Dark-Mode Qubit Entanglement Without Flux-Tunable Buses
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Solution Overview
Problem
Existing techniques for facilitating entanglement between superconducting qubits consume excessive energy and require large flux-tunable buses, leading to inefficient energy use and increased chip real-estate.
Innovation Solution
The method involves using mode-selective couplers to couple dark modes between superconducting qubits, employing a dark mode excitation pulse sequence that includes a pi-pulse, idle time, and negative pi-pulse to entangle qubits without requiring flux-tunable buses, thereby reducing energy consumption and spatial requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-power microwave drive signals are used to facilitate entanglement between superconducting qubits, then entanglement can be achieved, but excessive energy is consumed and the superconducting qubits are detrimentally affected
Solution Approach 1:
The patent changes the operational parameters by using dark modes (specific quantum states) of the qubits instead of high-power microwave signals. By operating in the dark mode regime and using mode-selective couplers tuned to dark mode frequencies, the system achieves entanglement with significantly reduced power consumption while maintaining entanglement quality
Solution Approach 2:
The patent introduces mode-selective couplers as intermediary elements that mediate the interaction between qubits. These couplers are designed to selectively couple dark modes while decoupling bright modes, enabling entanglement through a controlled intermediary mechanism rather than direct high-power signaling
2Reliability
If large flux-tunable buses are used to facilitate entanglement between superconducting qubits, then entanglement can be achieved, but excessive chip real-estate is consumed
Solution Approach 1:
The patent extracts and eliminates the need for large flux-tunable buses from the system. By using mode-selective couplers that operate with standard fixed-frequency qubits in dark modes, the system removes the requirement for bulky flux-tuning infrastructure, thereby reducing chip real-estate consumption while maintaining entanglement capability
Solution Approach 2:
The patent uses capacitively coupled copies of qubit modes (dark modes) through the mode-selective coupler to achieve entanglement. This approach replicates the entanglement function without requiring the physical presence of large flux-tunable buses, effectively using a simplified copy mechanism
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
This approach enables low-power, spatially-efficient entanglement of superconducting qubits, consuming significantly less energy than traditional methods and eliminating the need for large flux-tunable buses, thus improving quantum computing efficiency.
Implementation Method 1
a middle capacitor pad of the first two-junction transmon qubit can be capacitively coupled to another middle capacitor pad of the second two-junction transmon qubit, such that a dark mode of the first two-junction transmon qubit is coupled to another dark mode of the second two-junction transmon qubit
Implementation Method 2
exciting the dark mode can comprise applying a pi-pulse to the first multi-mode qubit, idling for a predetermined time period after the applying the pi-pulse, and applying a negative pi-pulse to the first multi-mode qubit based on the predetermined time period elapsing
Data Source
AI summary
Systems and techniques that facilitate entanglement via driving dark modes are provided. In various embodiments, a method can comprise accessing a first multi-mode qubit and a second multi-mode qubit. In various cases, the first multi-mode qubit can be coupled to the second multi-mode qubit by a mode-selective coupler. In various aspects, the method can further comprise exciting a dark mode of the first multi-mode qubit. In various cases, the exciting the dark mode can entangle the first multi-mode qubit with the second multi-mode qubit.