Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Bulletin of the American Physical Society

Cavity-based readout and control of Majorana qubits

Thomas B. Smith, Arne L. Grimsmo, Stephen D. Bartlett, Andrew C. Doherty

Published Mar 4, 2019• 0 citations
OpenAlex

Related papers

Majorana qubit readout using parametric modulation of light-matter coupling

Arne L. Grimsmo, Alexandre Blais, Karl D. Petersson

Bulletin of the American Physical Society•Mar 5, 2018•0 citations

Four-Majorana qubit with charge readout: Dynamics and decoherence

Tommy Li, W. A. Coish, Michael Hell +2 more

We present a theoretical analysis of a Majorana-based qubit consisting of two topological superconducting islands connected via a Josephson junction. The qubit is operated by electrostatic gates which control the coupling of two of the four Majorana zero modes. At the end of the operation, readout is performed in the charge basis. Even though the operations are not topologically protected, the proposed experiment can potentially shed light on the coherence of the parity degree of freedom in Majorana devices and serve as a first step towards topological Majorana qubits. We discuss in detail the charge-stability diagram and its use for characterizing the parameters of the devices, including the overlap of the Majorana edge states. We describe the multilevel spectral properties of the system and present a detailed study of its controlled coherent oscillations, as well as decoherence resulting from coupling to a non-Markovian environment. In particular, we study a gate-controlled protocol where conversion between Coulomb-blockade and transmon regimes generates coherent oscillations of the qubit state due to the overlap of Majorana modes. We show that, in addition to fluctuations of the Majorana coupling, considerable measurement errors may be accumulated during the conversion intervals when electrostatic fluctuations in the superconducting islands are present. These results are also relevant for several proposed implementations of topological qubits which rely on readout based on charge detection.

arXiv:1807.05839•Physical review. B./Physical review. B•Nov 5, 2018•25 citations

Majorana qubit readout using longitudinal qubit-resonator interaction

Arne L. Grimsmo, Thomas B. Smith

We propose a quantum nondemolition Majorana qubit readout protocol based on parametric modulation of a longitudinal interaction between a pair of Majorana bound states and a resonator. The interaction can be modulated through microwave-frequency gate voltage or flux control of a tunable tunnel barrier. The qubit-resonator coupling is quantum nondemolition to exponential accuracy, a property inherited from the topological nature of the Majorana zero modes. The same mechanism as used for single-qubit readout can also be extended to perform multiqubit measurements and be used to enact long-range entangling gates.

arXiv:1809.07776•Physical review. B./Physical review. B•Jun 19, 2019•21 citations

Probing Majorana edge states with a qubit

Chang-Yu Hou, Fabian Hassler, Johan Nilsson +1 more

Bulletin of the American Physical Society•Mar 24, 2011•0 citations

Dispersive Readout of Majorana Qubits

Thomas B. Smith, Maja C. Cassidy, D. J. Reilly +2 more

We analyze a readout scheme for Majorana qubits based on dispersive coupling to a resonator.We consider two variants of Majorana qubits: the Majorana transmon and the Majorana box qubit.In both cases, the qubit-resonator interaction can produce sizeable dispersive shifts in the megahertz range for reasonable system parameters, allowing for submicrosecond readout with high fidelity.For Majorana transmons, the light-matter interaction used for readout manifestly conserves Majorana parity, which leads to a notion of quantum nondemolition (QND) readout that is stronger than for conventional charge qubits.In contrast, Majorana box qubits only recover an approximately QND readout mechanism in the dispersive limit where the resonator detuning is large.We also compare dispersive readout to longitudinal readout for the Majorana box qubit.We show that the latter gives faster and higher fidelity readout for reasonable parameters, while having the additional advantage of being manifestly QND, and so may prove to be a better readout mechanism for these systems.

arXiv:2009.00027•PRX Quantum•Nov 10, 2020•32 citations

Randomized Benchmarking of Majorana Based Qubits

Alan Tran, Bela Bauer, Parsa Bonderson +1 more

Bulletin of the American Physical Society•Mar 8, 2019•0 citations
We present a theoretical analysis of a Majorana-based qubit consisting of two topological superconducting islands connected via a Josephson junction. The qubit is operated by electrostatic gates which control the coupling of two of the four Majorana zero modes. At the end of the operation, readout is performed in the charge basis. Even though the operations are not topologically protected, the proposed experiment can potentially shed light on the coherence of the parity degree of freedom in Majorana devices and serve as a first step towards topological Majorana qubits. We discuss in detail the charge-stability diagram and its use for characterizing the parameters of the devices, including the overlap of the Majorana edge states. We describe the multilevel spectral properties of the system and present a detailed study of its controlled coherent oscillations, as well as decoherence resulting from coupling to a non-Markovian environment. In particular, we study a gate-controlled protocol where conversion between Coulomb-blockade and transmon regimes generates coherent oscillations of the qubit state due to the overlap of Majorana modes. We show that, in addition to fluctuations of the Majorana coupling, considerable measurement errors may be accumulated during the conversion intervals when electrostatic fluctuations in the superconducting islands are present. These results are also relevant for several proposed implementations of topological qubits which rely on readout based on charge detection.
We propose a quantum nondemolition Majorana qubit readout protocol based on parametric modulation of a longitudinal interaction between a pair of Majorana bound states and a resonator. The interaction can be modulated through microwave-frequency gate voltage or flux control of a tunable tunnel barrier. The qubit-resonator coupling is quantum nondemolition to exponential accuracy, a property inherited from the topological nature of the Majorana zero modes. The same mechanism as used for single-qubit readout can also be extended to perform multiqubit measurements and be used to enact long-range entangling gates.
We analyze a readout scheme for Majorana qubits based on dispersive coupling to a resonator.We consider two variants of Majorana qubits: the Majorana transmon and the Majorana box qubit.In both cases, the qubit-resonator interaction can produce sizeable dispersive shifts in the megahertz range for reasonable system parameters, allowing for submicrosecond readout with high fidelity.For Majorana transmons, the light-matter interaction used for readout manifestly conserves Majorana parity, which leads to a notion of quantum nondemolition (QND) readout that is stronger than for conventional charge qubits.In contrast, Majorana box qubits only recover an approximately QND readout mechanism in the dispersive limit where the resonator detuning is large.We also compare dispersive readout to longitudinal readout for the Majorana box qubit.We show that the latter gives faster and higher fidelity readout for reasonable parameters, while having the additional advantage of being manifestly QND, and so may prove to be a better readout mechanism for these systems.