How to build a quantum Newton’s cradle

A quantum analogue of the popular “Newton’s cradle” toy has been proposed by a duo of physicists in Italy. Like momentum transferred in the toy, the team argues that it should be possible to achieve the nearly perfect transmission of … Read the rest

Newton cradle

Newton’s cradle (Fig. 1) is a valuable paradigm of how physical mechanisms are concealed into nature. It is a device based on classical mechanics that demonstrates the conservation of momentum and energy. On the other hand, Quantum Mechanics has been … Read the rest

Anomalous Heat Transport in Low Dimensions

Many phenomena in nature occur under nonequilibrium stationary conditions. For instance, an electric current is obtained by applying an electric field along a conductor or heat is transported when a temperature gradient is established between two boundaries of a material.

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Ionic liquids: a spectroscopic investigation

Ionic liquids (IL) are salts formed by organic cations, like imidazolium, pyrrolidinium, ammonium or alkyl phosphonium, and organic/inorganic anions, like hexafluorophosphate, tetrafluoroborate, triflate, dicyanamide, tetracyanamethanide or bis(trifluoromethanesulfonyl)imide (TFSI). The presence of such bulky and asymmetric ions decreases the ion-ion interactions … Read the rest

Solid state hydrogen storage

Hydrogen is attracting renewed interest as an energy carrier, due to the necessity of finding ecological energy media which may decrease the environmental pollution from fossil fuels. Hydrogen storage represents a nodal point for the development of a hydrogen economy.… Read the rest

Volume collapse transition in Ce

Crystalline Ce has a remarkable phase diagram in that is the solid state analogue of a Van der Walls system with a line of discontinuous transitions ending at a critical point.

The two phases alpha and gamma have the same … Read the rest

Polarons in strongly correlated systems

In system with strong electron-phonon interaction, the carriers loose mobility, ultimately acquiring polaronic character. A polaron is a state in which the phonon and electron degrees of freedom are strongly entangled, and the presence of an electron is associated to … Read the rest

Graphene and carbon-based new materials

The investigation of the electronic properties of graphene (single hexagonal layer of carbon atoms) has attracted a renewed interest after the development of recent techniques which permit to produce and manage single-layer (and also multilayer) samples of this materials. Nowadays … Read the rest

Competing orders in Iron based superconductors

In January 2008 a new family of superconductors has been discovered with FeAs layers. Iron is a magnetic ion and in traditional superconductors small amounts of magnetic impurities kill superconductivity so an iron based superconductor is at first sight surprising.… Read the rest

Frustrated Phase Separation

A large variety of systems with competing short and long range interactions self-organizes in domain patterns as reviewed by Seul and Andelman. Examples range from magnetic systems (left figure A) to organic systems (left figure B).

Fig. 1: Frustrated phase

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Polarons in organic single crystal FET’s

Organic field effect transistors (OFETs) are providing exciting prospects for potential applications in electronics. The active elements of these devices use “plastic” semiconductors, based on carbon and hydrogen. Among the advantages compared to classical silicon transistors, this new generation of … Read the rest

Unconventional antiferromagnetism due to Dzyaloshinskii-Moriya interactions

The relevance of antisymmetric superexchange interactions in spin Hamiltonians describing quantum antiferromagnetic (AF) systems has been acknowledged long ago by Dzyaloshinskii. Soon after, Moriya showed that such interactions arise naturally in perturbation theory due to the spin-orbit coupling in magnetic … Read the rest

Strongly Correlated Superconductivity: how can repulsion enhance Tc?

In conventional superconductors, the repulsive interaction between electrons opposes to phonon-mediated pairing. We have shown that even phonon-mediated superconductivity can be favoured by repulsion under suitable conditions which are realized in fullerenes.

Trivalent alkali-doped fullerenes are almost certainly electron-phonon superconductors, … Read the rest

Spin-orbit interaction and spintronics

One of the new frontiers in condensed matter physics is development and engineering of electronic devices which carrier “bit” informations in the spin degree of freedom of the electronc instead of their charge. This research line is called indeed “spintronics”. … Read the rest

Inhomogeneities in Cuprates

If the mechanism of high-Tc superconductivity is electronic, to understand the electronic excitation spectrum is as important as to understand phonons was important to develop BCS theory. In this regard charge and spin inhomogeneous states, often found in … Read the rest

Unconventional electron-phonon interaction and nonadiabatic effects

The conventional understanding of the electron-phonon phenomenology in condensed matter strongly relies on the adiabatic assumption, i.e. that nuclei dynamics is much slower than the electron one. In solid crystals the validity of this assumption is usually related to the … Read the rest