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The Key player problem in electric power grids

The Key player problem in electric power grids

Identifying key players is a fundamental problem in network theory. Its origin can be traced back to social sciences and the problem led to ranking algorithms from most to least important player based on the structure of the considered network. Perhaps the most famous such ranking is google’s PageRank. Identifying which power plant or which…

New Rigaku XtaLAB Synergy-S diffractometer installed in the Laboratory of Crystallography

New Rigaku XtaLAB Synergy-S diffractometer installed in the Laboratory of Crystallography

A new single-crystal X-ray diffractometer was installed in the Laboratory of Crystallography. This dual micro-focus source diffractometer (Mo, Cu) is equipped with a new generation curved photon counting X-ray detector (RIGAKU Hypix arc 150), allowing very fast measurements since more data are collected in a single exposure. The detector has almost zero noise, fast readout…

RTS1 CQFD “Le noir plus noir que noir”, interview of Prof. Alberto Morpurgo

RTS1 CQFD “Le noir plus noir que noir”, interview of Prof. Alberto Morpurgo

There was the black colour. There is now an even more black coulour. An ultra-black that is of particular interest to artists who can now rely on scientists to get ever closer to the black. Stéphane Délétroz interviews Alberto Morpurgo, professor at DQMP and expert in nanoelectronics. Listen to the radio broadcast Find also the…

Scanning near-field optical microscopy of LaAlO3/SrTiO3 heterostructures

Scanning near-field optical microscopy of LaAlO3/SrTiO3 heterostructures

The interface between LaAlO3 and SrTiO3 hosts a conducting two dimensional electron system with many interesting properties. Since its discovery in 2004, this system has been intensively studied but there are still several open questions mainly related to the presence of local modulations of the electronic properties. Visualizing these effects remains challenging as it requires…

On-demand control of terahertz and infrared waves

On-demand control of terahertz and infrared waves

Researchers from the University of Geneva and the University of Manchester have confirmed experimentally the theory of very strong magneto-optical resonance in graphene. The ability to control infrared and terahertz waves using magnetic or electric fields is one of the great challenges in physics that could revolutionise opto-electronics, telecommunications and medical diagnostics. A theory from…

A family of finite-temperature electronic phase transitions in graphene multilayers

A family of finite-temperature electronic phase transitions in graphene multilayers

The discovery of graphene –a single crystalline sheet of carbon atoms– represents a true breakthrough because not only showcases the amazing level of material control that has been reached, but also it has enabled the observation of a plethora of fascinating physical phenomena. It has been appreciated since the very first days that graphene layers…

Quantum Magnets under Pressure

Quantum Magnets under Pressure

Quantum magnets have evolved over the past decade into systems of large interest in fundamental and, increasingly, in applied physics. Their exceptional properties, including non-magnetic ground states, fractionalised excitations and topological order, have become candidate resources for quantum information and computing. Application in spintronic devices are possible if spin interactions can be controlled. It has long been known that…

Ultracold atoms used to verify 1963 prediction about 1D electrons

Ultracold atoms used to verify 1963 prediction about 1D electrons

Physicists from Rice University and the University of Geneva have verified a key prediction from a 55-year-old theory about one-dimensional electronics that is increasingly relevant thanks to Silicon Valley’s inexorable quest for miniaturization. “Chipmakers have been shrinking feature sizes on microchips for decades, and device physicists are now exploring the use of nanowires and nanotubes…

The apparent inner calm of quantum materials

The apparent inner calm of quantum materials

Transitions between different phases of matter are part of our day-to-day lives: when water freezes, for example, it passes from liquid to solid state. Some of these transitions may be of a different kind, resulting from so-called topological excitations that force all the particles to act in unison. Researchers from the University of Geneva (UNIGE)…

When superconductivity disappears in the core of a quantum tube

When superconductivity disappears in the core of a quantum tube

Predicting the behaviour of electrons in a material is not easily done. Physicists from the University of Geneva (UNIGE), ETH Zurich and EPFL replaced the electrons with ultra-cold neutral lithium atoms that they had circulated in a one-dimensional quantum tube. The scientists were then able to confirm an unusual state of matter that retains its…

Réalisation : Sur Mesure concept