where Tp = â † a âi -â † i âa with i ∈ occ, a ∈ vir, or Tp = â † a â † b âi âj -â † j â † i âb âa with i > j ∈ occ, a > b ∈ vir. However, when the operators are mapped into quantum gates, additive form of operators on the exponents of UCCSD is not implementable on real NISQ devices.