Spontaneous synchronization and quantum correlation dynamics of open spin systems

Abstract

We discuss the emergence of spontaneous synchronization for an open spin-pair system interacting only via a common environment. Under suitable conditions, and even in the presence of detuning between the natural precession frequencies of the two spins, they are shown to reach a long-lasting transient behavior where they oscillate in phase. We explore the connection between the emergence of such a behavior and the establishment of robust quantum correlations between the two spins, analyzing differences between dissipative and dephasing effects. In particular, in the regime in which synchronization occurs, quantum correlations are more robust for shorter synchronization times and this is related to a separation between system decay rates.

Quantum synchronization as a local signature of super- and subradiance

“…where [14,18]. On the other hand, the decay rate of the oscillating term in σ z k t is always larger than V r .…”

“…As we deal with a system relaxing towards a thermal state (at zero temperature, i.e., the ground state), the emergence of synchronization is assessed in a transient (preasymptotic) regime [14,18]. We focus on the case of spontaneous synchronization, emerging during the dynamics in the absence of pumping sources at the atoms' locations.…”

“…This emergent phenomenon has been largely studied in classical regimes and multidisciplinary contexts. It has been predicted in the quantum regime, in several platforms including harmonic networks [14], mechanical resonators [15], and atomic and ionic setups [16][17][18][19][20]. Different approaches have been considered to frame quantum synchronization referring to both local and global, e.g., quantum correlation, measures (see [21] and references therein).…”

“…For the purpose of this work, we address the collective quantum phenomenon of super-and subradiance to establish a connection with spontaneous synchronization between the local dynamics of the atoms; we therefore consider spontaneous synchronization as the adjustment to a common rhythm of local observables as in Refs. [18,20].…”

Synchronizing quantum harmonic oscillators through two-level systems

“…two-level systems (TLS). A few uncoupled spins interacting with a common environment [17] as well as ensembles of dipoles [18] have been considered. More recently, collective behavior of many spins has been studied in order to establish a connection between synchronization processes and superradiance or subradiance [19].…”