All-optical dissipative discrete time crystals

Abstract

Time crystals are periodic states exhibiting spontaneous symmetry breaking in either time-independent or periodically-driven quantum many-body systems. Spontaneous modification of discrete time-translation symmetry in periodically-forced physical systems can create a discrete time crystal (DTC) constituting a state of matter possessing properties like temporal rigid long-range order and coherence, which are inherently desirable for quantum computing and information processing. Despite their appeal, experimental demonstrations of DTCs are scarce and significant aspects of their behavior remain unexplored. Here, we report the experimental observation and theoretical investigation of DTCs in a Kerr-nonlinear optical microcavity. Empowered by the self-injection locking of two independent lasers with arbitrarily large frequency separation simultaneously to two same-family cavity modes and a dissipative Kerr soliton, this versatile platform enables realizing long-awaited phenomena such as defect-carrying DTCs and phase transitions. Combined with monolithic microfabrication, this room-temperature system paves the way for chip-scale time crystals supporting real-world applications outside sophisticated laboratories.

Soliton microcombs in whispering gallery mode crystalline resonators with broadband intermode interactions

“…Moreover, on the study of soliton physics, they represent an ideal platform which is almost free from high-order dispersive or nonlinear effects. A number of dissipative soliton dynamics have been demonstrated with high-level of agreement with the theory, such as the soliton double resonance [34], soliton pulse scaling [35], soliton breathers [36], soliton molecules [37], soliton crystals [38] and soliton behaviors to intermode interactions [39]. Indeed, effects of intermode interactions have been widely observed and studied in soliton microcombs, which in most cases are reflected as localized power enhancement on certain comb modes [40].…”

Observation of a continuous time crystal

“…The system develops a subharmonic response, i.e., an intrinsic oscillation at a frequency slower than that of the drive. Initially, it was argued that dissipation, and hence the use of open systems, must be carefully avoided, until so called dissipative discrete time crystals were theoretically predicted [18,19] and experimentally realized [20]. As shown in a number of theoretical works [21][22][23], the use of open systems comes with the surprising consequence that continuous instead of periodic driving suffices to induce time crystal dynamics.…”

A Decade of Time Crystals: Quo Vadis?

“…However, it is known from the systematic studies of Prigogine and others that open systems that are out of thermodynamic equilibrium can possess steady states that spontaneously break the time translation symmetry and reveal periodic evolution in time [27,28]. In the context of time crystals, dissipative time-independent and periodically driven systems have recently been investigated theoretically and experimentally [29][30][31][32][33][34]. They are important from the point of view of practical applications because in the real world, i.e., outside advanced laboratories, it can be difficult to avoid contact with the environment.…”

“…Treating the environment as an ally is thus another strategy to realize time crystals, which can be used in future practical applications. Two experiments demonstrating dissipative discrete time crystals have been performed recently, in ultra-cold atoms [33] and in an optical system [34]. In the latter case, one can realize big discrete time crystals that can live forever, i.e., as long as the optical resonator is pumped by laser beams.…”

“…At least in the case of discrete time crystals, the precision of their periodic evolution is limited by the precision of the external periodic drive. However, the fact that they evolve with subharmonic frequencies can be used as a frequency division, which in the optical frequency regime, like in the experiment [34], is highly non-trivial. In order to think about practical applications of time crystals, they must be easy to implement and well controlled experimentally.…”