Dissipation-Induced Collective Eects in Two-Level Systems

Till Vorrath

W. Zwerger

John R. Ellis

In the context of non-critical Liouville strings, we clarify why we expect non-quantummechanical dissipative eects to be O E 2 =MP ,w hereE is a typical energy scale of the probe, and MP is the Planck scale. In Liouville strings, energy is conserved at best only as a statistical average, as distinct from Lindblad systems, where it is strictly conserved at an operator level, and the magnitude of dissipative eects could only be much smaller. We also emphasize the importance of nonlinear terms in the evolution equation for the density matrix, which are important for any analysis of complete positivity.

Filippo Giraldi, Francesco Petruccione

Göktuğ Karpat, İ. Yalçınkaya, Barış Çakmak

We explore the environment-induced synchronization phenomenon in two-level systems in contact with a thermal dissipative environment. We first discuss the conditions under which synchronization emerges between a pair of two-level particles. That is, we analyze the impact of various model parameters on the emergence of (anti-)synchronization such as the environment temperature, the direct interaction between the particles, and the distance between them controlling the collectivity of the dissipation. We then enlarge the system to be composed of three two-level atoms to study the mutual synchronization between different particle pairs. Remarkably, we observe in this case a rich synchronization dynamics which stems from different possible spatial configurations of the atoms. Particularly, in sharp contrast with the two-atom case, we show that when the three atoms are in close proximity, the appearance of antisynchronization can be obstructed across all particle pairs due to frustration.

Katja Kustura, Oriol Romero‐Isart, Carlos Gonzalez-Ballestero

We derive a Born-Markov master equation describing the dissipation induced by a bath of lossy but coherently driven two-level systems (TLSs) coupled to a bosonic system via Jaynes-Cummings interaction. We analytically derive all the master-equation rates. We characterize these rates for the particular case of a single-mode system coupled to identical TLSs. We study the steady state of the system and its exotic properties stemming from the nonthermal stationary state of the driven TLS bath. These properties include dissipative amplification, bath-induced linear instability, and both coherent and dissipative squeezing. The master equation is valid for arbitrarily strong TLS driving and it can be generalized to include multilevel systems or other system-bath interaction terms, among others. Our work provides a tool to study and characterize TLS-induced decoherence, a key limiting factor in quantum technological devices based on, for instance, superconducting circuits, magnonic systems, or quantum acoustics.