Quantum states are notoriously fragile, and can be destroyed simply through interactions, measurements, and exposure to their surrounding environments. In a new theoretical study published in Physical Review X, Rohan Mittal and colleagues at the University of Cologne have discovered a new way to protect quantum behavior on large scales within systems driven far from equilibrium. Their results could have promising implications for the design of more robust quantum devices.
When quantum many-body systems are driven out of equilibrium, they undergo decoherence, causing quantum correlations and superpositions to break down. Even when such a system is built from entirely quantum components, the effect can cause its behavior to become indistinguishable from that of a classical system on larger scales, making it unsuitable for technologies such as quantum computing or sensing.
So far, researchers have attempted to solve the decoherence problem by fine-tuning two independent parameters: one to push the system to the boundary between two distinct quantum phases, and another to ensure that quantum coherence is maintained at this boundary. In practice, however, the need to account for two parameters simultaneously has made this approach both fragile and experimentally daunting.
