The realization of a universal quantum computer that can carry out arbitrary computations remains a long term goal. But the technologies developed so far enable us to perform so called quantum simulations. Here assemblies of directly controllable quantum particles form models for complex systems which are difficult to manipulate. A new, promising technique was now developed in the group of Professor Gerhard Rempe at the Max Planck Institute of Quantum Optics in Garching.


The intrinsic rotation of electrons - the "spin" - remains unused by modern electronics. If use as an information carrier were possible, the processing power of electronic components would suddenly increase to a multiple of the present capacity. In cooperation with colleagues from Dortmund, St. Petersburg and Washington, Bochum physicists have now succeeded in aligning electron spin, bringing it to a controlled "waver" and reading it out. The electron spin can also be realigned as required at any time using optical pulses.

ArXiv identifier: 
Martin Plenio
Filippo Caruso, Alex W. Chin, Animesh Datta, Susana F. Huelga, Martin B. Plenio

Transport of excitations through networked systems plays an important role in many areas of physics, chemistry, and biology. The uncontrollable interaction of the transmission network with a noisy environment is usually assumed to deteriorate its transport capacity, especially so when the system is fundamentally quantum mechanical. Here we identify key mechanisms through which dephasing noise, contrary to expectation, may actually aid transport through a dissipative network.

ArXiv identifier: 
Daniel Burgarth
Daniel Burgarth, Koji Maruyama

Identifying the nature of interactions in a quantum system is essential in understanding any physical phenomena. Acquiring information on the Hamiltonian can be a tough challenge in many-body systems because it generally requires access to all parts of the system. We show that if the coupling topology is known, the Hamiltonian identification is indeed possible indirectly even though only a small gateway to the system is used. Surprisingly, even a degenerate Hamiltonian can be estimated by applying an extra field to the gateway.

ArXiv identifier: 
Alvaro Feito Boirac
J.S. Lundeen, A. Feito, H. Coldenstrodt-Ronge, K.L. Pregnell, Ch. Silberhorn, T.C. Ralph, J. Eisert, M.B. Plenio, I.A. Walmsley

Measurement connects the world of quantum phenomena to the world of classical events. It plays both a passive role, observing quantum systems, and an active one, preparing quantum states and controlling them. Surprisingly - in the light of the central status of measurement in quantum mechanics - there is no general recipe for designing a detector that measures a given observable. Compounding this, the characterization of existing detectors is typically based on partial calibrations or elaborate models. Thus, experimental specification (i.e.

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Scientists in the UK and US have shown how to increase photovoltaic efficiencies by attaching nanocrystal quantum dots to patterned semiconductor layers. The approach exploits the phenomenon of non-radiative energy transfer and could, say the researchers, lead to a new generation of more efficient solar cells.

HP Labs - Post-Doctoral Researcher in Experimental QKD

The Quantum Information Processing (QIP) Group is based in HP Labs Bristol UK, and is part of the Information and Quantum Systems Laboratory (IQSL). The QIP group is seeking applicants for a fixed-term research appointment for two years, to work on the next stages of the implementation of "consumer quantum key distribution", HP's most advanced quantum information technology. The appointee will carry out research and development on short-range, free-space QKD for consumer applications.

Application deadline: 
Thursday, March 19, 2009

Quantum computation was a highly speculative enterprise facing serious technological obstacles until a shy young physicist came along. Dave Bacon tells the story of Alexei Kitaev’s big idea. Read more at PhysicsWorld.