Quantum Coherence from a Few Incoherent Bosons

An engineered hybrid interaction of a few incoherent bosons with a cooled discrete-level system may give rise to substantial quantum coherence, an essential resource with diverse applications for quantum technology. This is in contrast to the expected requirement of intense and coherent external drives in current technologies. Substituting such external drives with internal hybrid processes stimulated by mere thermal energy may then contribute to reduced energy consumption in observing and using quantum phenomena. This low-energy emergence of quantum coherence is then suitable for proof-of-principle exploration with recent experiments in platforms such as trapped ions and superconducting circuits. The emergence of quantum coherence in a single qubit from incoherent states, important for quantum technology, is a challenging task. Unitary qubit-oscillator dynamics is sufficient for large qubit coherence to emerge from incoherent states, over a wide variety of qubit-oscillator interactions even without deep strong coupling. Thermally driven nonlinear unitary dynamics, even including the free evolution, may substitute for strongly driven linearized dynamics for such tasks.image