The entanglement dynamics of a laser-pumped two-level quantum dot pair is investigated in the steady-state. The closely spaced two-level emitters, embedded in a semiconductor substrate, interact with both the environmental vacuum modes of the electromagnetic field reservoir as well as with the lattice vibrational phonon thermostat. We have found that the entanglement among the pair's components is substantially enhanced due to presence of the phonon subsystem. The reason is phonon induced decay among the symmetrical and antisymmetrical two-qubit collective states and, consequently, the population of the latter one. This also means that through thermal phonon bath engineering one can access the subradiant two-particle cooperative state.

The relationship among the entanglement creation within coherently pumped and closely spaced two-level emitters longitudinally coupled with a single-mode boson field, and the subsequent quantum cooling of the boson mode is investigated. Even though the two-level qubits are resonantly driven, we have demonstrated an efficient cooling mechanism well below limits imposed by the thermal background. Furthermore, the cooling effect is accompanied by entanglement of the qubit pair components when the dipole-dipole frequency shift is close to the frequency of the boson mode.The maximum boson mode cooling efficiency realizes on the expense of the entanglement creation.Importantly, this occurs for rather weak external pumping fields protecting the sample from the deteriorations. Finally, the conditions to effectively optimize these effects are described as well. * Electronic address: macovei@phys.asm.md Entanglement in a few-atom system attracted enormous attention over last few decades [1][2][3][4][5][6][7][8]. Small qubit samples may form buildings blocks for even larger networks with huge potential applications for quantum technologies [9][10][11][12][13][14][15][16][17][18][19]. Generally, a thorough description of the entanglement creation in a two-atom system was given in [20]. From this point of view artificial atomic systems have been widely investigated as well. Particularly, experimental realization of entanglement in two coupled charge qubits was performed in [21]. Entanglement of two quantum dots inside a cavity injected with squeezed vacuum was predicted as well, in [22]. Ultra-strong dipole-dipole interacting two-level superconducting flux qubits are naturally entangled through their corresponding environmental reservoir and maximum coherence can be induced too [23]. Furthermore, a pair of moderately dipole-dipole coupled and laser pumped two-level quantum dots get maximal entangled via their environmental phonon thermostat which facilitates also the creation of a subradiant two-qubit state [24].Recently, based on quantum dots systems, a relevant experimental realization of an interconnection among two qubits located five meters apart from each other, via single photons, was reported in Ref. [25].Often to realize quantum states of matter or light one requires ground-state cooled individual or coupled quantum systems, respectively. In this context, cooling of a quantum circuit via coupling to an independent or Dicke-like interacting multiqubit ensemble was demonstrated in [26]. The cooling of a nanomechanical resonator coupled to two interacting flux qubits via the corresponding subradiant Dicke states was demonstrated as well, in Ref. [27]. A scheme for ground-state cooling of a mechanical resonator coupled to two coupled quantum dots forming an effective Λ-type three-level structure was presented in [28].