A
bstract
We study a new hermitian one-matrix model containing a logarithmic Penner’s type term and another term, which can be obtained as a limit from logarithmic terms. For small coupling, the ...potential has an absolute minimum at the origin, but beyond a certain value of the coupling the potential develops a double well. For a higher critical value of the coupling, the system undergoes a large
N
third-order phase transition.
A
bstract
We consider defect operators in scalar field theories in dimensions
d
= 4 −
ϵ
and
d
= 6 −
ϵ
with self-interactions given by a general marginal potential. In a double scaling limit, where ...the bulk couplings go to zero and the defect couplings go to infinity, the bulk theory becomes classical and the quantum defect theory can be solved order by order in perturbation theory. We compute the defect
β
functions to two loops and study the Renormalization Group flows. The defect fixed points can move and merge, leading to fixed point annihilation; and they exhibit a remarkable factorization property where the
c
-dependence gets disentangled from the coupling dependence.
A
bstract
For the general theory of nonlinear electrodynamics (NLED) we prove that causality implies both the Dominant Energy Condition (DEC) and, surprisingly, the Strong Energy Condition (SEC). ...This has implications for gravitational applications, such as regular black holes supported by NLED matter. For self-dual NLED theories, weak-field causality alone implies both the DEC and SEC, as we illustrate with Born-Infeld and ModMax electrodynamics.
A
bstract
We study 2-point and 3-point functions in CFT at finite temperature for large dimension operators using holography. The 2-point function leads to a universal formula for the holographic ...free energy in
d
dimensions in terms of the
c
-anomaly coefficient. By including
α
′ corrections to the black brane background, we reproduce the leading correction at strong coupling. In turn, 3-point functions have a very intricate structure, exhibiting a number of interesting properties. In simple cases, we find an analytic formula. When the dimensions satisfy ∆
i
= ∆
j
+ ∆
k
, the thermal 3-point function satisfies a factorization property. We argue that in
d >
2 factorization is a reflection of the semiclassical regime.
A
bstract
We compute correlation functions of chiral primary operators in
N
=
2
super-conformal theories at large
N
using a construction based on supersymmetric localization recently developed by ...Gerchkovitz et al. We focus on
N
=
4
SYM as well as on supercon-formal QCD. In the case of
N
=
4
we recover the free field theory results as expected due to non-renormalization theorems. In the case of superconformal QCD we study the planar expansion in the large
N
limit. The final correlators admit a simple generalization to a finite
N
formula which exactly matches the various small
N
results in the literature.
We propose a novel data-driven framework for assessing the a-priori epidemic risk of a geographical area and for identifying high-risk areas within a country. Our risk index is evaluated as a ...function of three different components: the hazard of the disease, the exposure of the area and the vulnerability of its inhabitants. As an application, we discuss the case of COVID-19 outbreak in Italy. We characterize each of the twenty Italian regions by using available historical data on air pollution, human mobility, winter temperature, housing concentration, health care density, population size and age. We find that the epidemic risk is higher in some of the Northern regions with respect to Central and Southern Italy. The corresponding risk index shows correlations with the available official data on the number of infected individuals, patients in intensive care and deceased patients, and can help explaining why regions such as Lombardia, Emilia-Romagna, Piemonte and Veneto have suffered much more than the rest of the country. Although the COVID-19 outbreak started in both North (Lombardia) and Central Italy (Lazio) almost at the same time, when the first cases were officially certified at the beginning of 2020, the disease has spread faster and with heavier consequences in regions with higher epidemic risk. Our framework can be extended and tested on other epidemic data, such as those on seasonal flu, and applied to other countries. We also present a policy model connected with our methodology, which might help policy-makers to take informed decisions.
The use of concentrated brines and brackish water as feed solutions in reverse electrodialysis represents a valuable alternative to the use of river/sea water, allowing the enhancement of power ...output through the increase of driving force and reduction of internal stack resistance. Apart from a number of theoretical works, very few experimental investigations have been performed so far to explore this possibility.
In the present work, two RED units of different size were tested using artificial saline solutions. The effects of feed concentration, temperature and flowrate on process performance parameters were analysed, adopting two different sets of membranes. These experiments allowed to identify the most favourable conditions for maximising the power output within the presently investigated range, i.e. 0.1M NaCl as diluate and 5M NaCl as concentrate at 40°C. Under these conditions a power density equal to 12W/m2cell_pair was reached, among the highest so far reported in the literature. Increasing the unit size a slight reduction in power density was observed. These results indicate new directions for a successful scale-up and development of the Reverse Electrodialysis technology.
Display omitted
•A wide experimental campaign performed on RED process using brine and saline waters.•Gross and Net Power and Energy Efficiency were measured with two different sets of IEMs.•Optimal conditions were identified using brine and brackish water at 40°C.•Max power density of 8 and 12W/m2cell pair reached with the two sets of IEMs.•Two different sizes investigated for the RED unit, to analyse scale-up effects.
Protontherapy is hadrontherapy's fastest-growing modality and a pillar in the battle against cancer. Hadrontherapy's superiority lies in its inverted depth-dose profile, hence tumour-confined ...irradiation. Protons, however, lack distinct radiobiological advantages over photons or electrons. Higher LET (Linear Energy Transfer)
C-ions can overcome cancer radioresistance: DNA lesion complexity increases with LET, resulting in efficient cell killing, i.e. higher Relative Biological Effectiveness (RBE). However, economic and radiobiological issues hamper
C-ion clinical amenability. Thus, enhancing proton RBE is desirable. To this end, we exploited the p +
B → 3α reaction to generate high-LET alpha particles with a clinical proton beam. To maximize the reaction rate, we used sodium borocaptate (BSH) with natural boron content. Boron-Neutron Capture Therapy (BNCT) uses
B-enriched BSH for neutron irradiation-triggered alpha particles. We recorded significantly increased cellular lethality and chromosome aberration complexity. A strategy combining protontherapy's ballistic precision with the higher RBE promised by BNCT and
C-ion therapy is thus demonstrated.
A
bstract
We compute general higher-point functions in the sector of large charge operators
ϕ
n
,
ϕ
¯
n
at large charge in O(2)
ϕ
¯
ϕ
2
theory. We find that there is a special class of “extremal” ...correlators having only one insertion of
ϕ
¯
n
that have a remarkably simple form in the double-scaling limit
n
→∞ at fixed
g n
2
≡ λ, where
g
~
ϵ
is the coupling at the O(2) Wilson-Fisher fixed point in 4 −
ϵ
dimensions. In this limit, also non-extremal correlators can be computed. As an example, we give the complete formula for
ϕ
x
1
n
ϕ
x
2
n
ϕ
¯
x
3
n
ϕ
¯
x
4
n
, which reveals an interesting structure.
A
bstract
The generic scale-invariant theory of an axion and a dilaton coupled to gravity in
d
-dimensions is generalized to a ‘universal’ one-axion model with two dilatons that reproduces itself ...under consistent dimensional-reduction/truncation. Flat FLRW cosmologies are shown to correspond to trajectories of a three-dimensional autonomous dynamical system, which we analyse with a focus on accelerated cosmic expansion, deriving the precise swampland bounds that exclude eternal acceleration. We also show that for two sets of values of its three independent parameters, the model is a consistent truncation of maximal ‘massive’ supergravity theories arising from string/M-theory; for these maximal-supergravity parameter values the FLRW cosmologies include some with a transient de Sitter-like phase, but not the recurring de Sitter-like phase or eternal cosmic acceleration that is possible for other parameter values.
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