Magnetic quantum diesel engine in Ni2

Magnetic Engine for the Single-Particle Landau Problem

“…This is in agreement with the fact that work can only be carried out through a change in generalized coordinates of the system, which in turn gives rise to a change in the eigenenergies [9,10]. A very important assumption for Equation (10) is very well described in [29], where it is mentioned that: "small changes inĤ, which can be considered as a first-order perturbation, only shifts the energy levels of the systems and does not modify its eigenstates".…”

“…On the other hand, the effects of the degeneracy of energy levels on the efficiency and power of an engine quantum machine have been reported in many works in the past [21,22,[28][29][30]. In this same framework, we highlight the work of Mehta and Ramandeep [31], who worked on a quantum Otto engine in the presence of level degeneracy, finding an enhancement of work and efficiency for two-level particles with a degeneracy in the excited state.…”

“…We will follow the treatment of [29,33,34], where they conceive a sequence of quasi-static process that drives the subsystem along the sequence of equilibrium states. To derivate this law simply (in a microscopic approach), consider a system describe by a density operatorρ and a Hamiltonian with an explicit dependence of some parameter that we will call ξ in a generic form [34].…”

“…On the other hand, when the eigenstates of the system Hamiltonian are used as the basis, and the coupling between the system and the environment is weak, the system can be described by a canonical distribution determined byĤ and the density matrix is diagonal in that representation [29]. Therefore, the ensemble-average energy E = Ĥ is reduced to…”

Deep-subwavelength lithography via graphene plasmons

“…Quantum heat engines are typically based on implementations of quantum Carnot, Otto [15], Brayton [16,17], Diesel [16,18] or Stirling cycles [19,20], with a succession of strokes that alternatively extract work and exchange heat with the hot and cold reservoirs. As a result the generation of work is an intermittent process.…”