F. Henkel, M. Krug, J. Hofmann, W. Rosenfeld, M. Weber, and H. Weinfurter
Phys. Rev. Lett. 105, 253001 (2010)
http://link.aps.org/doi/10.1103/PhysRevLett.105.253001
We experimentally demonstrate a detection scheme suitable for state analysis of single optically trapped atoms in less than 1 μs with an overall detection efficiency η exceeding 98%. The method is based on hyperfine-state-selective photoionization and subsequent registration of the correlated photoion-electron pairs by coincidence counting via two opposing channel electron multipliers.
EPL, 97 (2012) 20012
We introduce a quantum version of the Game of Life and we use it to study the emergence of complexity in a quantum world. We show that the quantum evolution displays signatures of complex behaviour similar to the classical one, however a regime exists, where the quantum Game of Life creates more complexity, in terms of diversity, with respect to the corresponding classical reversible one.
Phys. Rev. A 84, 012312 (2011)
The number of defects which are generated upon crossing a quantum phase transition can be minimized by choosing properly designed time-dependent pulses. In this work we determine what are the ultimate limits of this optimization. We discuss under which conditions the production of defects across the phase transition is vanishing small.
The first QUIE2T review will take place on Tuesday, 3rd of May 2011 in Bratislava.
Details will follow but we will try to schedule the review meeting such that we can travel on the evening of the same day to Budapest, as FET 11 will start on the next day 9am with the keynote speech
J. I. Cirac, P. Maraner, and J.K. Pachos
Phys. Rev. Lett. 105, 190403 (2010) http://link.aps.org/doi/10.1103/PhysRevLett.105.190403
We demonstrate that Dirac fermions self-interacting or coupled to dynamic scalar fields can emerge in the low energy sector of designed bosonic and fermionic cold atom systems. We illustrate this with two examples defined in two spacetime dimensions. The first one is the self-interacting Thirring model. The second one is a model of Dirac fermions coupled to a dynamic scalar field that gives rise to the Gross-Neveu model.
L. Mazza, M. Rizzi, M. Lewenstein, and J. I. Cirac
Phys. Rev. A 82, 043629 (2010) http://link.aps.org/doi/10.1103/PhysRevA.82.043629
We study two many-body systems of bosons interacting via an infinite three-body contact repulsion in a lattice: a pairs quasicondensate induced by correlated hopping and the discrete version of the Pfaffian wave function. We propose to experimentally realize systems characterized by such interaction by means of a proper spin-1 lattice Hamiltonian: spin degrees of freedom are locally mapped into occupation numbers of emerging bosons, in a fashion similar to spin-1/2 and hardcore bosons. Such a system can be realized with ultracold spin-1 atoms in a Mott insulator with a filling factor of 1.
P. Hauke, T. Roscilde, V. Murg, J.I. Cirac, R. Schmied
New J. Phys. 12, 053036, (2010) http://dx.doi.org/10.1088/1367-2630/12/5/053036
We investigate a system of frustrated hardcore bosons, modeled by an XY antiferromagnet on the spatially anisotropic triangular lattice, using Takahashi's modified spin-wave (MSW) theory. In particular, we implement ordering vector optimization on the ordered reference state of MSW theory, which leads to significant improvement of the theory and accounts for quantum corrections to the classically ordered state. The MSW results at zero temperature compare favorably to exact diagonalization (ED) and projected entangled-pair state (PEPS) calculations.
QUIE2T was represented by Carmen Zeques at the FET Coordination Action Workshop, 26-27 October 2010 in Brussels.
The presentation can be downloaded from the workshop web site.
Phys. Rev. Lett. 107, 130404 (2011)
We investigate the optimal control of open quantum systems, in particular, the mutual influence of driving and dissipation. A stochastic approach to open-system control is developed, using a generalized version of Krotov’s iterative algorithm, with no need for Markovian or rotating-wave approximations. The application to a harmonic degree of freedom reveals cooperative effects of driving and dissipation that a standard Markovian treatment cannot capture.
QUIE2T was present at the ICT 2010 conference in Brussels.
As part of the WP3 activities QUIE2T presented an exhibit at the ICT 2010 conference in Brussels, 27 – 29 September 2010. The event was very well-attended both by specialists and non-specialists including well-known media people.