Two-Mode Quantum Coupler With Equal Exchange Coupling for ZZ Cancellation
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Solution Overview
Problem
Existing quantum couplers fail to effectively suppress ZZ interactions between qubits, leading to reduced fidelity and increased errors in quantum operations, as they do not utilize two-junction qubits as fixed-frequency couplers or flux-tunable transmon qubits efficiently.
Innovation Solution
A device comprising a coupler that operates in two oscillating modes, with equal exchange coupling between superconducting qubits and the coupler's oscillating modes, suppressing ZZ interactions by detuning the coupler from these modes to facilitate reduced quantum gate errors and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If qubits are coupled via a bus, then quantum operations can be performed, but residual ZZ interactions cause frequency shifts and reduce fidelity
Solution Approach 1:
The patent introduces a coupler as an intermediary component between qubits that mediates their interaction. The coupler is designed with specific oscillating modes that enable controlled coupling while suppressing unwanted ZZ interactions, acting as a mediator that filters harmful direct interactions between qubits.
Solution Approach 2:
The patent employs parameter changes by tuning the oscillating modes of the coupler to specific frequencies. By adjusting the coupling parameters and detuning the coupler modes from qubit frequencies, the system achieves suppression of ZZ interactions while maintaining desired quantum operations.
2Adaptability or versatility
If flux-tunable transmon qubits are used, then coupling can be tuned, but ZZ interactions are not effectively suppressed
Solution Approach 1:
The patent segments the coupling function by separating it from the qubits themselves and placing it in a dedicated coupler component. This segmentation allows the coupler to be independently optimized with specific oscillating modes that suppress ZZ interactions, while qubits maintain their flux-tunable properties for adaptability.
Solution Approach 2:
The patent implements dynamic control through the coupler's oscillating modes, which can be tuned and detuned as needed. The system dynamically adjusts the coupling strength and characteristics by controlling the coupler's resonant modes, enabling both tunability and suppression of harmful interactions.
3Adaptability or versatility
If two-junction qubits are used for tunable coupling, then multiple qubits can be encoded, but they do not function as fixed-frequency couplers
Solution Approach 1:
The patent achieves universality by having the two-junction qubits serve multiple functions: they act as both computational qubits (for encoding information) and as part of the coupling mechanism (through their interaction with the coupler's oscillating modes). This multi-functionality eliminates the need for separate fixed-frequency coupler components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves reduced quantum gate errors, increased speed, and improved fidelity of quantum operations by suppressing ZZ interactions, enabling the development of logical qubits and scalable quantum computers.
Implementation Method 1
The device can comprise a first Josephson junction and a second Josephson junction
Implementation Method 2
a first oscillating mode and a second oscillating mode that are indicative of symmetric and antisymmetric combinations of excitations associated with a Josephson Junction and a flux controlled qubit device of the coupler device
Data Source
AI summary
Devices and/or computer-implemented methods to facilitate ZZ cancellation between qubits are provided. According to an embodiment, a device can comprise a coupler device that operates in a first oscillating mode and a second oscillating mode. The device can further comprise a first superconducting qubit coupled to the coupler device based on a first oscillating mode structure corresponding to the first oscillating mode and based on a second oscillating mode structure corresponding to the second oscillating mode. The device can further comprise a second superconducting qubit coupled to the coupler device based on the first oscillating mode structure and the second oscillating mode structure.