Quantum fluids exhibit quantum mechanical effects at the macroscopic level, which contrast strongly with classical fluids. Gaindissipative solidstate excitonpolaritons systems are promising emulation platforms for complex quantum fluid studies at elevated temperatures. Recently, halide perovskite polariton systems have emerged as materials with distinctive advantages over other roomtemperature systems for future studies of topological physics, nonAbelian gauge fields, and spinorbit interactions. However, the demonstration of nonlinear quantum hydrodynamics, such as superfluidity and Čerenkov flow, which is a consequence of the renormalized elementary excitation spectrum, remains elusive in halide perovskites. Here, using homogenous halide perovskites single crystals, we report, in both one and twodimensional cases, the complete set of quantum fluid phase transitions from normal classical fluids to scatterless polariton superfluids and supersonic fluids—all at room temperature, clear consequences of the Landau criterion. Specifically, the supersonic Čerenkov wave pattern was observed at room temperature. The experimental results are also in quantitative agreement with theoretical predictions from the dissipative GrossPitaevskii equation. Our results set the stage for exploring the rich nonequilibrium quantum fluid manybody physics at room temperature and also pave the way for important polaritonic device applications.
Mesoscopic quantum systems exhibit complex manybody quantum phenomena, where interactions between spins and charges give rise to collective modes and topological states. Even simple, noninteracting theories display a rich landscape of energy states—distinct manyparticle configurations connected by spin and energydependent transition rates. The ways in which these energy states interact is difficult to characterize or predict, especially in regimes of frustration where manybody effects create a multiply degenerate landscape. Here, we use network science to characterize the complex interconnection patterns of these energystate transitions. Using an experimentally verified computational model of electronic transport through quantum antidots, we construct networks where nodes represent accessible energy states and edges represent allowed transitions. We find that these networks exhibit Rentian scaling, which is characteristic of efficient transportation systems in computer circuitry, neural circuitry, and human mobility, and can be used to measure the interconnection complexity of a network. We find that the topological complexity of the state transition networks—as measured by Rent’s exponent— correlates with the amount of current flowing through the antidot system. Furthermore, networks corresponding to points of frustration (due, for example, to spinblockade effects) exhibit an enhanced topological complexity relative to nonfrustrated networks. Our results demonstrate that network characterizations more »
 Publication Date:
 NSFPAR ID:
 10303245
 Journal Name:
 New Journal of Physics
 Volume:
 21
 Issue:
 12
 Page Range or eLocationID:
 Article No. 123049
 ISSN:
 13672630
 Publisher:
 IOP Publishing
 Sponsoring Org:
 National Science Foundation
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