Critical Theory of Two-Dimensional Mott Transition: Integrability and Hilbert Space Mapping

We reconsider the Mott transition in the context of a two-dimensional fermion model with density-density coupling. We exhibit a Hilbert space mapping between the original model and the Double Lattice Chern-Simons theory at the critical point by use of the representation theory of the q-oscillator and Weyl algebras. The transition is further characterized by the ground state modification. The explicit mapping provides a new tool to further probe and test the detailed physical properties of the fermionic lattice model considered here and to enhance our understanding of the Mott transition(s)

Are Museums Allowed to Keep a Secret? Secret and Sacred Objects at the Weltmuseum Wien.

Today many ethnographic museums are questioning the hierarchical power relationships implicit in the act of representing the cultures of others. In this article I analyze the way that the curator of the South American section of the Weltmuseum Wien chose to deal with the exhibition of sacred and secret objects, that is, those things that only specific categories of individuals are allowed to view. If we exclude storage as a possible solution, what is the proper way to treat artifacts such as these? How should the expectations of an audience attracted to the idea of the exotic, and perhaps forbidden, be satisfied? How can this challenge be transformed into an opportunity to reflect about what we have, or have not, the right to do

Hoarding Symptoms Are Not Exclusive to Hoarders

Hoarding Disorder (HD) was originally conceptualized as a subcategory of Obsessive Compulsive Disorder (OCD), and numerous studies have in fact focused exclusively on investigating the comorbidity between OCD and HD. Hoarding behavior can nevertheless also be found in other clinical populations and in particular in patients with eating disorders (ED), anxiety disorders (AD), major depression (MD), and psychotic disorders (PD). The current study was carried out with the aim of investigating, using a validated instrument such as the Saving Inventory-Revised (SI-R), the presence of HD symptoms in patients diagnosed with ED, AD, MD and PD. Hoarding symptomatology was also assessed in groups of self-identified hoarders (SIH) and healthy controls. The results revealed that 22.5% of the ED patients exceeded the cut-off for the diagnosis of HD, followed by 7.7% of the patients with MD, 7.4% of the patients with AD, and 5.9% of the patients with PD. The patients with ED had significantly higher SI-R scores than the other groups in the Acquisition and Difficulty Discarding scales while the AD, MD, and PD patients were characterized exclusively by Difficulty Discarding. These data suggest to clinicians that hoarding symptoms should be assessed in other types of patients and especially in those affected by Bulimia and Binge eating

Ambipolar Diffusion with a Polytropic Equation of State

Stars form when dense regions of molecular gas in our galaxy collapse due to their self-gravity. For this to occur, the magnetic field supporting these regions must diffuse out through a process known as ambipolar diffusion. We build on previous work by examining a one-dimensional self-gravitating gas with a polytropic equation of state (P∝ρε), considering cases that range from softer (ϵ\u3c1) to stiffer (ϵ\u3e1) than isothermal. Our results indicate that the diffusion time is not very sensitive to ϵ when stiffer than isothermal but is sensitive to ϵ when softer than isothermal. Additionally, the presence of magnetic and density fluctuations reduces the diffusion times, with the shortest diffusion times obtained for gases with large initial magnetic to gas pressure ratios and fairly soft equations of state. However, the diffusion time starts to increase significantly for ϵ ≲ 0.5, indicating that such soft equations of state are inconsistent with observations

Muscle Dysmorphia and its Associated Psychological Features in Three Groups of Recreational Athletes

AbstractMuscle Dysmorphia (MD) is a psychological disorder characterized by the preoccupation with the idea that one’s body is not lean and muscular. The current study aimed to explore MD behaviours and symptoms in three groups of recreational athletes: bodybuilders (BB; n = 42), strength athletes (SA; n = 61), and fitness practitioners (FP; n = 22). Furthermore, we assessed MD-related psychological features as well as possible psychological predictors of MD among groups. Results highlighted that the BB group reported more beliefs about being smaller and weaker than desired compared to the other groups, whereas individuals in the SA group reported setting higher standards for themselves than the FP group. Lastly, orthorexia nervosa and social anxiety symptoms emerged as predictors of MD symptoms in the BB group. Taken together, our findings suggest that individuals in the BB group are characterized by more MD general symptomatology than those in the other groups; furthermore, only orthorexia nervosa and social anxiety may play a specific role in predicting MD general symptoms in bodybuilders.</jats:p

Revising the Intolerance of Uncertainty Model of Generalized Anxiety Disorder: Evidence from UK and Italian Undergraduate Samples

The Intolerance of Uncertainty Model (IUM) of Generalized Anxiety Disorder (GAD) attributes a key role to Intolerance of Uncertainty (IU), and additional roles to Positive Beliefs about Worry (PBW), Negative Problem Orientation (NPO), and Cognitive Avoidance (CA), in the development and maintenance of worry, the core feature of GAD. Despite the role of the IUM components in worry and GAD has been considerably demonstrated, to date no studies have explicitly assessed whether and how PBW, NPO, and CA might turn IU into worry and somatic anxiety. The current studies sought to re-examine the IUM by assessing the relationships between the model’s components on two different non-clinical samples made up of UK and Italian undergraduate students. One-hundred and seventy UK undergraduates and 488 Italian undergraduates completed measures assessing IU, worry, somatic anxiety, depression, and refined measures of PBW, NPO, and CA. In each sample, two mediation models were conducted in order to test whether PBW, NPO, and CA differentially mediate the path from IU to worry and the path from IU to somatic anxiety. Secondly, it was tested whether IU also moderates the mediations. Main findings showed that, in the UK sample, only NPO mediated the path from IU to worry; as far as concern the path to anxiety, none of the putative mediators was significant. Differently, in the Italian sample PBW and NPO were mediators in the path from IU to worry, whereas only CA played a mediational role in the path from IU to somatic anxiety. Lastly, IU was observed to moderate only the association between NPO and worry, and only in the Italian sample. Some important cross-cultural, conceptual, and methodological issues raised from main results are discussed

Universal power-law exponents in differential tunneling conductance for planar insulators near Mott criticality at low temperatures

We consider the low-temperature differential tunneling conductance $G$ for interfaces between a planar insulating material in the Mott-class and a metal. For values of the the applied potential difference $V$ that are not very small, there is a experimentally observed universal regime in which $G \sim V^m$, where $m$ is a universal exponent. We consider the theoretical prediction of the values of $m$ by using the method of Effective Field Theory ($EFT$), which is appropriate for discussing universal phenomena. We describe the Mott material by the $EFT$ pertaining the long-distance behavior of a spinless Hubbard-like model with nearest neighbors interactions previously considered. At the Mott transition, the $EFT$ is known to be given by a double Abelian Chern-Simons theory. The simplest realization of this theory at the tunneling interface yields a Conformal Field Theory with central charges $(c,\bar c) =(1,1)$ and Jain filling fraction $\nu = 2/3$ describing a pair of independent counter-propagating chiral bosons (one charged and one neutral). Tunneling from the material into the metal is, therefore, described by this $EFT$ at the Mott critical point. The resulting tunneling conductance behaves as $G \sim V^{(1/\nu -1)}$, yielding the prediction $m=1/2$, which compares well (within a $10 \%$ deviation) with the results for this exponent in two experimental studies considered here

Mott transition and integrable lattice models in two dimensions

We describe the two-dimensional Mott transition in a Hubbard-like model with nearest neighbors interactions based on a recent solution to the Zamolodchikov tetrahedron equation, which extends the notion of integrability to two-dimensional lattice systems. At the Mott transition, we find that the system is in a d-density wave or staggered flux phase that can be described by a double Chern Simons effective theory with symmetry \su2 \otimes \su2. The Mott transition is of topological nature, characterized by the emergence of vortices in antiferromagnetic arrays interacting strongly with the electric charges and an electric-magnetic duality. We also consider the effect of small doping on this theory and show that it leads to a quantum gas-liquid coexistence phase, which belongs to the Ising universality class and which is consistent with several experimental observations.Comment: 6 pages, two column forma

Effective Field Theories for Electrons in Crystalline Structures

We present an effective field theory formulation for a class of condensed matter systems with crystalline structures for which some of the discrete symmetries of the underlying crystal survive the long distance limit, up to mesoscopic scales, and argue that this class includes interesting materials, such as $Si$-doped $GaAs$. The surviving symmetries determine a limited set of possible effective interactions, that we analyze in detail for the case of $Si$-doped $GaAs$ materials. These coincide with the ones proposed in the literature to describe the spin relaxation times for the $Si$-doped $Ga As$ materials, obtained here as a consequence of the choice of effective fields and their symmetries. The resulting low-energy effective theory is described in terms of three (six chiral) one-dimensional Luttinger liquid systems and their corresponding intervalley transitions. We also discuss the Mott transition within the context of the effective theory.Comment: 24 pages, 3 figure