Quantum Field Theory and Tracking of Indistinguishable Targets

In many particle physics, the Fock space approach is used to study systems with unknown and variable particle numbers. Originally introduced for quantum systems, it can be applied to classical statistical systems, too. In this paper we review the main properties of the Fock space approach, including the second quantization formulation, and demonstrate the correspondence to approaches in multi-target tracking dealing with varying numbers of indistinguishable targets. The correspondence include the representation of the multi-object state, the symmetrized probability density for indistinguishable objects, set integrals, the expectation values of linear operators, and the probability generating functional. The challenges of many particle physics and multi-target tracking are contrasted and possible applications of field theoretic techniques to multi-target tracking are discussed.