Instituição de defesa: CBPF - Centro Brasileiro de Pesquisas Físicas

Resumo: In the present work we investigate an effective description of entanglement in spin chains when we do not have access to all degrees of freedom of the system. More specifically, inspired by an experimental situation, we developed a coarse graining approach that describes the detection of a spin chain taking into account a "blurred" detector that does not have sufficient resolution to resolve single sites in the lattice. We constructed a coarsegraining map that takes the information from neighboring sites as a single site. Such idea allows us to study the entanglement behavior taking into account different ranges of resolution of the spin chain and entanglement detectability. In the second part we derive an equation for entanglementin 2xD systems, when the D-dimensional part under goes a coarse graining channel. Such situation can illustrate the measurement process, whena detector (macroscopic object, D-dimensional system), in which we handle only few effective degrees of freedom, interacts with a quantum system(2-dimensional system). Then we see how the entanglement behaves as the detector increases (D increases). This approach can shed light on thequantum-to-classical transition problem.

Área:

Data da defesa: 05/05/2017

Banca: Fernando da Rocha Vaz Bandeira de Melo; M. S. Sarandi; R. S. Sarthour