Postponing Heat Death in Periodically Driven Systems

Speaking of “nonequilibrium systems” is as specific as speaking of “nonelephant animals.” These systems are a diverse bunch, with a tendency for disorder and unpredictability. However, one particular class of nonequilibrium systems—those that are periodically driven—can exhibit order out of this mess. In recent years, mounting theoretical and experimental evidence has shown that periodic driving may be a key ingredient for engineering exotic quantum-mechanical states of matter, such as time crystals and room-temperature superconductors [1]. But a dark cloud has always loomed over this so-called Floquet engineering: the driving leads to heating and the heating kills the order. Antonio Rubio-Abadal from the Max Planck Institute for Quantum Optics in Germany and his colleagues have now explored a window of opportunity where such unwanted heating can be suppressed [2]. Their work motivates further efforts in Floquet engineering to produce new states of matter, such as topological states with no equivalent in the world of equilibrium physics.