Originally developed in the context of condensed-matter physics and based on renormalization group ideas, tensor networks have been revived thanks to quantum information theory and the progress in understanding the role of entanglement in quantum many-body systems . Ikerbasque Research Professor Román Orús, one of the world foremost authorities in the field, has just published […]
Quantum simulators—systems that can be engineered and manipulated at will—are useful platforms for verifying model Hamiltonians and understanding more complex or elusive quantum systems. The ability to trap and control particles with the help of well-controlled electromagnetic fields has led to revolutionary advances in the fields of biology, condensed- matter physics, high-precision spectroscopy, and quantum […]
The concept of mean free path is very simple and straightforward: the average distance travelled between collisions by the molecules in a gas, the electrons in a metallic crystal, the neutrons in a moderator, etc. Assuming a couple of things about, for example, how elastic collisions are, it is not difficult to arrive to formulas […]
Cortical neurons often fire together as a group, rather than independently, and these coactive groups, also known as neuronal ensembles (or chains, assemblies, attractors, clicks, motifs, songs, bumps, etc.), could constitute emergent functional units of the brain, as modular building blocks of memories, thoughts, motor programs, computations, or perceptual or mental states. In order to […]
Condensed matter • Materials • Nanotechnology • Quantum physics
The so-called van der Waals materials consist of two-dimensional layers bound by weak van der Waals forces. After the isolation of graphene, the field of two-dimensional van der Waals materials has experienced an explosive growth and new families of two-dimensional systems and block-layered bulk materials have been created. This growth has been fueled mainly by […]
Condensed matter • Materials • Nanotechnology • Quantum physics
For centuries, metals were employed in optical applications only as mirrors and gratings. New vistas opened up in the late 1970s and early 1980s with the discovery of surface-enhanced Raman scattering (SERS) and the use of surface plasmon (collective electronic oscillations at the surface of metals) resonances for sensing. In a simplified picture and in […]
Elements with 4f or 5f electrons in unfilled electron bands and their componuds , which have ions carrying magnetic moments but do not magnetically order, or only do so at very low temperatures, are generally known as heavy-fermion or heavy electron systems because the scattering of the conduction electrons with the magnetic ions results in […]
Condensed matter • Materials • Physics • Quantum physics • Theoretical physics
We all know what an insulator is, don’t we? An insulator is any substance that is a poor conductor of heat and electricity. Both properties ussually occur as a consequence of a lack of mobile electrons.If we want to dive a little deeper into the nature of insulators we make use of energy band theory […]
For a successful application in spintronics of any material, a key problem is to get a reliable control of the electronic spin within it. An ideal candidate for this purpose would be any material which is non-magnetic in the bulk but has a tunable ferromagnetic surface layer with a large splitting of the spin-up and […]
If a nucleus has a nonzero spin, it behaves as a small magnet. Therefore, in an external magnetic field, the nuclear magnetic moment vector precesses about the field direction but only certain otientations are allowed by quantum rules. Thus, for hydrogen (spin 1/2) there are two possible states in the presence of a field, each […]