Möller and Otto Respond

Sheldon R. Smith

Cleverson Cherubim, Thiago R. de Oliveira, Daniel Jonathan

We study a quantum Otto cycle that uses a 2-qubit working substance whose Hamiltonian does not commute with itself at different times during unitary strokes. We investigate how the cycle responds to the loss of quantum adiabaticity when these strokes are operated with a finite duration. We find that qualitative features such as the possibility of counter-rotating cycles operating as heat engines, or a cycle efficiency that can increase with a decrease in the temperature difference between the baths, are resilient even to highly nonadiabatic strokes. However, cycle efficiency rapidly decreases, although it can still remain above the standard Otto value for small degrees of quantum nonadiabaticity.

Ralph Eric Turner

An approximation scheme is presented which leads systematically from the exact Moller (or scattering) operator to the eikonal approximation and then to the sudden approximation. In terms of the Moller (or scattering) operator, the eikonal approximation is local in position space and is parametrised by the average incoming free momentum. Carrying the procedure a step further decouples the internal and translational motions to produce the sudden approximation. Distorted as well as straight-line approximations are considered. To do so distorted scattering conditions are presented which define distorted M Moller, transition and scattering operators. Some properties of these operators are discussed. Relations with the usual Moller, transition and scattering operators are presented. Finally, an eikonal approximation to the Moller super-operator is presented which does not depend explicitly upon the form of the dynamics that is used. Quantally, the eikonal Moller super-operator is equivalent to the eikonal Moller operator and, in the limit of small h, reduces to the classical eikonal Moller super-operator. This classical Moller super-operator gives a particle picture for the eikonal approximation in contrast to the traditional wave picture.

Yu Watanabe

Paweł Caban, Jakub Rembieliński, Marta Włodarczyk +3 more

We present the relativistic spin correlation function (and the corresponding probabilities) for a pair of polarized electrons originating from the Moller scattering. This particular state is easy to prepare experimentally; therefore, the results are discussed in view of a possible measurement. We also discuss the state after the Moller scattering in terms of entanglement and polarization transfer.

Marco Giliberti, Luisa Lovisetti