Dimensional advantage in network cooling with hybrid oscillator-qudit systems

Abstract

We examine the cooling of networks of oscillators through repeated unitary evolution followed by conditional measurement on a finite-dimensional auxiliary system, coupled via Jaynes-Cummings type interaction. We prove that near-perfect cooling of the oscillator to vacuum is fundamentally impossible when the auxiliary system is a qubit, establishing a no-cooling theorem for a two-level regulator. Moving beyond this limitation, we reveal a twofold dimensional advantage of higher-dimensional auxiliaries - reducing the number of required cycles, and enabling the efficient cooling of oscillators with higher initial energies. We further show that, while extending the network leads to a saturation of this dimensional advantage at moderate auxiliary dimensions, near-perfect cooling remains achievable for linear network configurations but fails for star networks. Moreover, we highlight the adaptability of the proposed protocol by demonstrating efficient cooling of hybrid continuous- and discrete-variable systems that naturally support the generation of non-Gaussian and entangled quantum resources.