Absence of correlations in dissipative interacting qubits: A no-go theorem

Abstract

Exact solutions of model problems are elusive but potent tools for understanding many-body interacting systems. We study a system of dissipative qubits with the Heisenberg interaction and obtain, for qubits under a certain condition, an exact steady-state solution to the Lindblad master equation describing its dynamics. The physical content of such a solution is a remarkable no-go theorem, which states that for qubits possessing identical ratios of the damping and gain rates, no correlations can emerge between them in the steady state, provided their interaction is in the Heisenberg XXZ form. Notably, this even holds for the more general Heisenberg XYZ interaction if the damping rate equals the gain rate. Two consequences of this theorem are discussed in the context of quantum synchronization of qubits. The first is a complete blockade of quantum synchronization of qubits under the aforementioned condition, an effect reminiscent of, but having a much broader scope than, that found in dissipated Kerr-anharmonic oscillators. The second, and a more important consequence is the possibility of reducing a complex all-to-all qubit network to a much simpler one-to-all network by engineering the dissipation. Such a reduction is desired because it provides an effective tool to optimize the quantum synchronization of a complex qubit network. Finally, we propose two concrete experimental schemes to implement our model and to test our predictions. The no-go theorem opens a new avenue for exactly toggling the correlations of quantum many-body systems on and off without disrupting their interaction.