Spin correlations in two-particle quantum systems

Guo-Feng Zhang, Heng Fan, Ai-Ling Ji +3 more

Catherine J. Stevenson, Jordan Kyriakidis

We probe for statistical and Coulomb-induced spin textures among the low-lying states of repulsively interacting particles confined to potentials that are both rotationally and time-reversal invariant. In particular, we focus on two-dimensional quantum dots and employ configuration-interaction techniques to directly compute the correlated many-body eigenstates of the system. We produce spatial maps of the single-particle charge and spin density and verify the annular structure of the charge density and the rotational invariance of the spin field. We further compute two-point spin correlations to determine the correlated structure of a single component of the spin vector field. In addition, we compute three-point spin-correlation functions to uncover chiral structures. We present evidence for both chiral and quasitopological spin textures within energetically degenerate subspaces in the three- and four-particle systems.

Leonid V. Il'ichov

The paper considers the role of spin correlation swapping in spatial correlations between recombination events in a mixture of two ground-state Fermi gases. A simple geometrical structure of swapping transformation of the spin correlations was found and used. The results seem to be useful for studies of structure and the evolution of spin correlations under localized events of particle conversions in extended quantum systems.

Jean-Louis Basdevant, Jean Dalibard

C.J.M. Schoutens, Jean-Sébastien Caux, Rob Hagemans

Daniel M. Greenberger, Michael Horne, Abner Shimony +1 more

It is demonstrated that the premisses of the Einstein–Podolsky–Rosen paper are inconsistent when applied to quantum systems consisting of at least three particles. The demonstration reveals that the EPR program contradicts quantum mechanics even for the cases of perfect correlations. By perfect correlations is meant arrangements by which the result of the measurement on one particle can be predicted with certainty given the outcomes of measurements on the other particles of the system. This incompatibility with quantum mechanics is stronger than the one previously revealed for two-particle systems by Bell’s inequality, where no contradiction arises at the level of perfect correlations. Both spin-correlation and multiparticle interferometry examples are given of suitable three- and four-particle arrangements, both at the gedanken and at the real experiment level.