Universal Amplitude Ratios of The Renormalization Group: Two-Dimensional Tricritical Ising Model

The scaling form of the free-energy near a critical point allows for the definition of various thermodynamical amplitudes and the determination of their dependence on the microscopic non-universal scales. Universal quantities can be obtained by considering special combinations of the amplitudes. Together with the critical exponents they characterize the universality classes and may be useful quantities for their experimental identification. We compute the universal amplitude ratios for the Tricritical Ising Model in two dimensions by using several theoretical methods from Perturbed Conformal Field Theory and Scattering Integrable Quantum Field Theory. The theoretical approaches are further supported and integrated by results coming from a numerical determination of the energy eigenvalues and eigenvectors of the off-critical systems in an infinite cylinder.Comment: 61 pages, Latex file, figures in a separate fil

Exact conserved quantities on the cylinder II: off-critical case

With the aim of exploring a massive model corresponding to the perturbation of the conformal model [hep-th/0211094] the nonlinear integral equation for a quantum system consisting of left and right KdV equations coupled on the cylinder is derived from an integrable lattice field theory. The eigenvalues of the energy and of the transfer matrix (and of all the other local integrals of motion) are expressed in terms of the corresponding solutions of the nonlinear integral equation. The analytic and asymptotic behaviours of the transfer matrix are studied and given.Comment: enlarged version before sending to jurnal, second part of hep-th/021109

Modelling the contribution of metacognitions and expectancies to problematic smartphone use

Abstract Background and aims In the current study we have sought to clarify the contribution of metacognitions concerning smartphone use relative to smartphone use expectancies in the relationship between well-established predisposing psychological factors and problematic smartphone use (PSU). We tested a model where psychological distress, impulsivity, and proneness to boredom predict metacognitions about smartphone use and smartphone use expectancies, which in turn predict PSU. Methods A sample of 535 participants (F = 71.2%; mean age = 27.38 ± 9.05 years) was recruited. Results The model accounted for 64% of the PSU variance and showed good fit indices (χ 2 = 16.01, df = 13, P = 0.24; RMSEA [90%CI] = 0.02 [0–0.05], CFI = 0.99; SRMR = 0.03). We found that: (i) when it comes to psychological distress and boredom proneness, negative metacognitions, and both positive and negative expectancies play a mediating role in the association with PSU, with negative metacognitions showing a dominant role; (ii) there is no overlap between positive expectancies and positive metacognitions, especially when it comes to smartphone use as a means for socializing; (iii) impulsivity did not show a significant effect on PSU Direct effects of the predictors on PSU were not found. Discussion and conclusions The current study found additional support for applying metacognitive theory to the understanding of PSU and highlight the dominant role of negative metacognitions about smartphone in predicting PSU

From finite geometry exact quantities to (elliptic) scattering amplitudes for spin chains: the 1/2-XYZ

Initially, we derive a nonlinear integral equation for the vacuum counting function of the spin 1/2-XYZ chain in the {\it disordered regime}, thus paralleling similar results by Kl\"umper \cite{KLU}, achieved through a different technique in the {\it antiferroelectric regime}. In terms of the counting function we obtain the usual physical quantities, like the energy and the transfer matrix (eigenvalues). Then, we introduce a double scaling limit which appears to describe the sine-Gordon theory on cylindrical geometry, so generalising famous results in the plane by Luther \cite{LUT} and Johnson et al. \cite{JKM}. Furthermore, after extending the nonlinear integral equation to excitations, we derive scattering amplitudes involving solitons/antisolitons first, and bound states later. The latter case comes out as manifestly related to the Deformed Virasoro Algebra of Shiraishi et al. \cite{SKAO}. Although this nonlinear integral equations framework was contrived to deal with finite geometries, we prove it to be effective for discovering or rediscovering S-matrices. As a particular example, we prove that this unique model furnishes explicitly two S-matrices, proposed respectively by Zamolodchikov \cite{ZAMe} and Lukyanov-Mussardo-Penati \cite{LUK, MP} as plausible scattering description of unknown integrable field theories.Comment: Article, 41 pages, Late

TBA-like equations and Casimir effect in (non-)perturbative AdS/CFT

We consider high spin, $s$, long twist, $L$, planar operators (asymptotic Bethe Ansatz) of strong ${\cal N}=4$ SYM. Precisely, we compute the minimal anomalous dimensions for large 't Hooft coupling $\lambda$ to the lowest order of the (string) scaling variable $\ell \sim L/ (\ln \mathcal{S} \sqrt{\lambda})$ with GKP string size $\sim\ln \mathcal{S}\equiv 2 \ln (s/\sqrt{\lambda})$. At the leading order $(\ln \mathcal{S}) \cdot \ell ^2$, we can confirm the O(6) non-linear sigma model description for this bulk term, without boundary term $(\ln \mathcal{S})^0$. Going further, we derive, extending the O(6) regime, the exact effect of the size finiteness. In particular, we compute, at all loops, the first Casimir correction $\ell ^0/\ln \mathcal{S}$ (in terms of the infinite size O(6) NLSM), which reveals only one massless mode (out of five), as predictable once the O(6) description has been extended. Consequently, upon comparing with string theory expansion, at one loop our findings agree for large twist, while reveal for negligible twist, already at this order, the appearance of wrapping. At two loops, as well as for next loops and orders, we can produce predictions, which may guide future string computations.Comment: Version 2 with: new exact expression for the Casimir energy derived (beyond the first two loops of the previous version); UV theory formulated and analysed extensively in the Appendix C; origin of the O(6) NLSM scattering clarified; typos correct and references adde

Culture of human cell lines by a pathogen-inactivated human platelet lysate

Alternatives to the use of fetal bovine serum (FBS) have been investigated to ensure xeno-free growth condition. In this study we evaluated the efficacy of human platelet lysate (PL) as a substitute of FBS for the in vitro culture of some human cell lines. PL was obtained by pools of pathogen inactivated human donor platelet (PLT) concentrates. Human leukemia cell lines (KG-1, K562, JURKAT, HL-60) and epithelial tumor cell lines (HeLa and MCF-7) were cultured with either FBS or PL. Changes in cell proliferation, viability, morphology, surface markers and cell cycle were evaluated for each cell line. Functional characteristics were analysed by drug sensitivity test and cytotoxicity assay. Our results demonstrated that PL can support growth and expansion of all cell lines, although the cells cultured in presence of PL experienced a less massive proliferation compared to those grown with FBS. We found a comparable percentage of viable specific marker-expressing cells in both conditions, confirming lineage fidelity in all cultures. Functionality assays showed that cells in both FBS- and PL-supported cultures maintained their normal responsiveness to adriamycin and NK cell-mediated lysis. Our findings indicate that PL is a feasible serum substitute for supporting growth and propagation of haematopoietic and epithelial cell lines with many advantages from a perspective of process standardization, ethicality and product safety

Scaling Functions in the Odd Charge Sector of Sine-Gordon/Massive Thirring Theory

A non-linear integral equation (NLIE) governing the finite size effects of excited states of even topological charge in the sine-Gordon (sG) / massive Thirring (mTh) field theory, deducible from a light-cone lattice formulation of the model, has been known for some time. In this letter we conjecture an extension of this NLIE to states with odd topological charge, thus completing the spectrum of the theory. The scaling functions obtained as solutions to our conjectured NLIE are compared successfully with Truncated Conformal Space data and the construction is shown to be compatible with all other facts known about the local Hilbert spaces of sG and mTh models. With the present results we have achieved a full control over the finite size behaviour of energy levels of sG/mTh theory.Comment: LaTeX2e, 12 pp., 3 eps figs. Remarks on locality adde

From the braided to the usual Yang-Baxter relation

Quantum monodromy matrices coming from a theory of two coupled (m)KdV equations are modified in order to satisfy the usual Yang-Baxter relation. As a consequence, a general connection between braided and {\it unbraided} (usual) Yang-Baxter algebras is derived and also analysed.Comment: 13 Latex page

The generalised scaling function: a systematic study

We describe a procedure for determining the generalised scaling functions $f_n(g)$ at all the values of the coupling constant. These functions describe the high spin contribution to the anomalous dimension of large twist operators (in the $sl(2)$ sector) of ${\cal N}=4$ SYM. At fixed $n$, $f_n(g)$ can be obtained by solving a linear integral equation (or, equivalently, a linear system with an infinite number of equations), whose inhomogeneous term only depends on the solutions at smaller $n$. In other words, the solution can be written in a recursive form and then explicitly worked out in the strong coupling regime. In this regime, we also emphasise the peculiar convergence of different quantities ('masses', related to the $f_n(g)$) to the unique mass gap of the $O(6)$ nonlinear sigma model and analyse the first next-to-leading order corrections.Comment: Latex version, journal version (with explanatory appendices and more references

The Effects of the Fear of Missing Out on People's Social Networking Sites Use During the COVID-19 Pandemic: The Mediating Role of Online Relational Closeness and Individuals' Online Communication Attitude

Forced isolation induced by COVID-19 pandemic dramatically impacted individuals' well-being, reducing the opportunities for social encounters, consequently resulting in a greater use of social media in order to maintain social relationships. Although the range of friend-related activities appeared to be severely constrained during quarantine, the Fear of Missing Out (FoMO) needs to be carefully examined, especially in relation to problematic social networking site use (PSNSU). Indeed, FoMO might enhance individuals' need to stay connected and communicate with other people, leading to PSNSU, in order to face the fear of being invisible in the world of social media in circumstances of physical isolation. The present study sought to evaluate the predictive role of FoMO on PSNSU during the COVID-19 pandemic, testing the mediating effect of online relational closeness and online communication attitude. A total of 487 Italian adults (59.3% women), aged between 18 and 70 years (mean age = 29.85 years; SD = 9.76), responded to an online survey during the period of COVID-19 pandemic lockdown in Italy. The survey included self-report measures assessing perceived FoMO, online communication attitude, relational closeness with online friends, and PSNSU. Participants declared they spent significantly more time social networking during the pandemic, particularly women. The total model accounted for a significant amount of variance in participants' PSNSU [R2 = 0.54; F(9, 447) = 58.285, p < 0.001). Despite the other people's social rewarding experiences had been drastically reduced by the lockdown, findings showed a direct effect of FoMO on PSNSU. Moreover, FoMO had an effect on online communication attitude and online relational closeness, although only online communication attitude predicted, in turn, PSNSU. Conversely, relational closeness on social networking sites did not predict PSNSU. The present study suggests that, during COVID-19 lockdown, FoMO levels may have strengthened attitudes toward online communication, which, in turn, may have put some individuals at risk of PSNSU