2,261 research outputs found
Partition Functions, Duality, and the Tube Metric
The partition function of type IIA and B strings on R^6xK3, in the T^4/Z_2
orbifold limit, is explicitly computed as a modular invariant sum over spin
strutures required by perturbative unitarity in order to extend the analysis to
include type II strings on R^6 x W4, where W4 is associated with the tube
metric conformal field theory, given by the degrees of freedom transverse to
the Neveu-Schwarz fivebrane solution. This generates partition functions and
perturbative spectra of string theories in six space-time dimensions,
associated with the modular invariants of the level k affine SU(2) Kac-Moody
algebra. These theories provide a conformal field theory (i.e. perturbative)
probe of non-perturbative (fivebrane) vacua. We contrast them with theories
whose N=(4,4) sigma-model action contains n_H=k+2 hypermultiplets as well as
vector supermultiplets, and where k is the level just mentioned. In Appendix B
we also give a D=6, N=(1,1) `free fermion' string model which has a different
moduli space of vacua from the 81 parameter space relevant to the above
examples.Comment: 24 pages, TE
Chiral persistent currents and magnetic susceptibilities in the parafermion quantum Hall states in the second Landau level with Aharonov-Bohm flux
Using the effective conformal field theory for the quantum Hall edge states
we propose a compact and convenient scheme for the computation of the periods,
amplitudes and temperature behavior of the chiral persistent currents and the
magnetic susceptibilities in the mesoscopic disk version of the Z_k parafermion
quantum Hall states in the second Landau level. Our numerical calculations show
that the persistent currents are periodic in the Aharonov-Bohm flux with period
exactly one flux quantum and have a diamagnetic nature. In the high-temperature
regime their amplitudes decay exponentially with increasing the temperature and
the corresponding exponents are universal characteristics of non-Fermi liquids.
Our theoretical results for these exponents are in perfect agreement with those
extracted from the numerical data and demonstrate that there is in general a
non-trivial contribution coming from the neutral sector. We emphasize the
crucial role of the non-holomorphic factors, first proposed by Cappelli and
Zemba in the context of the conformal field theory partition functions for the
quantum Hall states, which ensure the invariance of the annulus partition
function under the Laughlin spectral flow.Comment: 14 pages, RevTeX4, 7 figures (eps
Partition Functions of Non-Abelian Quantum Hall States
Partition functions of edge excitations are obtained for non-Abelian Hall
states in the second Landau level, such as the anti-Read-Rezayi state, the
Bonderson-Slingerland hierarchy and the Wen non-Abelian fluid, as well as for
the non-Abelian spin-singlet state. The derivation is straightforward and
unique starting from the non-Abelian conformal field theory data and solving
the modular invariance conditions. The partition functions provide a complete
account of the excitation spectrum and are used to describe experiments of
Coulomb blockade and thermopower.Comment: 42 pages, 3 figures; published version; minor corrections to sect.
4.
Composite Fermion Wavefunctions Derived by Conformal Field Theory
The Jain theory of hierarchical Hall states is reconsidered in the light of
recent analyses that have found exact relations between projected Jain
wavefunctions and conformal field theory correlators. We show that the
underlying conformal theory is precisely given by the W-infinity minimal models
introduced earlier. This theory involves a reduction of the multicomponent
Abelian theory that is similar to the projection to the lowest Landau level in
the Jain approach. The projection yields quasihole excitations obeying
non-Abelian fractional statistics. The analysis closely parallels the bosonic
conformal theory description of the Pfaffian and Read-Rezayi states.Comment: 4 pages, 1 figur
Neutral modes edge state dynamics through quantum point contacts
Dynamics of neutral modes for fractional quantum Hall states is investigated
for a quantum point contact geometry in the weak-backscattering regime. The
effective field theory introduced by Fradkin-Lopez for edge states in the Jain
sequence is generalized to the case of propagating neutral modes. The dominant
tunnelling processes are identified also in the presence of non-universal
phenomena induced by interactions. The crossover regime in the backscattering
current between tunnelling of single-quasiparticles and of agglomerates of
p-quasiparticles is analysed. We demonstrate that higher order cumulants of the
backscattering current fluctuations are a unique resource to study
quantitatively the competition between different carrier charges. We find that
propagating neutral modes are a necessary ingredient in order to explain this
crossover phenomena.Comment: 28 pages, 5 figure
The willingness to pay in the food sector. Testing the hypothesis of consumer preferences for some made in Italy products
Previous publications have shown that Italian consumers are willing to pay a premium price for certain categories of Made in Italy products. The premium price has proven to be higher in the food sector. This study provides an extensive literature review on the topic and aims to test a hypothesis regarding consumer preferences towards some Made in Italy food products of mass consumption (olive oil, meat and fish), with specific reference to the value systems that influence the purchase. This paper studies the correlation between the potential willingness to pay a premium price for the mentioned products and the characteristics of consumers' sample. The results obtained confirm the willingness to pay for Made in Italy products and correlate the willingness to pay a premium price with the level of education of the respondents to the questionnaire. Thus, these findings show that consumers with a higher educational level tend to make more sustainable food choices and by doing so lean toward a sustainable lifestyle
Thyroid hormonal profile in elderly patients treated with two different levothyroxine formulations: A single institute survey
A Case of Concurrent Riedel's, Hashimoto's and Acute Suppurative Thyroiditis
Riedel's thyroiditis (RT) is a rare form of infiltrative and inflammatory disease of the thyroid, first described by Bernard Riedel in 1896. The concurrent presence of RT and other thyroid diseases
has been reported, but, the association of RT with Hashimoto's thyroiditis and acute thyroiditis has
not yet been reported. We present a case of concurrent Riedel's, Hashimoto's and acute thyroiditis that occurred in a
45-year-old patient
Different expression of Defensin-B gene in the endometrium of mares of different age during the breeding season
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