Acoustic Higher-Order Topological Insulators Induced by Orbital-Interactions.

The discovery of higher-order topological insulator metamaterials, in analogy with their condensed-matter counterparts, has enabled various breakthroughs in photonics, mechanics, and acoustics. A common way of inducing higher-order topological wave phenomena is through pseudo-spins, which mimic the electron spins as a symmetry-breaking degree of freedom. Here, this work exploits degenerate orbitals in acoustic resonant cavities to demonstrate versatile, orbital-selective, higher-order topological corner states.

Orbital topological edge states and phase transitions in one-dimensional acoustic resonator chains.

Topological phases of matter have attracted significant attention in recent years, due to the unusual robustness of their response to defects and disorder. Various research efforts have been exploring classical and quantum topological wave phenomena in engineered materials, in which different degrees of freedom (DoFs) - for the most part based on broken crystal symmetries associated with pseudo-spins - induce synthetic gauge fields that support topological phases and unveil distinct forms of wave propagation. However, spin is not the only viable option to induce topological effects.

Topological Metamaterials.

The topological properties of an object, associated with an integer called the topological invariant, are global features that cannot change continuously but only through abrupt variations, hence granting them intrinsic robustness. Engineered metamaterials (MMs) can be tailored to support highly nontrivial topological properties of their band structure, relative to their electronic, electromagnetic, acoustic and mechanical response, representing one of the major breakthroughs in physics over the past decade. Here, we review the foundations and the latest advances of topological photonic and phononic MMs, whose nontrivial wave interactions have become of great interest to a broad range of science disciplines, such as classical and quantum chemistry.

Neurofeedback in patients with frontal brain lesions: A randomized, controlled double-blind trial.

Background: Frontal brain dysfunction is a major challenge in neurorehabilitation. Neurofeedback (NF), as an EEG-based brain training method, is currently applied in a wide spectrum of mental health conditions, including traumatic brain injury.

Objective: This study aimed to explore the capacity of Infra-Low Frequency Neurofeedback (ILF-NF) to promote the recovery of brain function in patients with frontal brain injury.

Topological sound in two dimensions.

Topology is the branch of mathematics studying the properties of an object that are preserved under continuous deformations. Quite remarkably, the powerful theoretical tools of topology have been applied over the past few years to study the electronic band structure of crystals. Topological band theory can explain and predict topological phase transitions in a material, and the unusual robustness of certain band structure shapes, such as Dirac cones, against small perturbations.

Promising effect of multi-family therapy on BMI, eating disorders and perceived family functioning in adolescent anorexia nervosa: an uncontrolled longitudinal study.

This contribution reports on the results of an uncontrolled longitudinal study investigating the effects of a Multi-Family Therapy (MFT) as treatment for adolescent Anorexia Nervosa (AN) and the role played by perceived family functioning in these effects. 150 patients (144 females) and their families took part in an MFT and were assessed at the beginning, middle, end of the therapy, as well as 6 and 12 months after the end of therapy. BMI, eating disorders symptomatology (EDI-II) and perceived family functioning (FAD) all improved over the time of MFT, and these benefits remained at both times of follow-up.

Moiré-Driven Topological Transitions and Extreme Anisotropy in Elastic Metasurfaces.

The twist angle between a pair of stacked 2D materials has been recently shown to control remarkable phenomena, including the emergence of flat-band superconductivity in twisted graphene bilayers, of higher-order topological phases in twisted moiré superlattices, and of topological polaritons in twisted hyperbolic metasurfaces. These discoveries, at the foundations of the emergent field of twistronics, have so far been mostly limited to explorations in atomically thin condensed matter and photonic systems, with limitations on the degree of control over geometry and twist angle, and inherent challenges in the fabrication of carefully engineered stacked multilayers. Here, this work extends twistronics to widely reconfigurable macroscopic elastic metasurfaces consisting of LEGO pillar resonators.

Odd Willis coupling induced by broken time-reversal symmetry.

When sound interacts with geometrically asymmetric structures, it experiences coupling between pressure and particle velocity, known as Willis coupling. While in most instances this phenomenon is perturbative in nature, tailored asymmetries combined with resonances can largely enhance it, enabling exotic acoustic phenomena. In these systems, Willis coupling obeys reciprocity, imposing an even symmetry of the Willis coefficients with respect to time reversal and the impinging wave vector, which translates into stringent constraints on the overall scattering response.

Measuring Dirac Cones in a Subwavelength Metamaterial.

The exciting discovery of bidimensional systems in condensed matter physics has triggered the search of their photonic analogues. In this Letter, we describe a general scheme to reproduce some of the systems ruled by a tight-binding Hamiltonian in a locally resonant metamaterial; by specifically controlling the structure and the composition it is possible to engineer the band structure at will. We numerically and experimentally demonstrate this assertion in the microwave domain by reproducing the band structure of graphene, the most famous example of those 2D systems, and by accurately extracting the Dirac cones.

Crystalline Soda Can Metamaterial exhibiting Graphene-like Dispersion at subwavelength scale.

Graphene, a honeycomb lattice of carbon atoms ruled by tight-binding interaction, exhibits extraordinary electronic properties due to the presence of Dirac cones within its band structure. These intriguing singularities have naturally motivated the discovery of their classical analogues. In this work, we present a general and direct procedure to reproduce the peculiar physics of graphene within a very simple acoustic metamaterial: a double lattice of soda cans resonating at two different frequencies.

Crystalline metamaterials for topological properties at subwavelength scales.

The exciting discovery of topological condensed matter systems has lately triggered a search for their photonic analogues, motivated by the possibility of robust backscattering-immune light transport. However, topological photonic phases have so far only been observed in photonic crystals and waveguide arrays, which are inherently physically wavelength scaled, hindering their application in compact subwavelength systems. In this letter, we tackle this problem by patterning the deep subwavelength resonant elements of metamaterials onto specific lattices, and create crystalline metamaterials that can develop complex nonlocal properties due to multiple scattering, despite their very subwavelength spatial scale that usually implies to disregard their structure.

Two models of multiple family therapy in the treatment of adolescent anorexia nervosa: a systematic review.

Multiple family therapy (MFT) is a therapeutic method that brings together several families affected by the same pathology. Although from an ideological and conceptual point of view, MFT is often linked to family therapy and group therapy, it is difficult to define it with precision, a weakness which may in turn hinder research on therapeutic effectiveness. This is most notable in the field of eating disorders (ED) where, in spite of MFT's great popularity, research evidence remains limited.

The effects of a multiple family therapy on adolescents with eating disorders: an outcome study.

Multiple Family Therapy (MFT) has gained increasing popularity in the treatment of eating disorders and many programs have been developed over the past decade. Still, there is little evidence in the literature on the effectiveness on MFT for treating eating disorders. The present study examines the effects of a particular model of Multiple Family Therapy on eating disorder symptoms, quality of life, and percentage of Expected Body Weight (%EBW) in adolescents with eating disorders (ED).

Explicit vs. implicit body image evaluation in restrictive anorexia nervosa.

In the present study we investigated the evaluation of body shapes in patients with restrictive anorexia nervosa (AN) on both automatic and controlled levels. The first aim of the study was to examine whether an ultra-thin ideal or negative attitudes toward overweight might be the motivation behind pathological restriction. The second aim was to investigate the relationship between body figure evaluations, eating disorder symptoms and mood.