Quantum Synchronization in Nitrogen-Vacancy Centers in Diamonds

Classical synchronisation is the adjustment of the rhythm of an oscillator to either weak external driving or weak coupling with another oscillator. Motivated by its universality and repleteness in the classical world, synchronisation in the quantum regime has been recently studied and several applications have been proposed. We present the first study of one such application. We study synchronisation as a thermal machine in NV centres in diamonds, where we observe this phenomenon in the spin-1 ³A₂ symmetric electronic ground states (m_s = 0, ±1). We create an undriven system by introducing incoherent couplings between |0> and |+1> and between |+1> and |−1>. We introduce decoherence by inducing a Gaussian noise which effectively reduces the T₂^*. A coherent drive between |0> and |−1> is implemented with a small variable detuning, and we observe the quantum analogue of an Arnold-tongue. Coherent and incoherent contributions to the output power are discussed and related to synchronisation dynamics.