1,586 research outputs found
A conformal field theory description of magnetic flux fractionalization in Josephson junction ladders
We show how the recently proposed effective theory for a Quantum Hall system
at "paired states" filling v=1 (Mod. Phys. Lett. A 15 (2000) 1679; Nucl. Phys.
B641 (2002) 547), the twisted model (TM), well adapts to describe the
phenomenology of Josephson Junction ladders (JJL) in the presence of defects.
In particular it is shown how naturally the phenomenon of flux
fractionalization takes place in such a description and its relation with the
discrete symmetries present in the TM. Furthermore we focus on closed
geometries, which enable us to analyze the topological properties of the ground
state of the system in relation to the presence of half flux quanta.Comment: 16 pages, 2 figure, Latex, revised versio
A conformal field theory description of the paired and parafermionic states in the quantum Hall effect
We extend the construction of the effective conformal field theory for the
Jain hierarchical fillings proposed in cond-mat/9912287 to the description of a
quantum Hall fluid at non standard fillings nu=m/(pm+2). The chiral primary
fields are found by using a procedure which induces twisted boundary conditions
on the m scalar fields; they appear as composite operators of a charged and
neutral component. The neutral modes describe parafermions and contribute to
the ground state wave function with a generalized Pfaffian term. Correlators of
Ne electrons in the presence of quasi-hole excitations are explicitly given for
m=2.Comment: 11 pages, plain Late
New Results on the Phase Diagram of the FFXY Model: A Twisted CFT Approach
The issue of the number, nature and sequence of phase transitions in the
fully frustrated XY (FFXY) model is a highly non trivial one due to the complex
interplay between its continuous and discrete degrees of freedom. In this
contribution we attack such a problem by means of a twisted conformal field
theory (CFT) approach and show how it gives rise to the U (1)
symmetry and to the whole spectrum of excitations of the FFXY model.Comment: 7 pages; talk given by G. Niccoli at "Path Integrals - New Trends and
Perspectives International Conference", Max-Planck-Institut, Dresden,
Germany, September 23 - 28, 200
Energy price increases and mitigation policies: Redistributive effects on Italian households
Since the second half of 2021, there has been a sharp increase in the prices of energy goods (electricity, heating gas, fuels) as well as of food, leading to inflation rates never experienced in Italy in the last forty years. Such high inflation rates prompted the Italian government to take measures to curb the prices of energy products, to increase social bonuses on electricity and gas bills, and to provide one-off allowances to households. The crucial question is what impact the price increases have had on households and whether the measures taken have protected the household sector from these increases. Therefore, we perform a microsimulation exercise on the period July 2021-March 2023 to quantify the effects of the price increases and of the measures on household expenditure and income. Our results indicate that the regressive impact of price increases was mitigated by the price containment measures
due to their progressive nature and that the contribution of one-off allowances and social bonuses was very relevant. In 2022, the year in which households benefitted from the measures for twelve months,
the fiscal policy interventions also succeeded in reducing inequality, the at-risk-of-poverty rate and energy poverty
A twisted conformal field theory description of the Quantum Hall Effect
We construct an effective conformal field theory by using a procedure which
induces twisted boundary conditions for the fundamental scalar fields. That
allows to describe a quantum Hall fluid at Jain hierarchical filling,
nu=m/(2pm+1), in terms of one charged scalar field and m-1 neutral ones. Then
the resulting algebra of the chiral primary fields is U(1)xW_m. Finally the
ground state wave functions are given as correlators of appropriate composite
fields (a-electrons).Comment: 11 pages, plain Late
Topological order in Josephson junction ladders with Mobius boundary conditions
We propose a CFT description for a closed one-dimensional fully frustrated
ladder of quantum Josephson junctions with Mobius boundary conditions, in
particular we show how such a system can develop topological order. Such a
property is crucial for its implementation as a "protected" solid state qubit.Comment: 14 pages, 3 figures, to appear in JSTA
Anomalies and Tadpoles in Open/Closed String Duality
We discuss the role played by the divergences appearing in the interaction
between a fractional D3 brane dressed with an SU(N) gauge field and a stack of
N fractional D3 branes on the orbifolds C^2/Z_2 and C^3/(Z_2 x Z_2). In
particular we show that the logarithmic divergences in the closed string
channel, interpreted as due to twisted massless tadpoles, are mapped, under
open/closed string duality, in the logarithmic ones in the open string channel,
due to the massless states circulating in the annulus diagram and corresponding
to the one-loop divergences that one finds in the gauge theory living in the
world volume of the brane. This result provides a quantitative evidence of why
the chiral and scale anomalies of the supersymmetric and non conformal gauge
theories supported by the world volume of the branes can be inferred from
supergravity calculations.Comment: LaTeX, 8 pages. Contribution to the proceedings of the workshop of
the RTN Network "The quantum structure of space-time and the geometric nature
of fundamental interactions", Copenhagen, September 200
Polyamine–Drug Conjugates: Do They Boost Drug Activity?
Over the past two decades, the strategy of conjugating polyamine tails with bioactive molecules such as anticancer and antimicrobial agents, as well as antioxidant and neuroprotective scaffolds, has been widely exploited to enhance their pharmacological profile. Polyamine transport is elevated in many pathological conditions, suggesting that the polyamine portion could improve cellular and subcellular uptake of the conjugate via the polyamine transporter system. In this review, we have presented a glimpse on the polyamine conjugate scenario, classified by therapeutic area, of the last decade with the aim of highlighting achievements and fostering future developments
Hyaluronic Acid Inhibits Polycation Induced Cellular Responses
Positively charged macromolecules cause a variety of pathological
events through their electrostatic interaction with anionic sites
present on the membrane of target cells. In the present study we have
investigated the effect of hyaluronic acid, a negatively charged
molecule, on rat paw oedema induced by poly-L-lysine as well as on
histamine release from rat mast cells and nitric oxide formation
from rabbit aorta, both induced by this polycation. The results
indicate that hyaluronic acid is able to suppress these
poly-L-lysine induced effects with a mechanism which possibly
depends on its negative charges which may balance the effects of
positively charged polycations
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