“…In fact, on a quantum device the natural way is to solve the chemical system in second quantization [3,4,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33] formulated in terms of fermionic annihilation and creation operators. Because of the different statistics there is no direct one-to-one mapping: each fermion operator must be represented by a string of qubit operators, which induces long-range qubit-qubit correlations in the system and places demanding requirements on the connectivity and the number of gates (see Section 4.1).…”