasing sweet spots are absent if disorder is uncorrelated. We describe the crossover between uncorrelated and highly correlated disorder, and show that dephasing measurements can be used to characterize the disorder correlation length. We expect that our results will be utilized for the design and interpretation of future Majorana-qubit experiments.

show abstract

Section: Discussionmentioning

confidence: 99%

Dephasing of Majorana qubits due to quasistatic disorder

Boross

Pályi

2022

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…In our dephasing calculation, we have chosen the quasistatic approximation also for its conceptual simplicity and widespread use in the literature 49,51 . In real devices, classical or quantum noise often follows a characteristic noise spectrum, e.g., 1/f noise 35,40,46,47,[55][56][57][67][68][69] , Johnson-Nyquist noise, quantum noise of phonons 35,36 , gate-voltage fluctuations 31,35,39,40 , etc. Going beyond the quasistatic approximation by incorporating these frequency-dependent noise features would be an important addition to this work.…”

Section: Discussionmentioning

confidence: 99%

Dephasing of Majorana qubits due to quasistatic disorder

Boross,

Pályi

2021

Preprint

View full text Add to dashboard Cite

Quantum bits based on Majorana zero modes are expected to be robust against certain noise types, and hence provide a quantum computing platform that is superior to conventional qubits. This robustness is not complete though: imperfections can still lead to qubit decoherence and hence to information loss. In this work, we theoretically study Majorana-qubit dephasing in a minimal model: in a Kitaev chain with quasistatic disorder. Our approach, based on numerics as well as first-order non-degenerate perturbation theory, provides a conceptually simple physical picture and predicts Gaussian dephasing. We show that, as system parameters are varied, the dephasing rate due to disorder oscillates out-of-phase with respect to the oscillating minigap of the clean system. In our model, first-order dephasing sweet spots are absent, a feature that can be used to characterize the spatial structure of noise in a dephasing experiment. We expect that our results will be utilized for the design and interpretation of future Majorana-qubit experiments.

show abstract

“…The key difference to previous works [23,31,32,34,69] is that here, we do not assume the dot to be described by a single electronic level. We instead consider a more realistic multi-orbital scenario with M dot states j entering the dynamics.…”

Section: A Model and Readout Principlementioning

confidence: 93%

“…2(f), or when noise sources such as quasiparticle poisoning limit the measurement time. We emphasize, however, that this requires a challenging tuning of the phase φ with low parameter noise [69], as well as a good control of the initial dot state. The latter also involves gate operations faster than the typical decay rate Γ = gλ, as needs to be varied from some large initial detuning | | λ that strongly favors an empty or fully occupied dot level.…”

Section: Visibility In the Presence Of Charge Sensormentioning

confidence: 99%

Multilevel effects in quantum dot based parity-to-charge conversion of Majorana box qubits

et al. 2021

View full text Add to dashboard Cite

Quantum-dot based parity-to-charge conversion is a promising method for reading out quantum information encoded nonlocally into pairs of Majorana zero modes. To obtain a sizable parity-tocharge visibility, it is crucial to tune the relative phase of the tunnel couplings between the dot and the Majorana modes appropriately. However, in the presence of multiple quasi-degenerate dot orbitals, it is in general not experimentally feasible to tune all couplings individually. This paper shows that such configurations could make it difficult to avoid a destructive multi-orbital interference effect that substantially reduces the read-out visibility. We analyze this effect using a Lindblad quantum master equation. This exposes how the experimentally relevant system parameters enhance or suppress the visibility when strong charging energy, measurement dissipation and, most importantly, multi-orbital interference is accounted for. In particular, we find that an intermediate-time readout could mitigate some of the interference-related visibility reductions affecting the stationary limit.

show abstract

Visibility of noisy quantum dot-based measurements of Majorana qubits

Cited by 9 publications

References 53 publications

Dephasing of Majorana qubits due to quasistatic disorder

Dephasing of Majorana qubits due to quasistatic disorder

Dephasing of Majorana qubits due to quasistatic disorder

Multilevel effects in quantum dot based parity-to-charge conversion of Majorana box qubits

Contact Info

Product

Resources

About