Frequency-Tunable Coupler for Faster Multi-Qubit Entangling Gates
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Solution Overview
Problem
Superconducting qubits have a finite coherence time, limiting the duration for state preparation and algorithmic manipulation, which restricts the number of qubits that can be used in quantum computing due to the increasing time required for entangling multiple qubits, leading to errors and scalability issues.
Innovation Solution
A method and device using fixed-frequency quantum circuits coupled with a frequency-tunable coupler, where the coupler's frequency is concomitantly modulated at multiple frequencies to drive energy transitions between connected pairs of states, enabling the creation of entangled states as a superposition of multiple states in shorter times, leveraging high-coherence fixed-frequency qubits for efficient multi-qubit entangling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequential two-qubit gate operations are used to entangle multiple qubits, then entanglement can be achieved with high fidelity, but the state preparation time increases with the number of qubits, exceeding the coherence time
Solution Approach 1:
The patent combines multiple two-qubit gate operations into a single multi-qubit entangling gate operation. By coupling n qubits simultaneously to a frequency-tunable coupler and modulating the coupler frequency at multiple frequencies corresponding to different qubit pairs, the system achieves entanglement of all n qubits in one step rather than through sequential operations, thereby reducing state preparation time while maintaining high fidelity
Solution Approach 2:
The patent employs dynamic frequency modulation of the coupler element to enable selective coupling between different qubit pairs. By concomitantly modulating the coupler frequency at m frequencies (where m ≥ 2), the system dynamically controls which qubit pairs interact, allowing parallel entangling operations across multiple qubit pairs within the coherence time
2Quantity of substance
If the number of qubits is increased to enhance computational power, then more complex quantum algorithms can be executed, but the state preparation time increases proportionally, limiting scalability
Solution Approach 1:
The patent merges the functionality of multiple sequential two-qubit gates into a single multi-qubit gate that operates on all n qubits simultaneously. This parallel operation approach allows the system to scale to larger numbers of qubits without proportionally increasing the state preparation time, as all qubits are entangled in one collective operation rather than through sequential pairwise operations
Solution Approach 2:
The frequency-tunable coupler serves multiple functions simultaneously: it couples different pairs of qubits, enables multiple transition frequencies, and supports parallel entangling operations. This multi-functionality allows the same hardware component to handle entanglement generation across all n qubits, enabling scalable quantum computing without requiring separate dedicated components for each qubit pair
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 allows for rapid and high-fidelity generation of highly entangled multi-qubit states, reducing state preparation time, enabling quantum computers to perform with fewer errors and scale to a larger number of qubits, while maintaining high coherence and fidelity.
Implementation Method 1
the frequency-tunable coupler element, by modulating its frequency concomitantly at a first frequency and a second frequency
Implementation Method 2
wherein said first frequency corresponds to a difference of energy between a first pair of quantum states and wherein said second frequency corresponds to a difference of energy between a second pair of quantum states
Data Source
AI summary
A quantum processing comprises n fixed-frequency quantum circuits of distinct frequencies, where n≥3. The device further comprises a frequency-tunable coupler, designed in such a manner that its frequency can be concomitantly modulated at m frequencies, where m≥2, and wherein said m frequencies correspond, each, to a difference of energy between a respective pair of quantum states spanned by the quantum circuits. The quantum circuits are, each, coupled to the tunable coupler. The method may rely on modulating the frequency of the tunable coupler concomitantly at said m frequencies. This, for example, is done so as to drive m energy transitions between connected pairs of states spanned by the quantum circuits and achieve an entangled state of the quantum circuits as a superposition of l states spanned by the quantum circuits, l≥m.