A Boolean-Phase swapping gate is introduced for quantum generality and cost-effectiveness, which is termed the "p-SWAP gate", where p is a customizable phase difference for a set of swapped qubits and 0 <= p <= ${\pm π}$ radians. The generality of the p-SWAP gate is proposed for quantum Phase oracles requiring a desirable p for a set of swapped qubits, as well as for quantum Boolean oracles when p is ignored. The cost-effectiveness of the p-SWAP gate comes from the lower quantum cost and depth for its final synthesized (transpiled) quantum circuit into a quantum computer, as compared to the standard SWAP gate. In general, the standard SWAP gate is constructed using three Feynman (CNOT) gates, while our p-SWAP gate only utilizes two CNOT gates. In this paper, the desirability of p is geometrically chosen using our proposed Bloch sphere approach, without using any matrices multiplication and unitary representations. After transpilation, the final transpiled p-SWAP gate has approximately 23% quantum cost reduction and 26% depth minimization than those of the final transpiled standard SWAP gate.
A Boolean-Phase swapping gate is introduced for quantum generality and cost-effectiveness, which is termed the "p-SWAP gate", where p is a customizable phase difference for a set of swapped qubits and 0 <= p <= ±π radians. The generality of the p-SWAP gate is proposed for quantum Phase oracles requiring a desirable p for a set of swapped qubits, as well as for quantum Boolean oracles when p is ignored. The cost-effectiveness of the p-SWAP gate comes from the lower quantum cost and depth for its final synthesized (transpiled) quantum circuit into a quantum computer, as compared to the standard SWAP gate. In general, the standard SWAP gate is constructed using three Feynman (CNOT) gates, while our p-SWAP gate only utilizes two CNOT gates. In this paper, the desirability of p is geometrically chosen using our proposed Bloch sphere approach, without using any matrices multiplication and unitary representations. After transpilation, the final transpiled p-SWAP gate has approximately 23% quantum cost reduction and 26% depth minimization than those of the final transpiled standard SWAP gate.
A new Boolean-Phase swapping gate is presented with improved quantum generality and cost-effectiveness. Our swapping gate is termed the "p-SWAP gate", where p is the phase difference selected for a set of swapped qubits. The phase p is expressed in radians and −π≤ p ≤+π. The generality of p-SWAP gate is demonstrated for Phase applications for selected values of p and for Boolean applications when the value of p is ignored. The cost-effectiveness of p-SWAP gate follows from the lower quantum cost and depth of its final realized (transpiled) quantum circuit, when compared to the standard SWAP gate composed of three Feynman (CNOT) gates. Specifically, our presented p-SWAP gate utilizes only two CNOT gates. The quantum circuit of the p-SWAP gate is visually designed using our previously developed Bloch sphere approach. Experimentally, after transpilation for an IBM quantum computer, the transpiled p-SWAP gate shows an approximate 23% quantum cost reduction and an approximate 26% depth minimization compared to the transpiled standard SWAP gate.
The Bloch sphere is a geometrical 3D sphere that visualizes the states of a qubit after a series of quantum gates are applied to it. In quantum computing, the Bloch sphere is mainly used as a geometrical visualization (and verification) tool. On the other hand, in this protocol, we introduce the Bloch sphere as a geometrical design tool for building cost-effective quantum gates based on their rotational quantum operations in the XY, XZ, and/or YZ planes, which are the 2D circular projections along the axes of the Bloch sphere. Collectively, the Bloch sphere and its projectional planes are termed the Bloch sphere approach (BSA). With the BSA, various generic and cost-effective quantum gates and libraries are designed for IBM quantum computers, using the symmetrical and semi-symmetrical structures [1-5], Clifford+T gates, and IBM native "basis" gates ( , , , and ). Our designed generic and cost-effective quantum gates and libraries are listed as follows, where 2 n 5 qubits. Quantum libraries: GALA-n [3, 6] and CALA-n [4, 7], which have become part of the IBM Qiskit ecosystem [8] n-bit Toffoli gate [2-4] n-bit Boolean gates (AND, NAND, OR, NOR, Implication, and Inhibition) [3, 4] n-bit controlled- ( ) and controlled- ( ) gates [3, 4] n-bit Fredkin gate [3, 4] n-bit Miller gate [3, 4] Boolean-Phase SWAP gate: p-SWAP [4, 5] Because the quantum operations of all IBM native gates mainly rotate around the X-axis and Z-axis of the Bloch sphere, the XY-plane of the Bloch sphere is utilized here for the BSA. However, the BSA can also be utilized to build generic and cost-effective quantum gates for other quantum computers, e.g., Intel, Google, and Rigetti, using other projectional planes of the Bloch sphere, e.g., the XZ and YZ planes, based on the supported native gates for such quantum computers. Therefore, in this protocol, we introduce the BSA as a generic and open geometrical framework for prospective quantum computing research and building interesting and innovative quantum gates and circuits.
The Bloch sphere is a geometrical 3D sphere that visualizes the states of a qubit after a series of quantum gates are applied to it. In quantum computing, the Bloch sphere is mainly used as a geometrical visualization (and verification) tool. On the other hand, in this protocol, we introduce the Bloch sphere as a geometrical design tool for building cost-effective quantum gates based on their rotational quantum operations in the XY, XZ, and/or YZ planes, which are the 2D circular projections of the Bloch sphere. Collectively, the Bloch sphere and its planes are termed the Bloch sphere approach (BSA). With the BSA, various generic and cost-effective quantum gates and libraries are designed for IBM quantum computers, using the symmetrical and semi-symmetrical structures [1-5], Clifford+T gates, and IBM native "basis" gates ( , , , and ). Our designed generic and cost-effective quantum gates and libraries are listed as follows, where 2 n 5 qubits. Quantum libraries: GALA-n [3, 6] and CALA-n [4, 7], which have become part of the IBM Qiskit ecosystem [8] n-bit Toffoli gate [2-4] n-bit Boolean gates (AND, NAND, OR, NOR, implication, and inhibition) [3, 4] n-bit controlled- ( ) and controlled- ( ) gates [3, 4] n-bit Fredkin gate [3, 4] n-bit Miller gate [3, 4] Boolean-Phase SWAP gate: p-SWAP [4, 5] Because the quantum operations of all IBM native gates mainly rotate around the X-axis and Z-axis of the Bloch sphere, the XY-plane of the Bloch sphere is utilized here for the BSA. However, the BSA can also be utilized to build generic and cost-effective quantum gates for other quantum computers, e.g., Intel, Google, and Rigetti, using other projectional planes of the Bloch sphere, i.e., the XZ and YZ planes, based on the supported native gates for such quantum computers. Therefore, in this protocol, we introduce the BSA as a generic and open geometrical framework for prospective quantum computing research for building interesting and innovative quantum gates and circuits.
The conventional design technique of any n-bit quantum gate is mainly achieved using unitary matrices multiplication, where n >= 2 and 1 <= m <= n-1 for m target qubits and n-m control qubits. These matrices represent quantum rotations by an n-bit quantum gate. For a quantum designer, such a conventional technique requires extensive computational time and effort, which may generate an n-bit quantum gate with a too high quantum cost. The Bloch sphere is only utilized as a visualization tool to verify the conventional design correctness for quantum rotations by a quantum gate. In contrast, this paper introduces a new concept of using the Bloch sphere as a "geometrical design tool" to build cost-effective n-bit quantum gates with lower quantum costs. This concept is termed the "Bloch sphere approach (BSA)". In BSA, a cost-effective n-bit quantum gate is built without using any unitary matrices multiplication. Instead, the quantum rotations for such a gate are visually selected using the geometrical planar intersections of the Bloch sphere. The BSA can efficiently map m targets among n-m controls for an n-bit quantum gate, to satisfy the limited layout connectivity for the physical neighboring qubits of a quantum computer. Experimentally, n-bit quantum gates built using the BSA always have lower quantum costs than those for such gates built using the conventional quantum design techniques.
A cost-effective n-bit Toffoli gate is proposed to be realized (or transpiled) based on the layouts (linear, T-like, and I-like) and the number of n physical qubits for IBM quantum computers. This proposed gate is termed the "layout-aware n-bit Toffoli gate". The layout-aware n-bit Toffoli gate is designed using the visual approach of the Bloch sphere, from the visual representations of the rotational quantum operations for IBM native gates. In this paper, we also proposed a new formula for the quantum cost, which calculates the total number of native gates, the crossing connections, and the depth of the final transpiled quantum circuit. This formula is termed the "transpilation quantum cost". After transpilation, our proposed layout-aware n-bit Toffoli gate always has a much lower transpilation quantum cost than that of the conventional n-bit Toffoli gate, where 3 <= n <= 7 qubits, for different IBM quantum computers.
The conventional design technique of any n-bit quantum gate is mainly achieved using the multiplication of unitary matrices for control qubits and target qubits, where and .These matrices represent quantum rotations by an n-bit quantum gate.For a quantum designer, such a conventional technique requires extensive computational time and effort, which may generate an n-bit quantum gate with too high quantum cost.In general, the Bloch sphere is only utilized as a visualization tool to verify the conventional design correctness for quantum rotations by a quantum gate.In contrast, this paper introduces a new concept of using the Bloch sphere as a "geometrical design tool" to build cost-effective n-bit quantum gates with lower quantum costs.This concept is termed the "Bloch sphere approach (BSA)."In BSA, a cost-effective n-bit quantum gate is built without using any multiplication of unitary matrices.Instead, the quantum rotations for such a gate are visually selected using the geometrical planar intersections of the Bloch sphere.The BSA can efficiently map m targets among controls for an n-bit quantum gate to satisfy the limited layout connectivity for the physical neighboring qubits of a superconducting quantum computer.Experimentally, n-bit quantum gates built using the BSA always have lower quantum costs than those for such gates built using the conventional quantum design techniques, by utilizing the same transpilation settings and the restricted layout connectivity of a real IBM superconducting quantum computer, where qubits.