Quantum State Preparation Circuit Depth Reduction via Binary Tree Segmentation
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Solution Overview
Problem
In quantum computing, the depth of quantum circuits often becomes excessive due to decoherence and spatial limitations, leading to a degradation into classical circuits, which restricts the interaction between qubits and increases circuit depth, hindering efficient quantum state preparation.
Innovation Solution
A method involving the acquisition and combination of specific quantum gates, such as single qubit flip gates, phase offset gates, SWAP gates, and phase offset gates with path restrictions, to determine a target qubit set and apply these gates in a binary tree structure, reducing circuit depth by iteratively applying these gates until leaf node qubits are reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the depth of quantum circuit is increased to improve quantum state preparation capability, then the quantum circuit will degrade into classic circuit due to decoherence
Solution Approach 1:
The quantum state preparation circuit is divided into multiple shallow sub-circuits operating in layers. Each layer processes a subset of qubits with limited depth, avoiding the need for a single deep circuit. This segmentation maintains quantum coherence while achieving complete state preparation through sequential shallow operations.
Solution Approach 2:
The patent transitions from a vertical depth dimension to a horizontal layer dimension. Instead of increasing circuit depth, the solution adds more layers that operate in parallel on different qubit subsets. This dimensional shift allows comprehensive state preparation without exceeding coherence limits in any single layer.
2Ease of operation
If spatial arrangement of qubits is constrained by physical device, then interaction between qubits is limited and circuit depth increases
Solution Approach 1:
The qubit set is segmented into multiple groups that can be processed in parallel layers. Each layer operates on a manageable subset of qubits that can interact within physical device constraints. This segmentation reduces the interaction complexity within each layer while maintaining overall quantum state preparation capability across all layers.
Solution Approach 2:
The patent employs dynamic qubit grouping where qubits are reassigned to different layers based on interaction requirements. This dynamic reorganization allows flexible adaptation to physical device connectivity constraints, optimizing qubit interactions within each layer's spatial arrangement while maintaining circuit shallow depth.
Data Source
AI summary
The present disclosure relates to a method and apparatus for generating a quantum state preparation circuit, a quantum chip, an electronic device, a storage medium, and a computer program product. The method includes: determining a target qubit set with a binary tree restriction and applying a single qubit flip gate to a first target sub-node qubit; applying a two-qubit phase offset gate between sub-node qubits; applying a two-qubit SWAP gate between the first target sub-node qubit and a second target sub-node qubit; taking the sub-node qubits as the root node qubit and iteratively performing until the sub-node qubits are leaf node qubits; and applying the two-qubit phase offset gate with a path restriction between leaf node qubits and applying a single qubit phase offset gate to the leaf node qubits to obtain a quantum state preparation circuit.