Dear all Please be informed about the following Seminar. With best regards, Sandra Künzel ------------------------------------------------------------------------------------------------------ Date: Friday Aug 12, 2011 Time: 16:00 Place: ETH Science City, HPF G 6 Host: Wolf Wüst Towards Quantum Simulations of the Hubbard model with quantum dot arrays Pierre Barthelemy TU Delft

Abstract:

The study of strongly correlated electrons systems is often difficult due to the complexity of interacting quantum systems. Even for moderate size systems, the complexity is too large to be solvable by numerical calculations with classical computers. Feynman[1], and later Lloyd[2], proposed to solve this problem by building controllable and clean quantum systems simulating the Hamiltonian one wants to solve, and study the physics of this Hamiltonian through experiments on these controlled quantum systems.

Laterally-defined quantum dots display very interesting features for a quantum simulator. They naturally map the Hubbard Hamiltonian, their tunability is excellent, and their use in dilution fridge allows access to low temperature phases of the Hubbard model, where magnetic ordering effects start to appear.

In this talk, I will present two different projects aiming to use laterally defined dots for quantum simulations. I will show that a plaquette of four dots allows studying a rather surprising effect called Nagaoka’s ferromagnetism and I will present ideas to realize large arrays of quantum dots for the study of Mott Insulating systems, and, maybe, the observation of the onset of large scale magnetic ordering in the Hubbard model.

[1] Feynman, Simulating Physics with Computers. International Journal of Theoretical Physics 21: 467, (1982) [2] Lloyd, Universal quantum simulators. Science 273, 5278, (1996)

ETH Zurich Sandra Künzel NCCR QSIT (Accounting) HPF E 17 8093 Zurich www.nccr-qsit.ethz.ch