Distributed quantum computation has garnered immense attention in the noisy intermediate-scale quantum (NISQ) era, where each computational node necessitates fewer qubits and quantum gates. In this paper, we focus on a generalized search problem involving multiple targets within an unordered database and propose a Distributed Exact Generalized Grover’s Algorithm (DEGGA) to address this challenge by decomposing it into arbitrary t components, where 2 ⩽ t ⩽ n. Specifically, (1) our algorithm ensures accuracy, with a theoretical probability of identifying the target states at 100%; (2) if the number of targets is fixed, the pivotal factor influencing the circuit depth of DEGGA is the partitioning strategy, rather than the magnitude of n; (3) the maximum number of qubits required by our method at a single node is max (n0, n1, …, nt−1), where nj represents the number of qubits for the jth node and satisfies <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\sum\nolimits_{j=0}^{t-1}n_{j}=n$</EquationSource> <EquationSource Format="MATHML"><math display="block"> <msubsup> <mo movablelimits="false">∑</mo> <mrow> <mi>j</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>t</mi> <mo>−</mo> <mn>1</mn> </mrow> </msubsup> <msub> <mi>n</mi> <mrow> <mi>j</mi> </mrow> </msub> <mo>=</mo> <mi>n</mi> </math></EquationSource> </InlineEquation>, eliminating the need for auxiliary qubits; (4) we elucidate the resolutions (two-node and three-node) of a particular generalized search issue incorporating two goal strings (000000 and 111111) by applying DEGGA. The feasibility and effectiveness of our suggested approach is further demonstrated by executing the quantum circuits on MindSpore Quantum (a quantum simulation software). Eventually, through the decomposition of multi-qubit gates, DEGGA diminishes the utilization of quantum gates by 90.7% and decreases the circuit depth by 91.3% in comparison to the modified Grover’s algorithm by Long. It is increasingly evident that distributed quantum algorithms offer augmented practicality.

Distributed exact generalized Grover’s algorithm

期刊论文
发表日期：

2026年1月31日

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Xu Zhou,
Xusheng Xu,
Shenggen Zheng,
Le Luo

摘要

Distributed quantum computation has garnered immense attention in the noisy intermediate-scale quantum (NISQ) era, where each computational node necessitates fewer qubits and quantum gates. In this paper, we focus on a generalized search problem involving multiple targets within an unordered database and propose a Distributed Exact Generalized Grover’s Algorithm (DEGGA) to address this challenge by decomposing it into arbitrary t components, where 2 ⩽ t ⩽ n. Specifically, (1) our algorithm ensures accuracy, with a theoretical probability of identifying the target states at 100%; (2) if the number of targets is fixed, the pivotal factor influencing the circuit depth of DEGGA is the partitioning strategy, rather than the magnitude of n; (3) the maximum number of qubits required by our method at a single node is max (n₀, n₁, …, n_t−1), where n_j represents the number of qubits for the jth node and satisfies $\sum\nolimits_{j=0}^{t-1}n_{j}=n$ $\sum_{j = 0}^{t - 1} n_{j} = n$ , eliminating the need for auxiliary qubits; (4) we elucidate the resolutions (two-node and three-node) of a particular generalized search issue incorporating two goal strings (000000 and 111111) by applying DEGGA. The feasibility and effectiveness of our suggested approach is further demonstrated by executing the quantum circuits on MindSpore Quantum (a quantum simulation software). Eventually, through the decomposition of multi-qubit gates, DEGGA diminishes the utilization of quantum gates by 90.7% and decreases the circuit depth by 91.3% in comparison to the modified Grover’s algorithm by Long. It is increasingly evident that distributed quantum algorithms offer augmented practicality.