A computer-implemented method for determining a control sequence for performing a series of qubit interactions to simulate a fermionic hamiltonian, a computer program product, a quantum circuit, and a method for determining a characteristic of a system

A computer-implemented method for determining a control sequence for performing a series of qubit interactions on a plurality of qubits on a quantum device to simulate a fermionic Hamiltonian H expressible as a sum of one or more tensor products of Pauli matrices,

• wherein the plurality of qubits on the quantum device is arranged into a two-dimensional square lattice qubit layout, where each qubit is arranged to interact with up to four neighboring qubits, and
• wherein the method comprises:
• receiving input parameters of the fermionic Hamiltonian to be simulated, the parameters comprising at least:
• a number of fermionic lattice sites L,
• a number of fermionic modes M in the fermionic lattice, and
• fermionic operator corresponding to interactions between the fermionic modes M,
• projecting the fermionic lattice to the qubit layout of the quantum device such that every fermionic mode is assigned to a qubit of the quantum device, wherein said qubit is referred to as a physical qubit P, wherein the projection between the fermionic modes and the physical qubits P is one to one, and wherein a plurality of further qubits of the quantum device are referred to as ancilla qubits A, said ancilla qubits A not being assigned with any fermionic mode,
• wherein the physical qubits P and the ancilla qubits A are arranged onto horizontal single lines of the two-dimensional square lattice, each horizontal single line comprising at least one string P′ and at least one ancilla qubit A, wherein each string P′ comprises one or more physical qubits P,
• wherein the arrangement of physical qubits P and ancilla qubits A in each single horizontal line of the qubit layout is the same,
• associating each physical qubit P with at least one edge operator E and one vertex operator V
• mapping each fermionic operator to a qubit operator based on the edge operators E and vertex operators V,
• determining a control sequence of qubit interactions, said control sequence comprising at least the qubit operators determined by the mapping.