Calendar of Physics Talks Vienna

Entanglement of two individual neutral atoms using the Rydberg blockade
Speaker:Dr. Tatjana Wilk (Institut d'Optique, Institut d'Optique)
Abstract:The Rydberg blockade is of great interest for many quantum information processing schemes with neutral atoms, since it provides a way to deterministically entangle two or more atoms and to drive fast quantum gates [1]. A major advancement into this direction is the observation of Rydberg blockade between two 87^Rb atoms individually trapped in two neighbouring dipole traps [2]. A laser coupling ground state |g> and Rydberg state |r> of a single atom does not excite both atoms at the same time because the level of the doubly excited state |rr> is detuned from resonance due to the strong interaction between the Rydberg atoms. The atoms can only absorb a single excitation and are excited into an entangled state (|gr>+|rg>)/sqrt(2). To achieve entanglement between the atoms in their ground states, the Rydberg state is mapped onto another ground state |g'>. The experimental implementation of this scheme and recent results will be discussed [3]. [1] D. Jaksch et al., Phys. Rev. Lett. 85, 2208 (2000). M.D. Lukin et al., Phys. Rev. Lett. 87, 037901 (2001). [2] E. Urban et al., Nature Phys. 5, 110 (2009). A. Gaëtan et al., Nature Phys. (5, 115 (2009). [3] T. Wilk et. al, arXiv:0908.0454.
Date: Tue, 15.09.2009
Time: 10:30
Duration: 60 min
Location:Ernst-Mach-Hörsaal, Strudlhofgasse 4, 2. Stock. 1090 Wien

Searching for the Rosetta Stone of cosmology: the Stochastic Gravitational-Wave Background
Speaker:Dr. Carlo Nicola Colacino (Dipart.di Fisica (Fakultät für Physik)
Date: Thu, 17.09.2009
Time: 11:00
Duration: 60 min
Location:Seminarraum B, Währinger Straße 17, 1. Stock
Contact:R. Beig

Post-selection technique for quantum channels with applications to quantum cryptography
Speaker:Prof. Dr. Matthias Christandl (Qauntum Information Theory Group LMU München, Deutschland)
Date: Thu, 17.09.2009
Time: 14:00
Duration: 60 min
Location:Ernst-Mach-Hörsaal, Strudlhofgasse 4, 2. Stock, 1090 Wien
Contact:Daniela Charlesworth

A high-speed QKD system for metropolitan networks
Speaker:Dr. Akisha Tomita (Quantum Computation and Information, I ERATO-SORST, JST, Japan)
Abstract:A high-speed QKD system is being developed under Japanese government's contracted research project for practical QKD systems from 2005 to 2010. Our system is designed to work with 1.25-GHz clock and to generate the final key at 1Mbits/s through a 10-dB-loss fiber (128 kbits/s x 8 waves.) I will discuss technologies applied to achieve the high speed operation, such as Planar Lightwave Circuit interferometers, WDM clock delivery, and hard-ware key distillation circuit. If time allows, I will briefly introduce joint QKD network demonstration planed in 2010.
Date: Fri, 18.09.2009
Time: 14:00
Location:Ernst-Mach-Hörsaal, Strudlhofgasse 4, 2. Stock, 1190 Wien
Contact:Daniela Charlesworth