Dephasing of Solid-State Qubits at Optimal Points

Makhlin, Yuriy; Shnirman, Alexander

doi:10.1103/physrevlett.92.178301

Cited by 149 publications

(248 citation statements)

References 14 publications

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“…This would be unrealistic until future when fabrication process is greatly advanced. The fluctuation of sizes would lead to that of interaction amplitude between qubits and a measurement apparatus, and that of the applied gate bias, in addition to the effect of randomly distributed background traps 10,11 . Note that even a roughness of the order of 1Å at interfaces affects current characteristics in advanced LSI technologies as shown in Ref.…”

mentioning

confidence: 99%

“…Thus, the measurement is an important interaction with the environment for qubits. The charge qubit is a two-level system 13 controlled by gate electrodes 10,14 , and constituted from coupled QDs where one excess electron is inserted, assuming there is one energy level in each QD. The detector discussed here is a quantum point contact (QPC) in the tunneling region depicted in Fig.1.…”

mentioning

confidence: 99%

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Decoherence-free states for charge qubits under local nonuniformity

Tanamoto

Fujita

2005

Phys. Rev. B

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We analyze the robustness of decoherence-free (DF) subspace and subsystem in charge qubits, when difference from the collective decoherence measurement condition is large (∼5%) in the long time period, which is applicable for solid-state qubits using as a quantum memory. We solve master equations of up to four charge qubits and a detector as a quantum point contact (QPC). We show that robustness of DF states is strongly affected by local non-uniformities. We also discuss the possible two-qubit logical states by exactly solving the master equations.

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mentioning

confidence: 99%

mentioning

confidence: 99%

Decoherence-free states for charge qubits under local nonuniformity

Tanamoto

Fujita

2005

Phys. Rev. B

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“…There are three types of these qubits: phase [5]; flux [6]; and charge [5,7,14]. These types of qubits have a great scalability, advanced capabilities for managing states, relatively high coherence time.…”

Section: Interaction With An External Fieldmentioning

confidence: 99%

Error analysis in circuits building at the quantum computing platform IBM Quantum Experience

Samsonov¹

2017

Nanosystems: Phys. Chem. Math.

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There are many quantum computing systems, some of which are still being developed today. To develop quantum calculation systems, IBM provides access to the 5-qubit quantum computer 'IBM Quantum Experience'. Quantum computers must deal with the loss of information due to environmental disturbances. Quantum systems cannot be completely isolated. Noise can be a cause of different errors in the quantum circuits. In this work, we observe distortions in quantum circuits and investigate the noise stability of different quantum gates. We investigate a method for calculating the quantum state of the superconducting qubit, used in 'IBM Quantum Experience', after an interaction with a quantum operator.

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“…9 In this paper, we quantify the effect of sweet spots on gate fidelities by performing theoretical simulations of pulsed gate operations in an exchange-only qubit. The sweet spot in this device occurs at the symmetry point shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Characterizing gate operations near the sweet spot of an exchange-only qubit

et al. 2015

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Optimal working points or "sweet spots" have arisen as an important tool for mitigating charge noise in quantum dot logical spin qubits. The exchange-only qubit provides an ideal system for studying this effect because Z rotations are performed directly at the sweet spot, while X rotations are not. Here for the first time we quantify the ability of the sweet spot to mitigate charge noise by treating X and Z rotations on an equal footing. Specifically, we optimize X rotations and determine an upper bound on their fidelity. We find that sweet spots offer a fidelity improvement factor of at least 20 for typical GaAs devices, and more for Si devices.

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Dephasing of Solid-State Qubits at Optimal Points

Cited by 149 publications

References 14 publications

Decoherence-free states for charge qubits under local nonuniformity

Decoherence-free states for charge qubits under local nonuniformity

Error analysis in circuits building at the quantum computing platform IBM Quantum Experience

Characterizing gate operations near the sweet spot of an exchange-only qubit

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