System and method for generating quantum circuits

A computer-implemented method of generating a quantum circuit from a Hamiltonian using a parameterised operator including excitation operators to represent an excitation of a reference state, wherein the method includes determining multi-qubit Pauli operators from each excitation operator, wherein the method comprises:

• partitioning the Pauli operators into mutually commuting sets and sequencing the Pauli operators by set;
• generating Pauli gadgets from the Pauli operators by Trotterization, wherein the Pauli gadgets have the same sequencing by set as the Pauli operators;
• diagonalising each set of Pauli gadgets to convert the Pauli gadgets into phase gadgets;
• and
• transforming the phase gadgets into one- and two-qubit native gates to generate the quantum circuit;
• wherein the Hamiltonian corresponds to a molecular structure.

A non-transitory, computer-readable medium in which is stored a computer program that is executable on computing hardware for implementing a method to generate a quantum circuit from a Unitary Coupled Cluster (UCC) Ansatz, wherein the Ansatz represents an excitation of a reference state by a parameterised operator including excitation operators, wherein the Ansatz includes multi-qubit Pauli operators that are determined from each excitation operator, and wherein the program code is executable to implement a method comprising:

• partitioning the Pauli operators into mutually commuting sets and sequencing the Pauli operators by set;
• generating Pauli gadgets from the Pauli operators by Trotterization, wherein the Pauli gadgets have a same sequencing by set as the Pauli operators;
• diagonalising each set of Pauli gadgets to convert the Pauli gadgets into phase gadgets;
• and
• transforming the phase gadgets into one- and two-qubit native gates to generate the quantum circuit;
• wherein the UCC Ansatz corresponds to a molecular structure.

A system for generating a quantum circuit from a Unitary Coupled Cluster (UCC) Ansatz, wherein the Ansatz represents an excitation of a reference state by a parameterised operator including excitation operators, wherein the Ansatz includes multi-qubit Pauli operators that are determined from each excitation operator, and wherein the system comprises:

• a partitioning arrangement that is configured to partition the Pauli operators into mutually commuting sets and sequencing the Pauli operators by set;
• a generating arrangement that is configured to generate Pauli gadgets from the Pauli operators by Trotterization, wherein the Pauli gadgets have a same sequencing by set as the Pauli operators;
• a diagonalizing arrangement that is configured to diagonalise each set of Pauli gadgets to convert the Pauli gadgets into phase gadgets;
• and
• a transforming arrangement that is configured to transform the phase gadgets into one- and two-qubit native gates to generate the quantum circuit;
• wherein the UCC Ansatz corresponds to a molecular structure.

A system for generating a quantum circuit from a Hamiltonian using a parameterised operator including excitation operators to represent an excitation of a reference state, wherein the system is configured to determine multi-qubit Pauli operators from each excitation operator, wherein the system comprises:

• a partitioning arrangement that is configured to partition the Pauli operators into mutually commuting sets and sequencing the Pauli operators by set;
• a generating arrangement that is configured to generate Pauli gadgets from the Pauli operators by Trotterization, wherein the Pauli gadgets have the same sequencing by set as the Pauli operators;
• a diagonalizing arrangement that is configured to diagonalise each set of Pauli gadgets to convert the Pauli gadgets into phase gadgets;
• and
• a transforming arrangement that is configured to transform the phase gadgets into one- and two-qubit native gates to generate the quantum circuit;
• wherein the Hamiltonian corresponds to a molecular structure.