Setting a target quantum state on a qubit using an ansatz parametric circuit

A method comprising:

• obtaining a target quantum state;
• obtaining a representation of an original quantum circuit, wherein the original quantum circuit comprises a qubit with an unknown quantum state;
• generating a parametric quantum circuit, said generating the parametric quantum circuit comprises:
• setting the unknown quantum state on at least one qubit at an initial cycle of the parametric quantum circuit,
• generating an ansatz parametric circuit to receive the unknown quantum state from the at least one qubit, and to output a processed quantum state,
• generating a detection sub-circuit to indicate a distance measure of the processed quantum state from the target quantum state,
• executing the parametric quantum circuit a plurality of times on a quantum computer,
• based on said executing the parametric quantum circuit, iteratively adjusting parameter values of the ansatz parametric circuit until obtaining a parameter value that, when executed by the quantum computer, causes the parametric quantum circuit to output an approximation of a zero as the distance measure of the processed quantum state from the target quantum state, wherein said iteratively adjusting the parameter values of the ansatz parametric circuit is part of a Variational Quantum Algorithm (VQA) scheme, and wherein the approximation of a zero is within a threshold deviation from zero, and
• upon determining that the distance measure of the processed quantum state from the target quantum state corresponds to the approximation of a zero, returning output data corresponding to the ansatz parametric circuit;
• and
• adjusting the representation of the original quantum circuit based on the output data.

An apparatus comprising a processor and a coupled memory, the processor being adapted to perform:

• obtaining a target quantum state;
• obtaining a representation of an original quantum circuit, wherein the original quantum circuit comprises a qubit with an unknown quantum state;
• generating a parametric quantum circuit, said generating the parametric quantum circuit comprises:
• setting the unknown quantum state on at least one qubit at an initial cycle of the parametric quantum circuit,
• generating an ansatz parametric circuit to receive the unknown quantum state from the at least one qubit, and to output a processed quantum state,
• generating a detection sub-circuit to indicate a distance measure of the processed quantum state from the target quantum state,
• executing the parametric quantum circuit a plurality of times on a quantum computer,
• based on said executing the parametric quantum circuit, iteratively adjusting parameter values of the ansatz parametric circuit until obtaining a parameter value that, when executed by the quantum computer, causes the parametric quantum circuit to output an approximation of a zero as the distance measure of the processed quantum state from the target quantum state, wherein said iteratively adjusting the parameter values of the ansatz parametric circuit is part of a Variational Quantum Algorithm (VQA) scheme, and wherein the approximation of a zero is within a threshold deviation from zero, and
• upon determining that the distance measure of the processed quantum state from the target quantum state corresponds to the approximation of a zero, returning output data corresponding to the ansatz parametric circuit;
• and
• adjusting the representation of the original quantum circuit based on the output data.