Quantum Circuit Decomposition Using Ancilla Qubit Allocation
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Solution Overview
Problem
The inefficiency of quantum computation due to the conversion of non-basic quantum gates into equivalent circuits with a large number of gates, and the limited duration of qubits' quantum states, necessitate a method to minimize the number of quantum gates in quantum circuits.
Innovation Solution
A method to decompose complex quantum gates like Ck-NOT gates into equivalent circuits using C2-NOT gates, optimizing the number of ancilla qubits and managing clean and dirty qubits to reduce the overall quantum gate count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-basic quantum gates are converted into equivalent circuits using basic quantum gates, then the quantum circuit can be executed on standard quantum computers, but the number of quantum gates increases which reduces computation efficiency
Solution Approach 1:
The patent applies parameter changes by optimizing the number of ancilla qubits used in the equivalent circuit transformation. By carefully selecting and managing the number of auxiliary qubits (k-2 for Ck-NOT gates), the system achieves efficient conversion while minimizing the increase in gate count, thus resolving the contradiction between compatibility and efficiency
2Reliability
If the number of quantum gates in a quantum circuit is reduced, then the success probability of quantum computation increases, but the ability to implement complex quantum operations decreases
Solution Approach 1:
The patent segments complex quantum gates (Ck-NOT gates with k≥3) into sequences of basic quantum gates (C2-NOT gates and single-qubit gates). This segmentation allows the system to maintain the ability to implement complex operations while using a manageable number of gates, thereby improving success probability without sacrificing functionality
Solution Approach 2:
The patent introduces ancilla qubits as intermediary elements to facilitate the transformation of complex gates into basic gates. These ancilla qubits serve as mediators that enable the decomposition process while minimizing their impact on the overall circuit size and gate count
3Ease of manufacture
If more ancilla qubits are used in the equivalent circuit transformation, then the conversion of quantum gates becomes more straightforward, but the total number of qubits and gates increases
Solution Approach 1:
The patent optimizes the parameter of ancilla qubit count by using exactly k-2 ancilla qubits for Ck-NOT gate transformations. This optimized parameter selection makes the transformation process straightforward while minimizing the total number of qubits and gates required, resolving the contradiction between ease of transformation and quantity of components
Data Source
AI summary
A quantum circuit design support apparatus determines the number of control qubits for each of one or more third quantum gates corresponding respectively to one or more third qubits that have a predetermined value before the gate operation of a first quantum gate that flips the value of the target qubit when all control qubits are 1, and the number of control qubits for a second quantum gate so that a predetermined relationship is satisfied. The quantum circuit design support apparatus generates a second quantum circuit including the third quantum gates, each using first qubits equal in number to the determined number of control qubits as the control qubits and a third qubit as the target qubit, and the second quantum gate using a first qubit not used in the third quantum gates and the third qubits as the control qubits and the second qubit as the target qubit.