QUIE2T Quantum Information Entanglement-Enabled Technologies

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

The symposium will be held on the occasion of the 10th anniversary of National Laboratory for Atomic, Molecular, and Optical Physics. The Laboratory is a national consortium involving among other institutions University of Warsaw, a partner in the Q-ESSENCE project. One of the themes of the symposium will be quantum-enhanced metrology. The meeting will provide a platform to exchange ideas and recent development with other sub-fields of modern metrology.
 

The Laboratory for Atomic, Molecular and Optical Physics in Toruń is a national consortium involving among other institutions University of Warsaw, a partner in the Q-ESSENCE project. One of the themes of the symposium will be quantum-enhanced metrology. The meeting will provide a platform to exchange ideas and recent development with other sub-fields of modern metrology.
For further information please visit the event's website: http://famo.fizyka.umk.pl/qmet/.

For more information about the location visit the conference website at:

http://www.qipc2011.ethz.ch/index.php?page=schedule