We demonstrate how to create artificial external non-Abelian gauge potentials acting on cold atoms in optical lattices. The method employs atoms with k internal states, and laser assisted stateâ€¦ (More)

We analyze the problem of sending, in a single transmission, the information required to specify an orthogonal trihedron or reference frame through a quantum channel made out of N elementary spins.â€¦ (More)

For a system of N spins there are quantum states that can encode a direction in an intrinsic way. Information on this direction can later be decoded by means of a quantum measurement. We present hereâ€¦ (More)

The main objective of the work presented here is to understand the appearance of phase transitions in pure gauge and scalar lattice QED, both in the compact as well as the noncompact formulations.

We present the optimal scheme for estimating a pure qubit state by means of local measurements on N identical copies. We give explicit examples for low N. For large N, we show that the fidelityâ€¦ (More)

We present a high statistics analysis of the pure gauge compact U(1) lattice theory using the the worldâˆ’sheet or Lagrangian loop representation. We have applied a simulation method that dealsâ€¦ (More)

We perform a high statistics analysis of the phase transition for the 3D Gonihedric Ising model with Îº = 0. This corresponds to an enhanced symmetry point in a class of models defined by Savvidy andâ€¦ (More)

We analyse the reconstruction of an unknown pure qubit state. We derive the optimal guess that can be inferred from any set of measurements on N identical copies of the system with the fidelity as aâ€¦ (More)

We present the extension of the Lagrangian loop gauge invariant representation in such a way to include matter fields. The partition function of lattice compact U(1)-Higgs model is expressed as a sumâ€¦ (More)