Creating and sharing knowledge for telecommunications

Talk - Topological Matter and Why You Should be Interested

on 27-05-2015

... The next IST Physics Department's colloquium will take place next Wednesday May 27, at 16h30m.

Title: Topological Matter and Why You Should be Interested
Speaker: Steve Simon, University of Oxford
Room: PA1 Auditorium (IST, Mathematics building, Floor 1)

Abstract: In two dimensional topological phases of matter, processes depend on gross topology rather than detailed geometry. Thinking in 2+1 dimensions, particle world lines can be interpreted as knots or links, and the amplitude for certain processes becomes a topological invariante of that link. While sounding rather exotic, we believe that such phases of matter not only exist, but have actually been observed in quantum Hall experiments, and could provide a uniquely practical route to building a quantum computer. Possibilities have also been proposed for creating similar physics in systems ranging from superfluid helium to strontium ruthenate to semiconductor-superconductor junctions to quantum wires to spin systems to cold atoms. More Information..

Seminar - On Landauer principle for non-equilibrium quantum systems

on 21-04-2015

... Mauro Paternostro, Queen's University Belfast

21/04/2015, 10:00
Room 3.10, Mathematics Building, IST

Joint session with the Physics of Information Seminar.

Using the operational framework of completely positive, trace preserving operations and thermodynamic fluctuation relations, I will derive a lower bound for the heat exchange in a Landauer erasure process on a quantum system. The bound comes from a non-phenomenological derivation of the Landauer principle which holds for generic non-equilibrium dynamics. Furthermore the bound depends on the non-unitality of dynamics, giving it a physical significance that differs from other derivations. I will illustrate the framework to the model of a spin-1/2 system I will further investigate the link between information and thermodynamics embodied by Landauer principle in an open-system dynamics embodied by a collision-based mechanism involving a suitable multipartite system and a multi-particle spin reservoir at finite temperature. I will demonstrate that Landauer principle holds, in such an open configuration, in a form that involves the flow of heat dissipated into the environment and the rate of change of the entropy of the system, Quite remarkably, such a principle for heat and entropy power can be explicitly linked to the rate of creation of correlations among the elements of the multipartite system and, in turn, the non-Markovian nature of their reduced evolution. I will illustrate such principle using two paradigmatic cases.

Quantum Computation and Information Seminar

Support: Phys-Info (IT), SQIG (IT), CFIF and CAMGSD, with support from FCT, FEDER and EU FP7, namely via the Doctoral Programme in the Physics and Mathematics of Information (DP-PMI), and projects PEst-OE/EEI/LA0008/2013, QuSim, CQVibes, Landauer (318287) and PAPETS (323901) More Information..