Types of quantum field thories
By the general discussion at zeta function and at functional determinant zeta functions are closely related to 1-loop vacuum amplitudes and to vacuum energy in quantum field theory in general and in string theory in particular.
Concretely, the Rankin-Selberg-Zagier method implies that the partition function of the superstring asymptotes for small proper time to a constant times a converging oscillatory term (reminiscent of the explicit formulae for L-functions) whose frequencies are proportional to the imaginary values of the zeros of the Riemann zeta function (ACER 11).
In other parts of the literature there is the desire to interpret the Riemann zeta function instead as a partition function of a quantum mechanical system. (Notice that the 1-loop vacuum amplitude mentioned before is instead a Mellin transform of the partition function.) The main example here is maybe the Bost-Connes system.
via string theory:
Sergio Cacciatori, Matteo Cardella, Equidistribution Rates, Closed String Amplitudes, and the Riemann Hypothesis (arXiv:1007.3717)
“the Riemann hypothesis can be rephrased in terms of ultraviolet relations occurring in perturbative closed string theory”
Carlo Angelantonj, Matteo Cardella, Shmuel Elitzur, Eliezer Rabinovici, Vacuum stability, string density of states and the Riemann zeta function,JHEP 1102:024,2011 (arXiv:1012.5091)
Sergio L. Cacciatori, Matteo A. Cardella, Uniformization, Unipotent Flows and the Riemann Hypothesis (arXiv:1102.1201)
Yang-Hui He, Vishnu Jejjala, Djordje Minic, From Veneziano to Riemann: A String Theory Statement of the Riemann Hypothesis (arXiv:1501.01975)
via random matrix theory: