Quantum fluidic transport of charge density waves at high temperatures

A growing body of evidence reveals that charge density waves (CDWs) often show quantum fluidic behavior in their transport and dynamics [APL 118, 184002 (2021)]. The time-correlated soliton tunneling (ST) model proposes that electron-phonon correlates within the CDW condensate (quantum solitons) act much like electrons tunneling through a Coulomb-blockade tunnel junction. Pair creation of fluidic soliton domain walls is prevented by their electrostatic energy below a Coulomb-blockade threshold field, much smaller than the classical depinning field for sliding. Above threshold, the quantum fluid flows periodically, like dripping water, via a hybrid between Zener-like and coherent Josephson-like tunneling. We summarize the time-correlated ST model and compare model simulations with experiment. The ST model shows excellent agreement with measured CDW coherent voltage oscillations, narrow band noise, and current-voltage characteristics. Remarkably, for NbS3 we find nearly precise agreement between quantum theoretical and experimental I-V curves for temperatures up to 474 K. Finally, we discuss broader implications for physics and potential applications. These include quantum reservoir computing and machine learning, as suggested by rapid natural learning phenomena in CDWs.