Classical Preprocessing for Efficient State Preparation in Quantum Computers

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

• compute, using a classical computer, a modified quantum state, the modified quantum state is computed based on an application of a transformation on an initial quantum state, the initial quantum state is associated with one or more qubits, a quantum circuit comprising the one or more qubits and an original sub-circuit that is configured to set the initial quantum state on the one or more qubits;
• and
• generate a modified quantum circuit based on the quantum circuit, the modified quantum circuit is configured to be executed by a quantum computer, the modified quantum circuit comprising the one or more qubits,
• wherein the modified quantum circuit excludes the original sub-circuit,
• wherein the modified quantum circuit comprises a modified sub-circuit, the modified sub-circuit is configured to set the modified quantum state on the one or more qubits of the modified quantum circuit during one or more cycles of the modified quantum circuit, wherein the modified sub-circuit is configured to apply an inverse transformation on the modified quantum state of the one or more qubits at one or more subsequent cycles of the modified quantum circuit, the one or more subsequent cycles of the modified quantum circuit are subsequent to the one or more cycles, the inverse transformation is configured to inverse the transformation, whereby an application of the inverse transformation in the modified quantum circuit is configured to restore the initial quantum state or an approximation thereof.

A computer program product comprising a non-transitory computer readable medium retaining program instructions, which program instructions when read by a processor, cause the processor to:

• compute, using a classical computer, a modified quantum state, the modified quantum state is computed based on an application of a transformation on an initial quantum state, the initial quantum state is associated with one or more qubits, a quantum circuit comprising the one or more qubits and an original sub-circuit that is configured to set the initial quantum state on the one or more qubits;
• and
• generate a modified quantum circuit based on the quantum circuit, the modified quantum circuit is configured to be executed by a quantum computer, the modified quantum circuit comprising the one or more qubits,
• wherein the modified quantum circuit excludes the original sub-circuit,
• wherein the modified quantum circuit comprises a modified sub-circuit, the modified sub-circuit is configured to set the modified quantum state on the one or more qubits of the modified quantum circuit during one or more cycles of the modified quantum circuit, wherein the modified sub-circuit is configured to apply an inverse transformation on the modified quantum state of the one or more qubits at one or more subsequent cycles of the modified quantum circuit, the one or more subsequent cycles of the modified quantum circuit are subsequent to the one or more cycles, the inverse transformation is configured to inverse the transformation, whereby an application of the inverse transformation in the modified quantum circuit is configured to restore the initial quantum state or an approximation thereof.