QUROPE Quantum Information Processing and Communication in Europe

The next Q-ESSENCE Consortium meeting will take place in Barcelona at the ICFO - The Institute of Photonic Sciences on the 09-10.02.2012. The exact schedule of the meeting can be found on the INTRANET website.

This is the traditional QIPC cluster reviews. The program is as follows:

The EU sponsored research initiative QESSENCE (Quantum Interfaces, Sensors, and Communication based on Entanglement) with a 3-year budget of €4.7 million to explore quantum entanglement, is in its final year. The research outcomes are expected to make significant impact on future disruptive technologies and provide enabling physics for larger scale quantum computers in the longer-term.

Just to name a few, the recent highlights of research within the consortium include:

The quantum relative entropy is frequently used as a distance measure between two quantum states, and inequalities relating it to other distance measures are important mathematical tools in many areas of quantum information theory. We have derived many such inequalities in our previous work (K.M.R. Audenaert and J. Eisert, J. Math. Phys. 46, 102104 (2005)). The present paper is a follow-up on this, and provides sharp upper bounds on the relative entropy in terms of the trace norm distance and of the smallest eigenvalues of both states concerned.

Distillation of entanglement using only Gaussian operations is an important primitive in quantum communication, quantum repeater architectures, and distributed quantum computing. Existing distillation protocols for continuous degrees of freedom are only known to converge to a Gaussian state when measurements yield precisely the vacuum outcome. In sharp contrast, non-Gaussian states can be deterministically converted into Gaussian states while preserving their second moments, albeit by usually reducing their degree of entanglement.

We introduce the idea of actually cooling quantum systems by means of incoherent thermal light, hence giving rise to a counter-intuitive mechanism of "cooling by heating". In this effect, the mere incoherent occupation of a quantum mechanical mode serves as a trigger to enhance the coupling between other modes. This notion of effectively rendering states more coherent by driving with incoherent thermal quantum noise is applied here to the opto-mechanical setting, where this effect occurs most naturally.

physics.aps.org/viewpoint-for/10.1103/PhysRevLett.107.12050

Prof. Dan Browne from the University College London in the newest issue of APS Physics writes about the QEssence's researchers latest discovery (prl.aps.org/abstract/PRL/v107/i12/e120501) that using a quantum computer to simulate another quantum system will work even when the modeled system is not isolated from its environment.

We show that the time evolution of an open quantum system, described by a possibly time dependent Liouvillian, can be simulated by a unitary quantum circuit of a size scaling polynomially in the simulation time and the size of the system. An immediate consequence is that dissipative quantum computing is no more powerful than the unitary circuit model.

ID Quantique, a partner in the Q-ESSENCE consortium, is organizing for the 4th time the “Winter School on Practical Quantum Cryptography” taking place from January 17 to 20, 2012 in the Swiss Alps.

The goal of this Winter School is to introduce, to a general audience of physicists and computer scientists
with little or no background in practical quantum cryptography, this exciting topic in a relaxed and
stimulating atmosphere. Special emphasis will be put on practical quantum cryptography system design. The

Q-ESSENCE will support half of the conference fees for two participants.

For more details please visit: http://www.idquantique.com/training-services/winter-school.html