Abstract: I will present our trapped-ion system with engineered competing dissipation channels, implemented independently on two ions of different specied co-trapped in the same potential well. We explore the phase diagram of the system, which is analogous to that of a (phonon) laser by precise control of the spin-oscillator couplings and the dissipative channels. I will present our experimental results including the reconstruction of the phonon distribution which allows us to show the phase transition from a dark to the bright and coherent lasing phase. In contrast to earlier work [1] our laser works close to the quantum ground state with average phonon numbers below ten. In the lasing phase, I show phase locking of the oscillator to an additional resonant drive, which breaks the symmetry of tne Wigner function. I will also show the intrinsic phase diffusion of the lasing process starting from a displaced coherent state. The toolbox of techniques is extensible to squeezed laser systems through the use of additional laser drives, is predicted to offer advantages in sensing [2], and provides methods for the general use of the mixed-ion-species platform in the simulation of dissipative spin-boson systems.
[1] K. Vahala, M. Herrmann, S. Knünz, V. Batteiger, G. Saathoff, T. W. Hänsch, and T. Udem, “A phonon laser,” Nature Physics, vol. 5, no. 9, pp. 682–686, aug 2009.
[2] S. Fernandez-Lorenzo and D. Porras, “Quantum sensing close to a dissipative phase transition: Symmetry breaking and criticality as metrological resources,” Phys. Rev. A, vol. 96, p. 013817, Jul 2017.