The spin-boson model usually considers
a spin coupled to a single bosonic bath.
However, some physical situations require
coupling of the spin to multiple environments. For example, spins interacting
with phonons in three-dimensional magnetic materials. Here, we consider a spin
coupled isotropically to three independent
baths. ...
The spin-boson model usually considers
a spin coupled to a single bosonic bath.
However, some physical situations require
coupling of the spin to multiple environments. For example, spins interacting
with phonons in three-dimensional magnetic materials. Here, we consider a spin
coupled isotropically to three independent
baths. We show that coupling to multiple baths can significantly increase entanglement between the spin and its environment at zero temperature. The effect of this is to reduce the spin’s expectation values in the mean force equilibrium state. In contrast, the classical threebath spin equilibrium state turns out to be
entirely independent of the environmental coupling. These results reveal purely
quantum effects that can arise from multibath couplings, with potential applications
in a wide range of settings, such as magnetic materials
